The International Journal of Oral & Maxillofacial Implants, Pre-Print

Purpose: The goal of successful implant placement is to maintain a long-term stable marginal peri-implant bone level (MBL). This retrospective study investigated the MBL of reduceddiameter implants (RDI). The implants were analyzed in different indication in the context of various surgical and prosthetic treatment strategies using heterogeneous data from a private practice. Mixed model analysis was used to process the heterogeneous data structure. This method has not been a standard method of data analysis in implantology, and it shows considerable advantages over conventional variance analyses regarding data integration from outpatient practices. Method: 123 patients were treated with 326 implants. 247 implants were diameter-reduced, the remaining 79 implants were standard implants (SDI) as patient related controls. The mean observation time was 24.4 months, and the maximum observation time 76.0 months. The peri-implant bone level of the implants was evaluated, while considering the diameter, as well as the time of implant placement, time of loading, extent of augmentation and localization of the implants. The data were evaluated after restructuring using mixed model analysis. Result: No significant difference was found between the use of RDI or SDI in the analyzed indication. Furthermore, no significant difference was found for the implant placement time, loading time, and the use of two-stage augmentations regarding the stability of the peri-implant bone level. Conclusion: Narrow-diameter implants are a sufficient treatment option in horizontally deficient bone conditions. The use of diameterreduced implants in the posterior region shows promising results; 3.5mm diameter implants may be indicated considering the individual patient situation. The use of mixed model analysis for the evaluation of heterogeneous practice data can lead to a significant increase in the number of retrospective studies and data integration from practices, forming a sound basis for evidence-based dentistry. Schlagwörter: dental implants, implant diameter, mixed model analysis, bone augmentation marginal bone level

Introduction: Knowing that osteoporosis is a metabolic disease that could decrease dental implant success and survival, the purpose of this review was to gather information on the characteristics of implant osseointegration in animal models of induced osteoporosis. By pointing out the role of some factors that could improve the success rate in these situations, this study aimed to enhance the knowledge about this process that can be further translated to clinical designs. Methods: A systematic search in PubMed/Medline, Lilacs, Cochrane Library, Scopus and Web of Science was conducted to identify information between 2002 and 2023 regarding osseointegration of dental implants in animal models of induced osteoporosis. The following search strategy was utilized and adjusted to each database: (((dental implant) AND (Osseointegration)) AND (osteoporosis)) AND/OR (osteoporosis treatment). The inclusion criteria were animal studies in English, involving the placement of an osseointegrated implant in osteoporotic bone, and evaluating bone to implant contact (BIC) %. Exclusion criteria were studies in humans, in vitro studies, procedures involving any kind of bone graft and studies evaluating medication related osteonecrosis of the jaw. A standardized data extraction form was used to record data for each study, covering article title, date, authors, number of animals, purpose of study, type of analysis used by authors, follow-up, type of implant, test and control groups, intervention and conclusions. The risk of bias of the included studies was assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) Risk of Bias tool.20 Results: A total of 204 articles were found for evaluation and selection. All of the 43 selected studies evaluated the bone-implant contact (BIC) %. Other parameters such as bone to implant mechanical interface, bone area (BA) and bone volume (BV) ratio were also evaluated in some of the studies. There was a tendency for compromised results of implant osseointegration in the presence of osteoporosis. Modification of the implant surface, systemic and local use of anti-resorptive drugs and other substances, showed benefits for the implant success in osteoporotic sites. Still, no consensus among studies on the superiority of systemic medications in improving the process of peri-implant bone repair, was observed. Conclusion: Although it is possible to improve the osseointegration of implants in osteoporotic bone, either by using systemic or local factors, the metabolic bone syndrome caused by osteoporosis can jeopardize the osseointegration of dental implants. Schlagwörter: dental implants, osseointegration, osteoporosis, osteoporosis treatment, bone, implant surface modifications

Purpose: To evaluate the fracture load of monolithic zirconia crowns with implant screw holes, focusing on variations in occlusal and axial thicknesses, and to assess the interaction between these variables. Materials and Methods: Six different prostheses were designed using CAD software, varying in occlusal thickness (0.5 mm, 1.0 mm) and axial thickness (0.4 mm, 0.8 mm, 1.2 mm) based on the height and thickness differences of the titanium implant abutment. Twelve specimens per design were created by milling zirconia blocks and titanium abutments. These specimens were cemented with resin and subjected to thermomechanical aging (50 N, 200,000 cycles, 5°C-55°C, 30 seconds dwell time) using a chewing simulator. Static loading was applied using a universal testing machine at a rate of 0.5 mm/min until fracture occurred, and the load value (N) at the moment of the initial fracture was recorded. Fracture pattern and surface analyses were performed. Statistical analyses included two-way analysis of variance, Tukey HSD test, multiple regression analysis, and Fisher’s exact test. Results: Both occlusal and axial thicknesses significantly influenced the fracture load (P < .05), with a significant interaction between them (P < .05). An occlusal thickness of 1.0 mm exhibited a significantly higher fracture load compared to 0.5 mm (P < .05). An axial thickness of 1.2 mm showed a significantly higher fracture load compared to 0.4 mm and 0.8 mm (P < .05). The difference in axial thickness between 0.8 mm and 1.2 mm had a more substantial impact on fracture load than the difference in occlusal thickness between 0.5 mm and 1.0 mm (P < .05). Fractographic analysis showed that the thin axial wall exhibited twist hackles without involvement of the crown margin, whereas the thick axial wall exhibited no hackles and a more catastrophic failure involving the crown margin. Conclusion: For monolithic zirconia crowns with implant screw holes, when sufficient occlusal thickness cannot be achieved, an axial thickness of at least 1.2 mm is recommended to ensure higher fracture resistance. Schlagwörter: zirconia crown, implant-supported fixed dental prosthesis, screw hole, occlusal thickness, axial thickness, fracture load

Purpose: developing customized titanium specimens, with innovative surfaces, is a suitable strategy to overcome implant failure. Additionally, a faster and efficient osteogenic commitment assists tissue regeneration. To investigate the interplay between inflammation and differentiation upon implantation, Dental Pulp Stem Cells (DPSCs) were cultured on 3D-printed titanium owning an internal open cell form, administering osteogenic factors by a liposomal formulation (LipoMix) compared to traditional delivery of differentiation medium (DM). Materials and Methods: osteogenic differentiation was evaluated by western blot, by measuring β1 integrin expression, and by and real-time RT-PCR, by measuring SP7 and Collagen I gene expression; while.angiogenesis was characterized by measuring VEGF secretion levels. Matrix mineralization was assessed by means of Alizarin Red Staining, cell adhesion and inflammation responses through western blot, enzymatic and ELISA assays evaluating Nrf2 expression, catalase activity and Prostaglandin E2 secretion, respectively. Results: LipoMix enhances cell proliferation and adhesion, as revealed by increased integrin β1 expression. Mineralized matrix deposition, SP7 gene expression, Collagen I release and Alkaline Phosphatase activity appear increased in LipoMix condition. Additionally, the redox-sensitive transcription factor Nrf2 is overexpressed at the earliest experimental times, triggering the catalase activity. Conclusions: data reported confirm that internal topography and post-production treatments on titanium surfaces dynamically and positively condition the DPSC progress towards the osteogenic phenotype, moreover, the combination with LipoMix fastens the positive modulation of inflammation under osteogenic conditions. Therefore, the development of customized surfaces along with the administration of differentiating factors enclosed in a liposomal delivery system, could represent a promising and innovative tool in regenerative dentistry. Schlagwörter: osteogenic differentiation, NF-E2-Related Factor 2, liposomal formulation, stem cells, regenerative dentistry

Purpose: To compare the prosthetic outcomes of screw-retained monolithic zirconia (Zr) single crowns supported by either narrow-diameter (3.3 mm) or standard-diameter (4.1 mm) tissue-level titanium-zirconia (TiZr) implants in posterior sites. Materials and Methods: A total of 18 participants, each with a missing molar or premolar tooth requiring an implantsupported single crown, were randomly assigned to either the test or control group. All participants received screwretained monolithic Zr single crowns supported by single tissue-level TiZr implants. Test group participants received narrow-diameter implants (3.3 mm), whereas control group participants received standard-diameter implants (4.1 mm). A modified version of the United States Public Health Service (USPHS) criteria was used to assess the prosthetic outcome across 12 parameters after 1 year of function. Data were analyzed descriptively, and statistical analysis was performed using a statistical software (SPSS, Version 28.0; IBM) with the level of significance set at P < .05. Results: Of the 18 single crowns delivered, 16 were available for review at the 1-year follow-up, including 7 in the test group and 9 in the control group. Patient characteristics and crown site distribution were similar, with no significant differences observed between the two groups (chi-square test; P < .05). There were no crown failures, meaning a crown survival rate of 100% was achieved after 1 year. The prosthetic outcome based on USPHS criteria was comparable between the two groups with no significant differences observed (chi-square test; P < .05). There were 19 prosthetic events in total (10 in the test group and 9 in the control group), with no significant differences between the groups (chi-square test; P < .05). Loss of proximal contact was the dominant event, with a total of eight events (three in the test group and five in the control group). Patient satisfaction after 1 year was high in both treatment groups, with no significant differences detected. Conclusions: Screw-retained monolithic Zr single crowns supported by either narrow- or standard-diameter tissue-level TiZr implants in posterior sites have comparable prosthetic outcomes after 1 year. Long-term results from well-designed trials are still needed to validate the findings of the present study.

Purpose: Implant-supported overdentures have been an effective treatment method for edentulous mandibles. However, the loading time after implant placement is still controversial. The purpose of this study was to evaluate the outcome of implant-supported overdentures using telescopic crowns for the treatment of edentulous patients with immediate loading protocol. Materials and Methods: This study was conducted on 22 edentulous mandibular patients visiting the Department of High Technique, National Hospital of Odonto – Stomatology, Ho Chi Minh City, Vietnam for prosthodontic rehabilitation. Each patient received four interforaminal implants. Immediate loading protocol was applied, and Ankylos Syncone copings systems was used to connect the prosthesis and the implants. The survival rate of implants and prostheses, as the primary outcome, were evaluated at 6 months, 01 year, and 02 years post-surgery. Peri-implant tissue condition, peri-implant bone loss, and patient satisfaction were the secondary outcomes. Results: The implant survival rate was 98.9% with 01 failed implant. The peri-implant bone loss changes after 6 months, 01 year, and 02 years were 0.07 ± 0.22 mm, 0.12 ± 0.3 mm, and 0.15 ± 0.2 mm, respectively. No gingival hyperplasia was recorded. The prosthesis survival rate was 86.4% with 1 fractured overdenture, 1 overdenture relining and 1 abutment fracture. Conclusions: Mandibular rehabilitation using implant-supported overdenture with telescopic crowns and immediate loading protocol showed high survival rates of both implant and prosthesis in 2-year follow-up. Schlagwörter: immediate loading, implant-supported overdenture, edentulous mandible, telescopic denture, implant survival rate

Purpose. To evaluate how implant analog design and printing layer thickness affect the linear and angular accuracy of implant analogs in additively manufactured casts, comparing with conventional implant analogs in stone casts. Material and Methods. A reference cobalt chromium mandibular model with a single implant was digitized with an industrial optical scanner and scan bodies compatible with a pressure/friction fit (S) or a screw-retained (N)  implant analog for direct digital workflow. These scans were used to fabricate casts with 50 μm (S-50 and N-50) and 100 μm (S-100 and N-100) layer thickness (n=10). Ten stone casts were made after single-step closed-tray polyvinylsiloxane impressions of the model (CNV). All casts were digitized with the same metal scan body and scanner used to digitize the master model, and these scans were superimposed over the scan of the master model to measure the linear (x, y, and z-axes) and angular (XY and YZ planes) deviations (Geomagic Control X). The precision of measured deviations was defined with the average deviation values. Generalized linear model analysis was used to compare the deviations within implant analogs for direct digital workflow, while 1-way analysis of variance and Dunnett’s test were used to compare these analogs and conventional analogs (α = .05) Results. The analog design affected the linear deviations (y-axis), while the interaction between the analog design and the layer thickness, and the analog design affected the angular deviations (XY plane, P ≤ .030). S analogs had lower linear and angular deviations than N analogs, and S-50 led to lower angular deviations than N-50 (P ≤ .030). CNV led to higher linear accuracy (y-axis) than N-50, N-100, and S-100 and led to lower angular deviations than all test groups (XY plane) (P ≤ .025). Conclusions. The analogs in S-50 casts had positional trueness similar to or higher than those in other test groups and their accuracy was mostly similar to those in CNV casts. Implant analogs for direct digital workflow deviated more towards lingual and gingival, and conventional analogs deviated more towards buccal, occlusal, and distal. All analogs had a tendency to tilt towards lingual and distal. Schlagwörter: Analog design; angular deviation; implant analog; layer thickness; linear deviation

Purpose: Evaluation of seating accuracy of interim crowns for the immediate restoration of immediate implants (I-Imp) and delayed implants (D-Imp) placed via static computer-assisted implant surgery (sCAIS). Materials and Methods: A maxillary training model was modified by removing the central incisors and simulating fresh extraction socket in one site and healed ridge on the other site. An I-Imp was planned in the extraction socket and D-Imp was planned in the healed site. The planned implants were used to design sCAIS surgical template and interim crowns for immediate restoration of the implants. Fourteen surgical models received sCAIS implants after which the interim crowns were inserted. Subsequently, the models with the seated crowns were scanned by a laboratory scanner. The planning virtual model was superimposed against every surgical model to measure vertical, horizontal and proximal contact errors of each crown. Results: All the crowns were positioned more incisally than the planned crowns. This was significantly more noticeable for the D-Imp crowns (0.81 mm) than the I-Imp crowns (0.55 mm). The 2 crown groups had similar horizontal errors (I-Imp =0.35 mm, D-Imp = 0.36 mm). The D-Imp crowns had minimal proximal contact error (0.14 mm), but the I-Imp crowns had significantly greater proximal contact error (0.74 mm) in the form of open distal contacts. This pattern of error appears related to the relationship between the socket morphology and the planned implant position. Conclusions: Prefabricated interim I-Imp crowns suffered from greater errors that affected the proximal contact quality than DImp crowns. The observed deviation of the I-Imp crowns can be attributed to the socket morphology and its relation to the planned implant position. The deviations of the I-Imp crowns are clinically significant and will require clinical adjustments. Thus, caution is needed before routine use of prefabricated interim crowns on I-Imp.

Purpose: To assess the efficacy and safety of a sticky dual-phase porcine-derived bone substitute, compared to a similar non-adhesive graft, in addressing induced perforations of the Schneider membrane during sinus lift using a within-subject design rabbit model. Materials and Methods: Bilateral sinus floor elevations were performed in 12 rabbits. The sinus mucosa was intentionally perforated using a blade on both sides and randomly filled with either a cortico-cancellous bone embedded in a 20% thermosensitive gel (GTO sticky bone test) or a cortical cancellous bone and 10% collagen (mp3 control). Healing progress was evaluated after 2 and 10 weeks in 6 animals at each time-point, with cone-beam computed tomography (CBCT), micro-computed tomography (microCT) and histological assessments. Results: One animal of the 2-week group died but was substituted. No other complications were observed. At 2-week, on CBCTs, biomaterials particles were observed in the vicinity of the Schneider membrane in two out of six sinuses of each group, but never dispersed into the sinus. MicroCT and histology consistently revealed few granules beyond the elevated region. Histologically, five sinuses in the mp3 group and two sinuses in the GTO group exhibited granules outside the elevated region but in the vicinity of the perforations. In the 10-week groups, the number of affected sinuses decreased to one in the mp3 group and two in the GTO group. Throughout all observations, the graft granules consistently resided proximate to the elevated region. Micro-CT demonstrated a reduction in the volume of the elevated region by approximately 12% after 2 weeks and 50-54% after 10 weeks. Conclusions: The use of both sticky and non-sticky bone substitutes seems to prevent a substantial amount of particles from extruding through an induced perforation of the Schneiderian membrane. This suggests that it could be possible to use a sticky bone as an alternative to a barrier membrane to avoid the extrusion of bone granules in the presence of accidental perforation of the sinus membrane in clinical practice. After 10 weeks of healing, the volume of the elevated region decreased by approximately 50%, possibly due to biomaterial resorption and loss through the surgically created perforation. Schlagwörter: Sinus lift; Bone substitute; Histomorphometric; Sticky bone; Schneider membrane perforation

Osseointegration of implants is significant in determining implant success. Factors influencing osseointegration include the good hydrophilicity (wettability) of the implant surface. Purpose: The purpose of this study was to investigate the free surface energy before and after CO2 irradiation on rough titanium surfaces. Material and Methods: Sandblasted, large grit, acidetched (SLA) implant surfaces were used for this study. Contact angle evaluations were performed for saline, albumin, and artificial blood using a contact angle goniometer in 25°C and 37°C (20 droplets in each group, 120 in total). The titanium disks were then irradiated with a CO2 laser (10,600 nm) using a non-contact, defocused, 2W continuous wave for 30 seconds. Contact angle measurements for saline, albumin and artificial blood were evaluated immediately after irradiation (new 120 in total contact angle measurements) and compared with the measurements before laser irradiation. Paired t-test using SPSS was performed for 5% statistical significance level. Results: Lower numbers of contact angle measurements were found and changes after CO2-laser irradiation were statistically significant (p < 0.05) for all groups except for albumin at 25°C, as follows: 25℃: (saline) (Pre) 111.97° ±13.67°, (Post) 79.29° ±10.83° / p<0.0001; (albumin) (Pre) 89.04° ±12.02°, (Post) 83.29° ±20.71° / p=0.297; (blood) (Pre) 97.79° ±14.44°, (Post) 86.29° ±10.82° / p=0.019; 37℃: (saline) (Pre) 104.12° ±13.138°, (Post) 92.66° ±4.777° / p=0.001; (albumin) (Pre) 89.04° ±12.02°, (Post) 83.29° ±20.71° / p=0.297 (blood) (Pre) 80.42° ±19.00°, (Post) 58.62° ±24.34° / p=0.012. Conclusion: The CO2 laser irradiation in general positively affected the wettability and hydrophilicity of rough titanium (SLA) surfaces. Schlagwörter: CO2 lasers; contact angle; irradiation; wettability

The development of a successful bone grafting technology with cohesive and adhesive properties has been an elusive goal for dental and orthopedic researchers. Tetracalcium phosphate combined with phosphoserine (TTCP-PS) is a synthetic, injectable, cohesive, self-setting, mineral-organic wet-field adhesive. The objective of this study was to evaluate four formulations of TTCP-PS in comparison to the conventional grafting materials, Bioglass and deproteinized cancellous bovine bone with a bioresorbable collagen membrane in standardized defects created in the angle of the rat mandible. Microcomputed tomography and histomorphometry were utilized to evaluate bone replacement with each of these materials after in vivo residence of either 4 or 12 weeks. The results of this study demonstrate that specific TTCP-PS formulations can form bone comparable to conventional materials in an osteopromotive mechanism but with the advantage of having cohesive and adhesive properties.

Purpose: The study investigated the cumulative survival rate (CSR) and marginal bone loss (MBL) of single implants immediately placed and restored with two-unit cantilevered fixed dental prostheses after extraction of two adjacent mandibular incisors with a compromised periodontal condition. Materials and methods: Patients in need of extraction and replacement of two adjacent mandibular incisors due to advanced periodontal loss of attachment were treated consecutively. Following a flapless procedure, a single implant was inserted at the time of extraction in one of the two fresh alveoli sockets and immediately restored with a screw retained two-unit provisional FDP. The area of extraction was grafted using xenograft particulate material. Peri-implant soft tissue and hard tissue condition at the last follow-up appointment, marginal bone loss at the last follow-up appointment at least 1 year after the delivery of the final prosthesis, and the final aesthetic result were evaluated. Results: Twenty patients were recruited between January 2014 and December 2019 in a single private practice and each received single implants and immediate provisional restoration with a two-unit cantilevered fixed dental prosthesis. Patients were followed for 22 to 94 months (average follow-up = 4 years) and none of the implants failed resulting in 100% CSR. Cumulative MBL -measured using the VixWin Platinum software -was 1.08 +/- 0.35. A lower MBL was observed in the presence of platform switching (0.63 +/- 0.11 mm) compared to the absence of platform switching (1.27 +/- 0.20 mm). Conclusions: The preliminary results obtained from this study suggest that patients in need of replacing two adjacent periodontally compromised mandibular incisors can be treated with an immediately inserted and restored single implant. Schlagwörter: mandibular incisor, narrow implants, immediate restoration, partial edentulism, immediate placement

Purpose: The aim of this study was to examine and compare the mechanical success of customized computer aided design and manufacturing (CAD-CAM) and prefabricated abutments and screws before and after cyclic loading, through measuring removal torque values. Materials And Methods: The study was performed in accordance with ISO 14801:2016 standarts. Twenty eight dental implants with identical charecteristics were divided into two equal groups. The control group comprised of prefabricated abutments and screws, while the study group included customized CAD-CAM abutments and screws. Removal torque values (RTV) were measured before and after 50.000 and 1 million cyclic loading in both groups. Additionally, to evaluate the screw fatigue performance, they were retightened with 30N torque and RTV measurements were repeated. The data were analyzed using ANOVA, Newman Keuls test and paired t-test. Results: No significant difference was observed in RTVs before cylic loading within each group. However, the RTV's measured before cyclic loading were found to be significantly lower in the study group compared to the control group. Both groups exhibited a significant decrease in RTV after cylic loading. The RTV of the study group was significantly lower than the control group especially after 1 million cycles. No significant difference was found in the screw fatigue performance between two groups. Conclusion: The significantly lower RTVs of customized CAD-CAM abutments and screws before and after cylic loading have raised questions about their effectiveness and widespread use. This study underscores the necessity for further clinical investigations comparing the mechanical success of custom and prefabricated abutments and screws.

Purpose: This systematic review and meta-analysis aimed to investigate the clinical outcomes of xenogeneic bone blocks (XBB) used for lateral ridge augmentation, specifically focusing on bone gain, graft survival, and implant survival. Materials and Methods: Data search was conducted in Pubmed, Embase, and ClinicalTrial.gov for randomized controlled trials (RCTs), and prospective cohort studies up to March 1, 2024. Horizontal bone gain (HBG), horizontal bone resorption (HBR), graft survival rate, and implant survival rate were analyzed. Cochrane Risk of Bias Tool 2 and Newcastle-Ottawa Scale were applied to assess the quality and risks of the included studies. Results: Four RCTs and five prospective cohortstudies, comprised 120 graft sites and 141 implants in total were included for the meta- analysis. Non-comparative analysis resulted in a weighted mean horizontal bone gain (HBG) of 4.38 mm and horizontal bone resorption (HBR) of 0.85 mm. Comparative analysis with data from 4 RCTs that paired xenogeneic bone block (XBB) with autogenous bone block (ABB) exhibited a statistically significant greater HBG in XBB, with a mean difference of 0.72mm (95% CI=0.067 to 1.382, p=0.031, I2=28.2%). The weighted graft survival rate for XBB was 91.3% (95% CI = 76.6% to 97.1%, I2 = 58.0 %), and the weighted implant survival rate was 84.3% (95% CI = 72.6% to 91.6%, I2 = 31.6 %). Histologically, mean percentage of mineralized vital bone in XBB ranged from 11.6% to 29.8%, and the resorption rate ranged from 7.3% to 21%. Conclusion: The utilization of xenogeneic bone block for lateral ridge augmentation demonstrates an acceptable survival rate and yields an adequate volume of bone for subsequent implant therapy. Nonetheless, the survival rate of implants placed in ridges augmented with xenogeneic blocks is less favorable when compared to those augmented with autogenous block grafts.

Purpose: The objective of this study was to examine the variables that influence the stability of secondary orthodontic anchoring miniscrews after the occurrence of initial installation failure. The secondary insertion was defined as reinserted, which was inserted to the orthotopic (i.e., inserted between the roots of the original two adjacent teeth with the mesiodistal, height and insertion angle slightly altered) and ectopic (i.e., inserted between neighboring tooth roots). Materials and methods: A total of 100 miniscrews were reinserted in 71 patients who experienced primary insertion failure. The analysis considered 15 independent variables related to systemic factors and site characteristics. The success rate and risk factors associated with reinsertion were assessed using univariate analysis (Chi-square Test for categorical variables and Mann-Whitney U test for continuous variables) and correlation analysis (Spearman correlation analysis to exclude variables that might cause interference in a multivariable model). Significant parameters from univariate analysis were then integrated into a generalized estimating equation (GEE) model. Results: The success rate of reinsertion was 66.00% (66/100), and the cancellous bone density and the patient’s age had a strong correlation with the stability of reinserted miniscrews. Conclusion: The study indicates that younger patients with miniscrews reinserted in areas of high cancellous bone density are more likely to experience instability. This finding warrants careful consideration by orthodontists when performing miniscrew reinsertion procedures. Schlagwörter: miniscrew, reinsertion, stability, risk factors

Objective: The goal of this observational study was to evaluate the occurrence, incidence rate, and esthetic impact of facial growth in adult patients subjected to rehabilitation with single implants on the anterior maxillary region (pre-maxilla), specifically in the central incisors, to evaluate the influence of time on changes in the incisal level. Methods: Patients who received single implants in #11 or #21 (A.D.A. #8 or #9), with age greater than nineteen years old on the date they received the implant and with the presence of adjacent teeth, were included. As exclusion criteria: implants with less than five years of installation, implants adjacent to dental elements that have undergone some anatomical change in the incisal area due to restorations, fractures, or excessive wear; rehabilitation with implants in both central upper incisors. Standardized pictures were obtained to evaluate the presence and incidence of incisal linear changes. All rehabilitation followed the same standard of reconstruction and received the same incisal level of the homologous and adjacent tooth in order to mimicry and achieve the best esthetic for the patient. Thus, in T0, the incisal level difference between the crown and the adjacent tooth was zero; any modification in the incisal levels, from 1.0 mm of difference, was registered. It was considered 1.0 mm as the cutoff mark because this number permits easy observation of any difference, either by professional or patient. The data obtained were analyzed and correlated statistically. Results: A total of 56 patients/implants were included (aged between 23 and 63; an average of 40.79 ± 12.25); incisal level alteration between teeth and implants was found, leading to an incidence rate of 19.6% of patients. The study had an average follow-up of 10.7 ± 3.37 years. All implants evaluated had stability and healthy peri-implant tissue condition throughout the follow-up, with a 100% survival rate. There was no statistically significant prevalence of incisal level changes between males (19%) and females (20%) (p=0.238); there was an incidence of 41.7% in the group between 20 and 30 years old, 13.3% between 30 and 40 years old, 23.7% between 40 and 50 years old, and 6.3% in the group over 50 years old was found, but with no statistically significant differences (p=0.118) among different age groups. Similarly, no statistically significant difference was observed (p=0.262) comparing the number of clinical cases in each subgroup with and without change in the incisal level. Conclusion: It was possible to conclude that the changes in the incisal level in maxillary anterior crowns retained by single implants in the adult patient were presented in 19.6% of the cases evaluated. This prevalence was not influenced by gender or age group; however, it was observed more often in dental implant cases with longer follow-ups. Schlagwörter: Facial growth, Anterior single implant, Esthetic, Incisal level

Purpose: This in vitro study aimed to compare by finite element analysis the stress distribution created in restoration components and the bone-implant interface by the effect of different abutment and crown esthetic material combinations. Materials and Methods: A model of an implant in the maxillary central incisor region was generated. 5 materials with varying moduli of elasticity (E) and 6 combinations were used for the crown and abutment to generate 6 models. The models’ abutment/crown materials were as follows: PEEK / lithium disilicate, PEEK / composite resin, hybrid ceramics / lithium disilicate, hybrid ceramics / hybrid ceramics, PEEK / hybrid ceramics, zirconia / lithium disilicate. A static load of 500 N was applied and structural analysis was started. von Mises (mvM) and principal stress values on the bone-implant interface and (mvM) values for cement lines, and restorative materials were evaluated separately. Results: All models had the same (mvM) distribution in the bone implant interface. Models with abutments having higher (E) values (zirconia and hybrid ceramics) showed lower (mvM) distribution in crowns and overlying cement than abutments with lower (E) values (PEEK). The model PEEK/composite showed the highest (mvM) in the crown and underlying cement while the model zirconia/lithium disilicate showed the lowest. Conclusions: Higher (E) values abutments showed better stress distribution compared to those with low (E) values. Clinical relevance: Restoring anterior dental implants with abutment materials having high (E) values is more successful than materials with low (E) values. PEEK abutment and composite crown showed significantly high stress in the cement between crown and abutment which might be a cause of debonding. PEEK abutments and composite crowns are not recommended for definitive hybrid abutments and crowns. Schlagwörter: dental implants, finite element method, high-performance polymer PEEK, zirconia, lithium disilicate, hybrid ceramics

Purpose: This study aimed to evaluate the relationship between risk profile assessments of dental implants that have been in function for at least two-year and peri-implant marginal bone loss during the follow-up period using the Implant Disease Risk Assessment Diagram. Material and Methods: A total of 70 patients and 170 implants who had been functionally loaded for at least two years and who attended follow-up sessions were included in the study. Full-mouth plaque index (PI), gingival index (GI), probing depth (PD), bleeding on probing, clinical attachment level (CAL), and peri-implant modified plaque index, modified bleeding index, PD, keratinized mucosal width (KMW), CAL and GR were recorded. According to the IDRA risk diagram, participants and dental implants were divided into low, moderate, and high-risk groups. Marginal bone level (MBL) was measured on periapical radiographs obtained at functional loading (T0) and at the last follow-up session (T1), and mesial and distal marginal bone level changes (ΔMBL) were calculated as T1-T0. Results: A statistically significant correlation was found between the periodontitis history and periodontitis susceptibility and IDRA classification at the patient-level. Full-mouth GI, PD, and BOP were found to be statistically higher in the high-risk IDRA group. No statistically significant result was found between the mesial and distal ΔMBL between the IDRA risk groups.Conclusions: In this study, IDRA risk level increased especially by periodontitis susceptibility and periodontitis history, but no significant difference was found between risk groups in terms of ΔMBL. Schlagwörter: periodontal disease; staging and grading; risk factors; disease susceptibility; periimplantitis, risk assessment

Primary failure of eruption (PFE) is a rare non-syndromic condition in which non-ankylosed teeth fail to erupt fully or partially due to malfunction of the eruption mechanism. 3 young patients are presented in this article with features consistent with a diagnosis of primary failure of eruption. The features of this condition are described together with different modalities of treatment planning for such patients. Zygoma implants as a new approach in the treatment of patients with primary failure of eruption requiring full mouth rehabilitation is discussed.

Purpose: Immediate implant placement is a reliable solution to replace hopeless teeth, but this procedure may be associated to an increased risk of soft tissue complications in case of thin biotype. The use of tissue-level implants with a convergent transmucosal profile has been advocated to increase space for soft tissue, contributing to improve their stability and esthetics. The aim of this retrospective study was to evaluate the esthetic outcomes and the Patient-Reported Outcome Measures (PROMs) of immediately placed implants with a convergent transmucosal profile. Materials and methods: This single-cohort, monocentric, retrospective clinical study was conducted on patients treated with an immediately placed implant in the esthetic zone (from premolar to premolar). All the eligible patients were recalled for a clinical and radiographic follow-up visit. Results: This study included 20 patients (8 males, 12 females) with an average age of 55.5± 6.8 years, who received 20 implants, with a mean follow-up of 46.5± 15.3 months. At the time of follow-up, immediately placed implants showed a mean Marginal Bone Loss of 0.42± 0.49 mm, and a statistically significant improvement of the esthetic parameters from baseline to the last available follow-up; in particular, Pink and White esthetic scores (p=.001) and Papilla Index at mesial and distal sites (p<.001). All the patients reported a high satisfaction (VAS>9) both from esthetic and functional point of view. Conclusion: Immediately placed implants with convergent transmucosal profile in the esthetic zone showed good clinical and esthetic outcomes, with stable results over time. Schlagwörter: Immediate placement, prostheses, cohort study, tissue-level

Purpose: This study aimed to investigate the associations between the concentrations of bone turnover markers and maxillary and mandibular cancellous Hounsfield units to determine whether bone turnover marker assessments are effective for preoperative examinations for implant treatment. Materials and Methods: The study included 94 patients (37 males and 57 females) with a mean age of 62.0±11.9 years. Spearman's rank correlation and multivariate linear regression coefficients were used to determine the associations between the bone turnover markers and maxillary and mandibular cancellous Hounsfield units. Results: Multivariate bias correction showed that the concentrations of bone-specific alkaline phosphatase, procollagen type I N-terminal propeptide, and deoxypyridinoline were negatively associated with the maxillary Hounsfield units. The concentration of undercarboxylated osteocalcin tended to be negatively associated with the maxillary Hounsfield units but not significantly. The concentrations of deoxypyridinoline and tartrateresistant acid phosphatase 5b were significantly negatively associated, and the concentrations of bone-specific alkaline phosphatase and procollagen type I N-terminal propeptide only tended to be negatively associated with the mandibular Hounsfield units. Conclusion: Several bone formation and resorption markers were negatively correlated with the maxillary and mandibular Hounsfield units. BTM measurement is effective for preoperative examination for implant treatment.

Aim: To assess the roughness and hydrophilicity of nine types of dental implant surfaces, while also examining the presence of contaminants carbon and oxygen on these surfaces. Furthermore, the study investigated potential correlations between these characteristics across the analyzed surfaces. Materials and Methods: The surfaces analyzed were as follows: MI: machined (turned), Implacil implant; TOI: blasted with titanium oxide, Implacil implant; TOAEI: blasted with titanium oxide and acid-etched, Implacil implant; ZAED: blasted with zirconia and acid-etched, DSP implant; CPD: coated with calcium phosphate, DSP implant; XD: subjected to an experimental treatment (patent pending), DSP implant; DAEHAS: double acid-etched and activated with hydroxyapatite nano-crystals, SIN implant; DAES: double acid-etched, SIN implant; and AMP: untreated surface of the Plenum implant, produced by additive manufacturing. Four and five disc-shaped specimens were used in the hydrophilicity and roughness assessments, respectively. Roughness was evaluated by optical profilometry and scanning electron microscopy; hydrophilicity was determined using the sessile-drop technique; and the chemical analysis was performed using X-ray photoelectron spectroscopy. The Kruskal- Wallis, Mann-Whitney, and Spearman correlation tests were employed to analyze the data (p < 0.10). Results: Significant differences were observed among the analyzed surfaces in terms of both roughness and hydrophilicity (p < 0.001). The surface exhibiting the highest roughness was AMP, whereas the greatest hydrophilicity was exhibited by CPD. Correlations between roughness and hydrophobicity were observed for MI (r = 0.936, p = 0.009), ZAED (r = 0.957, p = 0.004), and DAES (r = 0.964, p = 0.005). The carbon concentration observed on the CPD surface was lower than that observed on the other surfaces, whereas the oxygen concentrations were similar. No correlations were observed between the presence of contaminants and the roughness or hydrophilicity characteristics. Conclusion: Roughness and hydrophilicity values exhibited considerable variation among the tested surfaces. Aside from the CPD surface, comparable concentrations of carbon and oxygen were detected. Although correlations between roughness and hydrophilicity were observed only for the ZAED, DAES, and MI surfaces, these correlations were inadequate to establish a causal relationship between the two surface characteristics. Schlagwörter: Dental implants; Wettability; Osseointegration; Surface properties; Cell adhesion

Purpose: The osseointegration in dental implants is greatly affected by various surface properties, such as chemistry, texture, and overall cleanliness. This study aimed to investigate the impact of mineral oil lubricants used in rotary instruments on osseointegration within rabbit tibiae, with a specific focus on potential contamination from dental handpices. Materials and Methods: Twelve New Zealand rabbits were included in this study, each receiving two implants in each tibia, resulting in a total of 48 implants across the study. Groups were organized based on the time until euthanasia and the degree of implant contamination. Three contamination levels were defined: the first group received implants without any lubricant in the handpiece (control group); the second group received implants with handpices managed as recommended; the third group had implants placed using fixtures pre-soaked in lubricant. These groups were further subdivided based on euthanization periods of two and four weeks. We measured and analyzed both the removal torque and the bone-implant contact. Results: We observed a non-significant inverse correlation between the severity of fixture contamination and removal torque. However, there was a significant reduction in bone-implant contact associated with higher contamination levels, particularly after four weeks. Conclusions: Even brief exposure to lubricants from handpieces can jeopardize the osseointegration of implants in bone. Therefore, it is imperative to implement thorough procedures for lubricant removal post-application and to employ precise cleaning and suction during implant drilling and placement to minimize residual oil on the implant surface. Schlagwörter: Dental implant, osseointegration, lubricant, surface contamination

Purpose: To evaluate the efficacy of vertical guided bone regeneration (GBR) in the mandible utilizing a non-resorbable membrane and a bone graft combination of autogenous bone chips, and high-temperature processed (HTP) xenograft, through CT scans and microCT analysis. Materials and Methods: Patients underwent vertical ridge augmentation procedures prior to implant placement. The surgical procedure included flap elevation and placement of a bone graft comprising a 1:1 combination of autogenous posterior mandible-derived bone chips, and HTP xenograft graft particles covered with a d-PTFE membrane trimmed to suit the 3D shape of the bone defect. This was fastened securely with titanium screws and pins, and a layer of native collagen membrane. Post-operative complications and ridge measurements were assessed. Pre bone augmentation and pre implant placement bone parameters were obtained from CT scans. Biopsy specimens collected during implantation were examined by microCT. Results: All 13 study procedures were successful without any complications. The results revealed average vertical and horizontal bone gains of 3.35 mm and 5.15 mm respectively. A total of 33 implants were successfully placed in the augmented areas, without the need for further bone augmentation. MicroCT analysis revealed 48% bone, 15% filler material, and 37% non-calcified tissue in the augmented region compared to 65% bone, 3% filler material, and 32% non-calcified tissue in the pristine bone. Conclusions: A mixture of autogenous bone and HTP xenograft, covered with a d-PTFE membrane and a layer of native collagen membrane is effective for vertical GBR. Schlagwörter: vertical guided bone regeneration, microCT, xenograft, d-PTFE, GBR

Purpose: The purpose of this in vitro study was to evaluate the effect of titanium base height on torque loss of monolithic zirconia, lithium disilicate, and polymer-infiltrated ceramic hybrid- abutment restorations for offset placed implant. Materials and methods: Forty-two hybrid- abutment restorations supported by offset placed implants (diameter: 4.2 mm; length: 10 mm) were divided into 6 groups: short titanium base and zirconia (SZ), long titanium base and zirconia (LZ), short titanium base and lithium disilicate (SE), long titanium base and lithium disilicate (LE), short titanium base and polymer-infiltrated ceramic (SP), and long titanium base and polymer-infiltrated ceramic (LP). An adhesive resin cement was used to bond the restoration to the titanium base. The restoration was secured with titanium screw tightened to 30 Ncm by using a calibrated torque meter device. The specimens were exposed to thermocycling (5000 cycles at 5°C to 55°C), then cyclic loaded (120 000 cycles/50 N/1.6 Hz), where the load was placed vertically in mesial fossa of the restoration. After the loosening torque value of the abutment screw was measured by the torque meter device, the torque loss and its percentage were calculated. Two-way ANOVA, one-way ANOVA, and post hoc Tukey tests were used for statistical analysis of the data (α=.05). Results: The 2-way ANOVA test showed significant differences in loosening torque, torque loss and percentage of torque loss across the restorative material (P<.001), no significant difference across the height of titanium base (P=.213) and no significant interaction (P=.845) between restorative material and height of titanium base. Regarding the restoration type, 1-way ANOVA test showed significant difference (F ratio=15.95, P<.001) in torque loss between groups. The mean torque loss value with monolithic zirconia was significantly higher than with lithium disilicate (P=.039) and polymer-infiltrated ceramic (P<.001), respectively. Between the lithium disilicate and polymer-infiltrated ceramic, a significant difference (P=.013) was also found. Conclusion: The restorative material had a major effect on the torque maintenance in hybrid-abutment-restoration supported by offset placed implant, while the titanium base abutment height had no influence on it. Compared to lithium disilicate and polymer-infiltrated ceramic materials, monolithic zirconia induced higher torque loss when used as hybrid-abutment-restoration. Schlagwörter: torque loss, implant, titanium base, ceramic, abutment height

This technical note serves as a practical guide for clinicians aiming to provide solutions to optimize the precision of static computer-assisted implant surgery (sCAIS) and the success of implant placement in free-end situations. Five methods are introduced for enhancing surgical guide stabilization and improving the accuracy of implant placements in situations lacking stabilizing adjacent teeth. Techniques include the use of keratinized soft tissues, implant-borne stabilizers, lateral fixation pins, transitional implants, and digital bone segmentation for guide support. Each method is evaluated for its potential to address the specific challenges faced in sCAIS, aiming to contribute to the field through practical solutions for clinicians.

Purpose: The objective of this study was to examine how the saline and acidic environment affects the mechanical integrity of narrow single-body titanium implants for oral rehabilitation. Materials and methods: Thirty titanium-base alloy implants with 2.5 mm diameter were placed into a polyacetal holder and coupled to a stainless-steel prosthetic cap for fatigue testing in three different environments, as follows: dry air; saline solution (pH at 7.6); and lactic acid solution (pH at 3.4). The fracture surfaces were analyzed using a Scanning Electron Microscope (SEM). Also, finite element analysis was carried out to estimate the maximum von Mises stresses. Results: The fatigue resistance was higher in the group tested in dry air (60%), followed by saline solution (30%) and lactic acid (10%). Regardless of the environment, fracture occurred at the same region of the failed specimens in line with the highest stress concentration spots, according to the finite element analysis. SEM analyses revealed two distinct failure regions, both with the presence of fatigue streaks: fatigue and overload. A high incidence of secondary cracks was also noticed on the specimens exposed to the solutions. Conclusions: The present study revealed that both saline and acidic solutions significantly affect the fatigue resistance of narrow dental implants. Critical regions of the narrow implants were also susceptible to cracks and plastic deformation that should be taken into consideration in planning for oral rehabilitation.  Schlagwörter: extra narrow implants; fatigue; corrosion; saline solution, failure analysis.

Purpose: This study was designed to evaluate the influence of utilizing Polyetheretherketone (PEEK) coping and three different dental restorative materials in the success of tooth and implant-supported fixed partial dentures (TISFPD) in the maxillary posterior region, under static loading by 3-Dimensional Finite Element Analysis (3D FEA). Materials and Methods: Six 3D FEA models were designed assuming the extraction of maxillary first and second molars. Bone, implant, abutment, PEEK coping, second premolar, periodontal ligament (PDL) and six 3-unit TISFPD with different restorative materials [Porcelain-Fused-to-Metal (PFM), PEEK-Composite (PC), Monolithic Zirconia (MZ)] were modeled. Then, PEEK copings were modeled to be cemented onto the implants as a double-crown system for the first three groups (PFMPEEK, PCPEEK and MZPEEK) whereas, the next three groups (PFM, PC, MZ) excluded a PEEK coping in their designs. The prostheses were loaded twice, vertically and obliquely. From the determined points, 250 N for vertical loading (0o to the long axis) and 200 N for the oblique loading (30o to the long axis) were applied. Von Mises tension, maximum and minimum principal tension value criterias were analyzed. Results: Regardless of the material used for suprastructure, the maximum average stress was reduced by using PEEK coping. Considering the maximum stress distribution, PC appeared to have the highest stresses on the cortical bone, implant and screw. Additionally, the von Mises stresses formed in the PDL for each model were lower when PEEK coping was included in the design of the TISFPD, reducing the risk of intrusion. Conclusions: The stress distribution was positively affected by the PEEK coping in TISFPD design, reducing bone resorption and failure. This elastic material used generated lower stresses in the bone and implant, while no significant effect was found on stresses around natural teeth. Schlagwörter: Tooth-implant; PEEK; FEA; Stress distribution; Static loading

Objective: To observe and analyse patients with dental implant fracture and explore the factors influencing the fracture with the aim of providing reference for physicians’ clinical work. Methods: The clinical data of 19 patients with dental implant fracture who visited the Department of Implantology of our hospital between 2007 and 2019 were retrospectively observed and analysed, and the fracture’s influencing factors (e.g. the fracted implant site, implant diameter and connection mode, upper prosthetic method and fracture site) were analysed and investigated. Results: The fractured implants comprised 12 Straumann implants (5 fractured at the smooth dental neck and 7 atop the central screws), 5 Bego implants (4 fractured at the smooth dental neck and 1 atop the central screw), 3 Lifecore implants fractured atop the central screws and 1 Anthogyr implant fractured atop the central screw. Of the 19 patients, 6 had anterior dental implant fracture, and 13 had posterior dental implant fracture (21 fractured implants in total). Maxillary anterior dental implant fracture was observed in 6 patients (8 implants), maxillary posterior implant fracture was observed in 3 patients (3 implants), and mandibular posterior dental implant fracture was observed in 10 patients (10 implants). Conclusions: A good implant system design, appropriate implant diameter and reasonable upper prosthetic method are key to maintaining long-term stability of a dental implant.  Schlagwörter: Dental implant; implant fracture; implant diameter; Cantilever fixed bridge

Purpose: To investigate residual debris within internal features of new “as received” dental implants. Materials and Methods: A total of 15 new dental implants representing various dental implant brands were obtained in sealed containers from the manufacturers. Batch numbers and implant types were documented. In a controlled setting, implants were carefully unpacked, and their internal aspects were visually examined. Further analysis involved light microscopy imaging to document and photograph any foreign material. The internal aspect of the implants were sampled with both an endodontic paper cone and a fine bristle brush swab. These were inserted into the implant, rotated three times, then removed and examined under a microscope at 30x magnification. Post sampling some of the brushes/swabs were washed with alcohol to remove debris that could be further examined under magnification. Results: Inspection of the implants without magnification revealed no visible foreign materials. However, under light microscopy (x10 and x30), all 15 implants exhibited small black particles at various internal sites, including connections, threads, and deep within screw channels. Swabs evaluated at magnification detected what appeared to be metal particles in all 15 implants, ranging from distinct metal shards to smaller particles. Conclusion: This study suggests that implant manufacturers have not effectively removed all machining debris from within implant bodies, potentially producing prosthetic and clinical complications.

Purpose. There are several factors that may influence implant site preparation with implant design being a paramount factor; however, few studies investigate its impact. The purpose of the study was to explore the comparative efficacy of using two different drilling protocols using burs with different design for preparing implant sites, by evaluating radiographic and clinical outcomes. Materials and Methods. The present randomized controlled clinical trial with an allocation ratio of 1:1 was carried on in two private practice offices by two experienced surgeons and researchers. In the control group the surgeons followed the protocol with standard straight burs while in the test group they used step burs. In both groups the patients received the same type of implants and prosthesis. The primary outcome was the marginal bone resorption one year after the prosthetic placement. Results. In the study were included and treated a total of 60 subjects (86 implants). At the one-year follow-up were screened 54 subjects (74 implants), and 50 at the 2-year follow-up (69 implants). This study showed no evidence of a difference in bone resorption, which increased significantly over time, between the two groups. Conclusions. Both clinical parameters and patientcentered outcomes revealed no difference between the two protocols of implant site preparation with two different drill shape. Schlagwörter: Dental implant, bone surgery, osteotomy, implant bur design, marginal bone resorption, success rate, quality of life.

Objectives: Several anatomical and histological limitations can complicate implant placement, angulated implant positioning appeared to compensate these limitations. However several studies suggested a higher rate of marginal bone loss and implant failure regarding tilted implants in comparison with conventional implant. Therefore this umbrella review aims to summarize and analyze all the evidence available concerning marginal bone loss and implant failure between tilted and axial implants. Methods: An electronic literature search was conducted, without any language restrictions and only systematic reviews with meta-analysis or meta-analysis studies were included. The outcomes assessed in this review were implant failure and marginal bone loss in mm. Relative risks (RRs) and the differences of the mean (MD) were calculated with 95% confidence intervals (CIs) regarding implant failure and marginal bone loss respectively. Results: in total 8 studies were included, based on the short-term results, a non-significant mean difference (MD=0.00; 95% Cl; -0.01-0.02; p-value = 0.75) was recorded between tilted and axial implants supporting full-arch dentures, meanwhile a significant mean difference was recorded on a 3 years and long term follow-up reached (MD= 0.08 95% Cl = 0.05-0.11; p value<0.00001)) and (MD= 0.18; 95% Cl= 0.15-0.20; p value< 0.00001) respectively, and an insignificant difference was observed between tilted and axial implants regarding implant failure (RR=1.02; 95% Cl=0.85-1.23; p value= 0.81) Conclusion: this review based on high and moderated quality studies with low risk of bias demonstrated no significant outcome was observed between tilted implants supporting full-arch or fixed partial denture and axial implants regarding implant failure. Schlagwörter: Tilted implant; Axial implant; Dental implant; Marginal bone loss; Implant failure

Objective: To evaluate multiple risk factors of peri-implant bone loss. Materials and Methods: A case-control study was conducted on patients who had received dental implants treatment from January 2018 to December 2021. Implants with bone loss were included in the case group, and implants with no bone loss were included in the control group. Risk factors including history of periodontitis, abutment connection type, implant surface, diameter, location, three-dimensional position, opposing dentition, adjacent teeth, prosthetic type, retention type and custom abutment were evaluated. A multivariate logistic regression model was used to evaluate these risk factors, providing corresponding odds ratios (ORs) with 95% confidence intervals (CIs). Results: A total of 776 implants in 479 patients were included in the analysis. The number of implants in the case group and the control group were 84 and 692, respectively. Cement-retained prostheses (OR=2.439, 95%CI=1.241-4.795) and nonplatform switch design (OR=2.055, 95%CI=1.167-3.619) were identified as weak risk factors. Horizontal deviation (OR=4.177, 95%CI=2.265-7.703) was a moderate risk factor. Vertical deviation (OR=10.107, 95%CI=5.280-19.347) and implants located in the mandibular molar region (OR=10.427, 95%CI=1.176-92.461) were considered high risk factors. Conclusion: Implants in the molar region, cement retained, non-platform switch design, and poor three-dimensional implant positioning are identified as significant risk factors for peri-implant bone loss. Schlagwörter: Peri-implant bone loss, dental implants, abutment design, logistic regression

Purpose: As the population gets older, the prevalence of complete or partial tooth loss is increasing, significantly impacting people's quality of life. Scientific research demonstrates that implant-fixed complete dentures offer high levels of satisfaction. In certain cases, tooth loss can lead to significant bone atrophy, necessitating pre-implant bone reconstruction. We conducted a retrospective cohort study involving 43 arches, including or not bone grafts, rehabilitated using a stackable guided approach, which included an immediate loading protocol. The primary outcome measure was the survival rate of the implant at 4 months. Material and methods: The digital workflow helps the design of the provisional prothesis before the implant surgery, which will be loaded immediately after the implant's placement. The stacked guides integrate both surgical and prosthetic considerations into a digital workflow. Result: A total of 284 implants were placed. After a 4-month follow-up period, 10 implants (3.5%) exhibited no osseointegration and were subsequently replaced, resulting in an overall success rate of 96.5%. After 1 year of follow-up, a prosthetic success rate of 100% was observed, with all patients being able to progress to the stages for the permanent fixed dentures. Conclusion: Our findings support the use of this protocol for all patients, whether they require bone grafts or not. However, a long-term follow-up is essential for a comprehensive evaluation of these treatment outcomes. Schlagwörter: Complete edentulouComputer-guided surgery, Immediate loading , Stackable guide, Full Arch rehabilitation, Autologous Bone graft.

Purpose: To evaluate the effect of osteotomy preparation technique and implant diameter on primary stability and bone-implant interface of short implants (6mm), when placed in bone with high degree of cancellous content. Material and method: 90 short (S) implants (6 mm) divided in nine groups based on width (Narrow 4.2 mm, Regular 4.8 mm, Wide 5.4 mm) (N,R,W) and osteotomy preparation (Standard, Osteotome, Osseodensification) (ST, OT, OD) and placed in porcine tibia plateau bone samples: Group SN-ST; Group SN-OT; Group SN-OD; Group SRST; Group SR-OT; Group SR-OD; Group SW-ST; Group SW-OT and Group SW-OD. Insertion torque and Implant Stability Quotient (ISQ) were measured. Four implants from each group SNST, SN-OT, SN-OD were evaluated histomorphometrically. Results: Insertion torque was significantly higher for implants of Group SW-OD compared to Group SW-ST (50.00 ±14.14 Ncm vs 28.00 ±10.85 Ncm, p= 0.005) and Group SW-OT compared to Group SW-ST (46.87 ±17.10 Ncm vs 28.00 ±10.85 Ncm, p=0.026). Insertion torque was significantly higher for implants of Group SW-OD compared to Group SN-OD (50.00 ±14.14 Ncm vs 31.5 ±15.82 Ncm, p=0.04). No significant differences were observed for the percentage of bone, marrow space and connective tissue in contact to the implant surface between studied groups. Conclusion: Osteotomy preparation technique at sites with high degree of cancellous content can influence the implant insertion torque for short and wide implants (5.4x6mm). Implant width can influence the insertion torque of short implants placed with the osseodensification technique. Schlagwörter: Osseodensification, osteotome, stability, implants, histology, bone

Despite high rates of success for dental implants, implant failure due to several causes may require explantation. In the present retrospective study, implants removed between 2000 and 2022 have been registered and the cause of removal has been established. All implants were removed by a single operator (PPM) in the department of Oral Surgery of the George Eastman Dental Hospital in Rome, Italy. Characteristics of removed implants such as implant surface, morphology (bone versus tissue level implants), type of restoration (fixed versus removable), in the case of fixed restorations, mode of retention (cement versus screw-retained), location of the implant (maxillary versus mandibular arch) were recorded. Furthermore, patient-level characteristics were also recorded (systemic health conditions and medications taken, smoking habits and previous history of periodontitis). In total, 381 implants in 381 patients were removed in the 20-year time-span. The most frequent cause of removal was peri-implantitis (82.4% of implants), followed by implant malposition and loss of osteointegration. The survival time was not affected by the cause of removal, while bone level implants had a longer survival time versus tissue level implants. Maxillary implants had a higher prevalence of peri-implantitis compared to mandibular implants.

Purpose: To retrospectively evaluate the long-term clinical, technical, biological, and esthetic outcomes of implant supported single zirconia crowns (ISCs) intraorally cemented to Ti-base hybrid-abutments up to 16 years after placement. Materials and Methods: A total of 63 ISCs (Xive S, Camlog Screw Line, Replace Select TC NP, Branemark MK II, and 3i Osseotite) were evaluated in 36 patients at two different centers. Original Ti-bases were selected and zirconia meso structures and zirconia crowns were designed using CAD/CAM software and then milled from partially stabilized zirconia blocks. After the meso structures were cemented extraorally onto the Ti-bases, the ceramic crowns were intraorally luted to the hybrid abutments. The Ti-base ISC restorations were followed up for up to 16 years, and their clinical, biological, and esthetic outcomes were recorded at distinct time points (T1; T2) at three-year intervals. Results: 36 patients (18 men, 18 women) received 32 ISCs in the anterior region and 31 in the posterior region of the maxilla and mandible. The mean follow-up of the Ti-base ISCs was 6.93 ± 2.60 years. The mean follow-up of the implants amounted to 8.11 ± 3.26 years. No implants were lost during follow-up, resulting in a cumulative implant survival rate of 100%. Abutment screw loosening was observed in two ISCs after one year in service. The overall cumulative restorative survival rate of the Ti-base restorations reached thus 96.83%. At T2 follow-up 24% of the ISCs exhibited an increase in PD despite maintaining clinically healthy peri-implant tissue. An 11% increase in BOP and a 3.17% decrease in PI were recorded. Despite spectrophotometrically measured ΔE values indicating visible discoloration of some restorations and their peri-implant soft tissue, a low incidence of esthetic complications was observed with an average PES/WES score of ≥ 12. No correlation was found between PES (R = -0.25; p = 0.27) and WES (R = -0.18; p = 0.43) scores and digital shade determination. Conclusions: The results of the present retrospective, multicenter, cohort study indicate satisfactory clinical outcomes for intraorally cemented single zirconia crowns (ISCs) supported by Ti-base hybrid abutments. An overall esthetic superiority of Ti-base ISCs could not be confirmed. Schlagwörter: retrospective trial, titanium base, zirconia, two-piece hybrid abutment, implant-supported single crown.

Purpose: The aim of this study is to examine the stresses on the peri-implant bone under occlusal forces of 30% Carbon fiber reinforced PEEK (Cfr-PEEK) and 60% Cfr-PEEK materials that can be used as an alternative to titanium dental implants by finite element analysis. Materials and Methods: Single-tooth implants of 30% Cfr-PEEK, 60% Cfr-PEEK and titanium were modeled in each of the maxillary anterior, maxilla posterior, mandibular posterior regions. As a result of the applied vertical and oblique forces; Von Misses stress, maximum principal stress and minimum principal stress values and stress distributions in the implant, cortical bone and spongious bone in each of the models were examined. Results: 30% Cfr-PEEK implants stress in the surrounding bone was higher than titanium and 60% Cfr-PEEK implants. The 60% Cfr-PEEK material displayed lower stress distribution on both cortical and spongious peri-implant bone in all models. Conclusion: Titanium and 60% Cfr- PEEK implants exhibited biomechanically similar behavior and these implants conducted stresses to bone more homogeneous than the 30% Cfr-PEEK implants. Overall, oblique forces had more destructive effect than vertical forces and denser bone structure showed better stress distribution against incoming forces. For the routine use of Cfr-PEEK material as dental implant material; animal and long-term clinical studies are needed. Schlagwörter: Carbon fiber reinforced PEEK, Finite element analysis, Dental implant

Purpose: Severe anterior maxillary atrophy offers few implant-supported rehabilitation solutions to Quad Zygoma characterized by a wide anterior cantilever. One of the possible alternatives to consider before the quad zygoma is the extra-long nasal/trans-nasal implant placement. This retrospective multicentric study shows the predictability of nasal/transnasal implant placement in patients affected by severe anterior maxilla atrophy, with residual anatomical features that indicate this surgery. This specific remote anchorage can often be safely involved in immediate loading with other remote anchorages, such as zygoma and pterygoid implants. In this rehabilitation, it’s mandatory to reduce the instability of the frameworks and mechanical stress that could unfavorably affect the implant's prognosis due to the overloading derived from anterior bending. Materials and  Methods: In this retrospective multicentric study, 52 nasal or trans-nasal implants were inserted in 31 atrophic anterior maxillas (Cawood and Howell's class V-VI). All implants were successful after the healing period; even if 27 nasal implants reached an insertional torque equal to or greater than 50 n/cm2, the threshold value estimated to be able to support an immediate load. Result: All 52 implants were successful, so the proportion of success was 100%, with a 97.5% one-sided confidence interval of 88.8-100%. The success rate is achieved only if at least two of the following criteria are met: 1) a greater torque than 50 Ncm as a minimum sufficient condition to plan immediate loading; 2) after a healing period of 16 weeks, the secondary stability is clinically and radiographically evaluated to exclude possible coronal bone resorption: this condition allows the successive prosthetic finalization; 3) the possibility of carrying out a full arch rehabilitation with minimal anterior spread. Insertion torque was <50 Newton centimeters (Ncm) in 14 patients (45%) and 50 Ncm in 17 (55%). Mechanical load was delayed in the former and immediate in the latter. The proportion of torque <50 Ncm was higher in men than in women (69% versus 28%, p=0.033). Immediate torque was not significantly affected by age. Conclusion: Although the sample is not extremely numerically significant, it conveys a clear and significant clinical, surgical indication as never before in the literature; we can state that nasal/trans nasal implants have been very useful in reducing the anterior cantilever and overcoming the anatomical limitations affecting conventional Quad Zygoma. Schlagwörter: nasal implants, zygomatic implants, pterygoid implants, anterior cantilever prostheses, severe atrophy

Purpose: Compare Neodent Zi® zirconia implants' insertion torque (IT) and removal torque (RT) with Neodent Alvim® titanium. Measure the maximum torque supported by the zirconia implant until its fracture (MT) and the maximum torque sustained by the assembler of this implant (MTA) until its fracture. Material and Methods: In this in-vitro study twenty four implants were used. Two groups of implants with the same macrogeometry and from the same manufacturer were compared, Zirconia (n=12) and Titanium (n=12). Implant bed preparations were completed in bovine ribs following a standardized drilling protocol. Then, the insertion torque (IT), removal torque (RT), maximum torque to fracture (MT) and maximum torque to fracture of the assembler (MTA) were completed using a calibrated torque meter. Data was presented using descriptive statistics including means, standard deviations (SD), medians, and quartiles. The Shapiro-Wilk test was used to verify data normality and the Wilcoxon test was used to evaluate differences between groups. Statistical significance was established as p < 0.05. Results: Zirconia implants showed: IT 89.33 ± 31.18 Ncm and RT 84.89 ± 32.92 Ncm. Titanium implants showed: IT 77.58 ± 28.96 Ncm and RT 76.75 ± 31.29 Ncm without significant differences (p>0.05). In relation to fracture under rotational force, the zirconia implants fractured at 106.17 ± 22.54 Ncm, and the implant assembly fractured at 84.00 ±13.14 Ncm. Conclusion: Neodent Zi® implants showed stability but lower fracture torque than Alvim® titanium. As the fracture values of the assembler were significantly lower than the fracture values of the zirconia implants, it can be stated that, as recommended by the manufacturer, they act as a safety measure during installation. Schlagwörter: Biomechanical phenomena, fracture strength, Y-TZP ceramic.

Purpose: The successful osseointegration around immediate implants requires high quality and quantity of osteogenesis around them. The role of magnesium as a boneenhancing mineral, and as an adjunctive analgesic has been well documented in orthopedic literature. However, there is a paucity of literature in its role in successful osseointegration around immediate implants. This randomized controlled trial sought to assess the promising impact of magnesium on osseointegration by examining various aspects of implant stability, correlating them with serum bone markers, and establishing a foundation for future research on its potential as a potent analgesic. Materials and Methods: Immediate implant placement was done after the extraction of the indicated mandibular molar tooth, and all the patients were segregated into 2 groups (Placebo- Lactose, and Magnesium citrate). Bone regenerate in the peri-implant area was assessed radiographically immediate post-operatively, on the 6th week and 12 weeks. Implant stability was measured immediate post-operatively, at the 4th week and 12th week. Serum parameters were procured pre-operatively and post-operatively for serum calcium, serum alkaline phosphatase (ALP), and serum parathyroid hormone at the 8th week, and serum vitamin D3 levels preoperatively. Results: 54 immediate implants placed showed the demographics and baseline serum, clinical, and radiographic parameters were comparable in both groups. Analysis of Implant Stability Quotient at 12th week showed statistically significant difference in intervention group both on intergroup and intragroup analysis. Radiodensity measurement showed a statistically significant difference in both intragroup and intergroup analysis in the intervention group at the 6th and 12th week. In bone gap analysis, the difference in mean change in the horizontal bone gap (HG) at 6 weeks was non-significant while the difference in HG at the 12th week was significant in the intervention group. On intragroup analysis, mean change HG at 6 weeks and 12 weeks both were significant only in intervention group. Intergroup analysis of vertical bone gap (VG) 12 and VG 12-0 (mean difference in the vertical bone gap from 12th week-day 0) showed a statistically significant difference in the intervention group. On intragroup analysis, VG 12 was significantly better in the intervention group. On serum analysis, ALP post-operatively was found to be significantly raised (P=0.013) in intervention group. Numerical rating Scale (NRS) analysis showed a significant decrease in post-op day 5 and 7, (P=0.017) and (P=0.002) respectively. Conclusion: The oral magnesium citrate supplementation after immediate implant placement helps in enhancing the stability of the immediate implants, along with improved radiodensity around them which was found to be statistically significant. It also helps in reducing the horizontal, and vertical gap around the implant and has significant analgesic potential. Schlagwörter: Immediate implant; Magnesium citrate; Implant stability quotient; Analgesia; Osseointegration

Purpose – Compare the morphometric results of immediate implants (Type 1C) with a cylindrical (conventional) or triangular neck, in the anterior region of the maxilla, during 6 months of osseointegration. Materials and Methods – Prospective randomized clinical trial with a sample of 20 individuals randomly assigned to each group (10 triangular neck implants and 10 cylindrical neck implants). Consecutively direct measurements were performed: before (T-1) and after tooth extraction (T0), after implant placement (T1), after 1 month of the submerged implant healing (T2), when placing the healing abutment (T3), after placing the definitive crown (T3), and after 6 months of osseointegration (T4). Results – A significant difference between T1 and T3 in the buccal cortical thickness was identified (0.49Å}0.86mm). Although there was a significant increase in the buccal cortical thickness in both implants, this increase was greater for the triangular neck implants (cylindrical shape: 0.08Å}0.59 vs. triangular neck 0.90Å}0.91mm). It was also observed that implants placed below the buccal bone crest (í-1mm) promote less vertical buccal bone loss than implants placed Ñ-1mm at crest level (-0.65Å}0.52mm vs. -1.42Å}0.86mm). This observation needs to be further investigated in additional studies. Conclusions – The triangular neck implants present an increase in the cortical buccal thickness compared to the cylindrical implants. However, this increase does not fully compensate the remodulation after tooth loss. Schlagwörter: dental implants, dental implant placement, single tooth, endosseous implant, esthetics, immediate dental implant placement.

Purpose: The objective of this systematic review and meta-analysis was to examine the impact of titanium base supported single implant restorations on peri-implant conditions. Materials and Methods: Six randomized controlled trials (RCTs), comprising a total of 274 implants that met the inclusion criteria, were chosen for data analysis. A random effects model was employed for the metaanalysis. Results: Data from this study revealed that the Ti-base group exhibited a slightly but statistically significant increase in peri-implant marginal bone loss (difference in means = 0.088, 95% confidence interval = 0.003 to 0.17, p = 0.041) compared to the one-piece-abutment group. These effects were consistent in the subgroup analysis of regular-threaded implants comparing to the microthreaded subgroup. However, no significant differences were observed between the Ti-base group and the abutment group concerning probing depth (PD), bleeding on probing (BOP), and the risk of prosthetic-related complications. Conclusions: The utilization of Ti-base in single-implant supported restoration is associated with a slight increase in peri-implant marginal bone loss, while other periimplant health parameters show no significant correlation. Therefore, to determine the impact of Tibase on peri-implant condition of single implant-supported restoration is insufficient based on the findings of this meta-analysis.

Purpose: To evaluate the response of human peri-implant soft tissue (PIST) on different healing abutment materials 24 hours after positioning, by assessing the expression of genes related to the early connective tissue wound healing response. Materials and Methods: Experimental abutments of 4 different materials (A): grade 4 titanium, (B) grade 5 titanium, (C) zirconia and (D) PEEK, were mounted on installed implants in 5 patients, four different abutments each. Before implant placement, a gingival biopsy (control-CT) was obtained using a 2 mm diameter punch (T0). After 24 hours (T24), PIST biopsies were collected using a specifically designed custom-made cutting device. Real-time PCR was performed to analyze the expression of the following genes: COL-I, COL-III, MMP-1, TIMP-1,TGF-b1, FN, ITGA4, ITGA5, ITGB1, RAC-1, COL-IV, aSMA, IL-6 and CXCL-1. Results: Gene expression analysis showed some differences between CT and abutment of different materials, although no significant differences were detected comparing the experimental groups. COL-I was significantly down-regulated in groups A and C compared to CT. MMP-1 and TIMP-1 increased in all the experimental groups, although at a lower extent in group A. FN, RAC-1, COL-IV and aSMA were down-regulated, especially in group A, in which CXCL-1 and IL-6 showed the lowest expression. Conclusions: The results of grade 4 titanium and zirconia abutments seem to be promising, since a lower expression of genes related with inflammation, myofibroblasts activation and ECM remodeling was observed when compared with grade 5 titanium and PEEK, without triggering a pro-fibrotic response in the early phases of PIST repair. Schlagwörter: gene expression analysis, PEEK, peri-implant soft tissue, titanium, zirconia, wound healing

Purpose: The purpose of this study was to analyze the effect of scanning modes on the accuracy of the Trios for full-arch digital implant impressions. Materials and Methods: The trueness and precision of the intraoral scanning mode (IOSM) and the intraoral edentulous scanning mode (IOEM) of the Trios were evaluated in three edentulous models, each featuring 4, 6, and 8 implant analogues. Reference scanning data were obtained by scanning each model with a desktop scanner. Each model was scanned 10 times using the IOSM and IOEM modes of the Trios to establish the test groups. The scan bodies in the test and reference scans were isolated and exported in the reverse engineering program. The scan bodies in each group were superimposed with the corresponding reference scan (trueness) or with each other (precision). The overall 3D deviation between the aligned scan bodies was computed by the root-meansquare (RMS) values. Results: As a result of the trueness and precision evaluation, no significant difference was found between scanning modes in any of the models. When comparing models, the 8-implant model showed significantly lower trueness than the 4-implant model. However, it also exhibited significantly higher precision when compared to both the 4-implant and 6-implant models. There were no significant differences in other pairwise comparisons between the models. Conclusion: Trueness and precision values were similar between the IOSM and IOEM groups across all the models. An increase in the number of implants in complete edentulous arches may have a negative impact on digital impression accuracy. Schlagwörter: Scanning mode, digital implant impression, intraoral scanner, full-arch

Objective: The present study aimed to compare and quantify the surface changes seen in two most commonly used orthodontic miniscrew implants (MSI) materials; titanium and stainless steel after their clinical use. Methods: 40 MSIs (20 titanium and 20 stainless steel) were retrieved from the maxillary arch of 20 subjects (13 females and 7 males) in the age group of 18 – 27 years (mean age=22.4 ± 3.83 years) after their intended use. 40 (20 titanium and 20 stainless steel) asreceived MSIs were used as control. All the MSIs were analyzed under a Scanning Electron Microscope (SEM) for the characterization of their morphological condition (blunting of tip, surface defects and corrosion). Furthermore, Energy Dispersive X-ray (EDX) microanalysis was carried out to study the changes in surface characterization. Results: When imaged using SEM, as-received Titanium and Stainless Steel MSIs demonstrated a relatively smooth surface with no surface defects. However, the retrieved titanium and stainless-steel implants showed increased surface defects (both corrosion and cracks) with the difference being statistically significant. The retrieved Titanium MSIs (115.31±24.38μm) showed 4 times more blunting compared to the retrieved Stainless-steel MSIs (29.74±8.56 μm), with the latter showing 2-3 times more surface corrosion. Conclusion: Clinical usage had pronounced effects on both Titanium and Stainless steel MSI alloys in terms of changes in the surface characteristics. While stainless steel MSIs are more susceptible to surface corrosion, Titanium MSIs exhibit greater alterations in the form of tipblunting and cracks in screw threads.

Purpose: This study aimed to assess the alteration in keratinized mucosa (KM) dimensions in the early healing period after implant placement, and the influence of variables obtained during implant surgery on KM alteration. Materials and Methods: Study participants were consecutively recruited from patients who had received implants following a non-submerged surgical protocol. The implant had to be installed in the extraction socket that had healed for more than 6 months without any soft or hard tissue augmentation. Keratinized mucosa width (KMW), keratinized mucosa thickness (KMT), soft tissue level (STL), and probing pocket depth (PPD) were measured at implant placement and 3 and 6 months after implant surgery. The influence of variables obtained during implant surgery on the 6-month KMW alteration was assessed. Results: A total of 66 implants in 55 patients who completed the follow-up examination after 6 months were included in this study. KMW, KMT, and STL significantly decreased at 3- and 6-months examination by 0.7–1.2 mm. KMW was reduced by 24.6%. Mesial PPD significantly increased between the 3- and 6-months follow-up. In the multivariate generalized estimating estimations analysis, the implant diameter negatively influenced the 6-month KMW alteration, but the KMW at implant surgery positively influenced the 6-month KMW alteration. Conclusions: The KMW decreased significantly at 3 and 6 months after implant placement. If the initial KMW was wider, the KMW was reduced more at 6 months after implant placement. Therefore, it is important to carefully monitor KMW alterations during the early healing period to ensure optimal esthetics and peri-implant tissue health. Schlagwörter: mucous membrane, dental implants, wound healing, humans, prospective studies

Natural Coral Particles (NCPs) are a suitable scaffold material for Guided Bone Regeneration (GBR) procedures; it combines the placement of a bone substitute supporting a barrier membrane. Due to increasing sea pollution and the declarations of endangered coral species (KYOTO 1997), they are no longer suitable for the medical industry. Novel domestic corals have been grown under controlled conditions to produce cultivated coral graft (CCG) material. This study aimed to evaluate a new CCG in an in vivo experimental GBR procedure. The calvarias of 8 rabbits were surgically exposed, and circular defects 8 mm in diameter were prepared. One defect was filled with CCG particles (experimental group); the contralateral defect (control group) was spontaneously filled by blood clot. The defects were covered with a collagen membrane. Animals were euthanized after 8 weeks. Histological observations of the defects showed similar bone growth patterns in both experimental and control osteotomies. In the experimental defects, no traces of coral particles were observed. Histometric analysis showed denser bone in the pristine zone (65-66%) than in the peripheral zone for both the control (50%) and experimental defects (31%) (P= NS). The new bone percentage was reduced from the peripheral zone toward the middle and the center of the defect (31%, 32% and 27%, respectively) as the distance from the peripheral pristine bone borders increased. The existing data support the complete degradation of CCG as space-maintaining scaffold for GBR procedures. Schlagwörter: coral, graft, animal study, GBR, bone, rabbit.

Purpose: Finite element analysis and an in vitro experiment were employed to investigate the loading effects of angled abutments, comparing various customized angled abutments derived from the average angle of incisors in patients with a commercial 15°∆ angled abutment, on both the implant and surrounding bone. Methods: Four customized angled abutment models (21.9°∆, 24.15°∆, 20.22°∆, 33°∆) were developed using cone-beam computed tomography (CBCT) images of incisor inclination from various age groups of patients. 3D maxillary bone models were created from CBCT images of four individual patients. Finite element analysis and in-vitro strain gauge experiments were conducted, applying 100N or 50N of axial or oblique force, to assess the differences in stress/strain between the customized and the commercial 15°∆ angled abutments in both the implants and surrounding bone. Results: Under axial loading, the stress values in the dental implant and surrounding bone were elevated due to the relatively higher angles of the customized angled abutments (21.9°∆, 24.15°∆, 20.22°∆, 33°∆) when compared to the commercial 15°∆ angled abutment; however, under oblique loading the commercial 15°∆angled abutment exhibited higher stress values in both the implant and surrounding bone. For in vitro experiment, there is no statically difference in bone strain between the customized (21.9°∆) and the commercial 15°∆ angled abutments in axial loading. Nevertheless, in oblique loading using a commercial 15°∆ angled abutment induced the higher bone strains. Conclusion: Customized angled abutments offer lower stress/strain under oblique loads but higher stress/strain under axial loads compared to commercial ones. Therefore, in the design and application of angled abutments, careful consideration of the occlusal load direction is paramount for achieving biomechanical success of dental implant. Schlagwörter: maxillary incisor region; immediate implant placement; customized angled abutments; finite element analysis; in-vitro strain gauge experiment.

Purpose: To evaluate, within a period of 5 years, the bone level in mesial, distal, palatal, and buccal areas around scalloped shape implants immediately placed and loaded with temporary crowns fixed on final prefabricated abutments, and also to evaluate the thickness of buccal bone. Materials and Methods: 18 implants were inserted and loaded immediately using computer-assisted design/computer-assisted manufacturing technology on 18 patients to replace single tooth in the esthetic part of the maxilla. The marginal bone level across the scalloped implant neck was measured mesially and distally using intraoral standardized radiographs after crown fixations and 1, 3, and 5 years later. Cone beam computed tomography para-axial cuts images were used to measure bone level buccally and palatally from the implant neck to the implant-to bone contact after 5 years of loading and to evaluate the thickness of the buccal bone at the implant neck and 4 mm apically, immediately after implant placement and 5 years later. Results: All implants were assessed clinically and radiologically after 5 years. No implant failure was recorded, and the average marginal bone variation on mesial and distal sites was 0.114 ± 0.135 mm at crown cementation, 0.239 ± 0.158 mm 1 year later, 0.233 ± 0.182 mm 3 years later, and 0.180 ± 0.182 mm 5 years later. Our findings indicate that at T0, the average thickness of the buccal bone was 2.27 mm at implant neck M0 (ranging from 1.9 to 2.4) and 2.33 mm at 4 mm apically to the implant neck M1 (ranging from 1.9 mm to 2.9 mm). By T4, the mean had decreased to 1.94 mm at M0 (with a range of 1.7 mm to 2.3 mm) and 2.14 mm at M1 (with a range of 1.8 mm to 2.4 mm). After 5 years the mean changes at buccal and palatal bone for all implants were +0.187 ± 0.52 mm and +0.06 ± 0.38 mm respectively. Minor prosthetic problems were observed over the five years: incisal ceramic chipping occurred in two crowns, and two crowns were replaced for esthetic reasons after one year. No loosening of crowns or abutments was reported. Conclusions: Scalloped neck implants demonstrated a comparable behavior to regular neck implants with similar designs in an immediate implantation and temporization protocol over a five-year period. Schlagwörter: immediate implantation, immediate loading, maxilla, scalloped neck, marginal bone level, buccal bone thickness, CAD/CAM.

Reducing crestal bone loss (CBL) around implants allows for soft tissue stability and long-term success. The aim of the present study was to evaluate the extent of CBL in implants placed with the implant shoulder at the equi-crestal level and 2 mm below the alveolar ridge at 2, 12, 36, and 60 months. A split-mouth randomized controlled clinical trial was conducted by selecting subjects with Kennedy Class IV partial edentulism of the lower jaw. Two implants were inserted, of equal length and diameter, one equi-crestal and the other sub-crestal, in the site corresponding to the lateral incisor. Intraoral periapical radiographs with Rinn centering devices were performed at the time of implant insertion (T0), at 2 (T1), 12 (T2), 36 (T3), and 60 months (T4). Descriptive statistics and the T-test were used, setting the significance to P⩽ 0.05. Twenty-five subjects were recruited, with a mean age of 65 years (SD 9.88, range 42-82). No subject dropped out. A total of 50 implants were inserted, 25 at crestal and 25 sub-crest level. At the 60-month follow-up, no implant or prosthetic failure was recorded. An average loss of -0.81 mm was recorded in the crestal implant group (n.25; SD: 0.40; max-min: -1.6 – -0.1) while in the implants positioned below the crest the average CBL was -0.87mm (n.25; SD: 0.41; max-min: -2 – -0.2); however, the higher CBL in the sub-crestal implant group was not statistically significant (P=0.65). Comparing the mean CBL values of the two groups at the various follow-ups, a greater crestal bone resorption was recorded in sub-crest implants between T0 and T1 (-0.25 vs -0.1) and between T1 and T2 (-0.39 vs -0.23), while in subsequent follow-ups a greater, statistically significant (P=0.01), crestal bone loss was recorded in ridge implants between T3 and T4 (-0.05 vs -0.18). Over time, therefore, the extent of CBL seems to be reduced in implants placed below the crest, with bone retention above the implant shoulder. Ultimately, although the position of the implant shoulder relative to the crestal ridge doesn’t affect the CBL, sub-crestal placement is recommended in order to reduce the risk of exposure of the rough surface of the implant. Schlagwörter: crestal bone loss, dental implant-abutment design, microthreads, Morse-taper connection, dental radiography, dental implant platform switching, sub-bone level.

Purpose: One-size implant-abutment (OSIA) connection systems have been developed for simplicity of clinical use and for a range of implant diameters. The aim of this in vitro study was to investigate the rotational load fatigue performance of different implant diameters and abutment platforms of an OSIA connection system. Methodology: Narrow, regular and wide diameter implants were tested with Regular Base (RB/WB) abutments of an OSIA system (Straumann. BLX). Wide diameter implants were also tested with Wide Base (WB) abutments. This resulted in 4 test groups (n=5): N-RB/WB (Narrow, 3.5mm, RB/WB abutment), R-RB/WB (Regular, 4.0mm, RB/WB abutment), W-RB/WB (Wide, 5.0mm, RB/WB abutment) and W-WB (Wide, 5.0mm, WB abutment). A rotational load fatigue machine applied a sinusoidally varying stress at an angle of 45o, producing an effective bending moment of 35Ncm at a frequency of 10 Hz in air at 20 oC. The number of cycles to failure was recorded. Results were evaluated using ANOVA. Failed specimens were examined with SEM to evaluate the failure mode. Pristine specimens were sectioned to examine the implant-abutment connection. Results: All specimens in the 3 test groups with RB/WB abutments failed within the range of 558,750 cycles to 4,497,619 cycles, while the W-WB test group reached the upper limit of 5 million cycles without failure. Significant difference was found between abutment platforms (P < .001). There were no significant differences found for implant diameters (P =.857). However, with increasing implant diameter, implant fracture was less common and the location of failure was more coronal and consistently at the level of the implant platform for the abutment, and at the screw neck. Conclusions: For wide diameter implants, WB abutments exhibited a superior fatigue performance than RB/WB abutments, and would be preferred in situations of high mechanical risk. Increasing implant diameter, when used with RB/WB abutments, did not improve fatigue performance due to the one-size prosthetic connection, but failures were less catastrophic, and coronally located, which may be advantageous in managing failures. Schlagwörter: Keywords: Failure Analysis, Load Fatigue, Implant-abutment Connection, Implant Fracture

Purpose: Following tooth extraction, the healing process comprises bone resorption and soft tissue contraction, which have the potential to obstruct the optimal placement of implants, causing both functional and aesthetic limitations. This study is aimed at assessing the healing process of the extraction socket and the dimensional changes that occur after alveolar ridge preservation, utilizing a polylactide-co-glycolide scaffold (PLGA). Materials and method: The present study involved the extraction of 28 teeth from 14 patients. The total number of sockets was 28, which were divided into two groups consisting of 14 study and 14 control sockets. The study group (SG) was subjected to socket preservation with PLGA scaffold while the control group (CG) was left for spontaneous healing. Measurements were taken before and after the operation, with cone beam computed tomographies (CBCT) being conducted at both the baseline and 4-month intervals. Samples for histological examination were obtained via trephine core biopsy and the implants were subsequently placed. Results: According to the histologic analyses, the PLGA scaffold was resorbed within four months. CBCT imaging revealed a decrease in the horizontal dimension of the crest at three distinct coronoapical levels in the SG, measuring 2.05±1.05 mm at -1 mm, 1.51±0.89 mm at -3 mm, and 0.92±0.7 mm at -5 mm level. The CG showed readings of 1.22±1 at -1 mm, 0.92±0.67 at -3 mm, and 0.73±0.69 at -5 mm levels. In comparison to CG, SG showed a significant reduction in horizontal losses at the -1 mm level. Vertical dimension of the crest decreased by 1.64±1.11 mm on the buccal bone height, 1.56±1.08 mm on lingual bone height in SG; in the CG, the buccal and lingual bone height had mean values of 2.08±1.44 mm and 1.73±1.27 mm, respectively. There was no significant statistical difference observed in the vertical losses between the groups. Conclusions: Following a period of 4 months, it can be concluded that the PLGA scaffold was completely resorbed. Based on CBCT measurements, it was observed that horizontal resorption was lower than CG at the -1 mm coronal level. Schlagwörter: alveolar bone resorption, socket preservation, polylactide-co-glicolide acid, cone beam computer tomography

Background: The use of ceramic-coated patient-specific CAD/CAM titanium abutments represents a therapeutic option for the rehabilitation of single tooth. The utilization of highly customized abutments enables the accurate three-dimensional positioning of the prosthetic emergence. This study evaluates the clinical performance of implant-prosthetic rehabilitations carried out using ceramic-coated CAD/CAM titanium abutments. Materials and methods: Thirty implants were placed in thirty patients and rehabilitated with thirty single crowns attached to CAD/CAM titanium abutments. A conventional procedure was applied, with implant placement after post-extraction socket healing and prosthetic restoration after implant healing. Implants of lengths ranging from 6-15 mm and widths of 3.6, 4.2, and 4.8 mm were used in this study. At the time of prosthesis delivery (T0), after two years (T1), and after five years (T2), plaque (PI) and bleeding (BoP) indices, probing depths (PPD), marginal bone levels (MBL), and PES/WES were evaluated for each implant. Results: No patient dropped out of the study during the follow-up period. All thirty implants were clinically successful at five years post-prosthesis delivery (survival rate: 100%) and showed no signs of peri-implant infection. Peri-implant soft tissues were in good health (BoP at T2: 0% in 73% of patients; 25% in 13% of patients; 50% in 10% of patients; and 75% in 3% of patients). The mean PPD was 2.05±0.56 mm at T0, 1.992±0.6 mm at T1, and 1.867±0.439 mm at T2. The mean MBL at T0 was 0.413±0.440 mm, at T1 was 0.306±0.388 mm, and at T2 was 0.263±0.368 mm. The mean PES, WES, and PES/WES indices, 7.43±1.04, 7.57±0.82, and 15.00±1.17, respectively, indicate good integration of soft tissues, satisfactory aesthetics, and an overall positive outcome. Conclusions: The success rates, maintenance of marginal bone levels, and periodontal and aesthetic indices suggest the validity of implant-prosthetic rehabilitations with CAD/CAM abutments in cases of single crowns. Schlagwörter: Implant-prosthetic rehabilitation; CAD/CAM abutments; Single crowns; Clinical performance; Peri-implant soft tissues

Statement of Problem: Data on the clinical performance of monolithic Zirconia screw-retained crowns on external hexagon implants fabricated from digital scans through a cast-free, fully digital workflow is lacking and needs to be included. Purpose: This retrospective multicentric study aimed to evaluate the real-life clinical results of monolithic Zirconia screw-retained crowns without the interposition of a Ti-base on external hexagon implants fabricated from intraoral scans and a cast-free approach in private practices. Materials and Methods: Single external hex implant fixtures were restored with monolithic zirconia crowns without the interposition of a Tibase. The crowns were directly screwed on external hexagonal implant connections with a castfree, fully digital workflow. Data were analyzed using descriptive statistics and the Kaplan– Meier test. Between September 2022 and March 2023, the California Dental Association modified criteria were adopted for clinical evaluation after recalling all patients. Results: A total of 304 single tooth restorations in the maxillary and mandibular posterior regions fabricated between July 2014 and July 2022 in 252 patients (120 males and 132 females, mean age 53.6 years, SD 23.3). Seven crowns were excluded because of patient dropout. The most common minor technical complications were screw loosening (3 crowns) and loss of the screw-access hole filling (3 crowns). Four failures included two implant failures with mobility and two fractured crowns. No screw or implant fractures were recorded. The overall cumulative survival rate was 98.6% and the average success rate (crowns experiencing no failures or complications) was 96.0%. The mean overall survival time was 101.3 months (standard error, 0.847; 95% confidence interval for the mean, 99.67-102.99). The overall survival probability was 87.9% up to 97 months. Conclusions: With careful case selection and comprehensive periodontal maintenance program, single crowns directly screwed onto an external hexagon platform have shown to have excellent survival and success (complication-free) rates, comparable to available data regarding single crowns with a metal implant- prosthetic interface.

Purpose: The formation of a biological seal between implant abutments and the surrounding soft tissue is a preventive strategy against peri-implantitis. The aim of this study is to test the hypothesis that surfaces of prosthetic implant abutments treated with vacuum ultraviolet (VUV) light enhance the growth and function of human gingival fibroblasts. Materials and methods: Implant abutments were treated with 172 nm VUV light for one minute. Untreated abutments were subjected as controls. Their surface properties were characterized using SEM, contact angle measurements, and chemical composition analysis. Human gingival fibroblasts were cultured on both untreated and VUV-treated abutments to evaluate cell attachment, proliferation, distribution, and collagen production. Cell detachment assays were also performed under various mechanical and chemical stimuli. Results: After VUV treatment, implant abutments demonstrated a notable transition from hydrophobic to hydrophilic wettability. Surface element analysis revealed a considerable reduction in surface carbon and increases in oxygen and titanium elements on the VUV-treated surfaces. On day 1 of culture, 3.9 times more fibroblasts attached on VUV-treated abutments than on untreated control abutments. Fibroblastic proliferation increased 1.9-3.1 times on VUV-treated abutments, along with a significant improvement in the distribution of populating cells. Collagen production on VUV-treated abutments increased by 1.5-1.7 times. While untreated abutment surfaces showed voids and limited spread of collagen deposition, dense and full coverage of collagen was observed on VUV-treated abutments, with a great contrast in the challenging axial surface zone. Cell retention against mechanical and chemical detaching stimuli was increased 11.3 and 4.3 times, respectively, by VUV treatment. Conclusion: Treatment of implant abutments with VUV light for one minute resulted in a reduction of surface carbon and a transformation of the surface from hydrophobic to hydrophilic. This led to enhanced attachment, proliferation, and retention of human gingival fibroblasts, along with nearly complete collagen coverage on implant abutments. These in vitro results indicate the promising potential of utilizing VUV photofunctionalized implant abutments to enhance soft tissue reaction and sealing mechanisms. Schlagwörter: ultraviolet light; implant abutment; gingival fibroblasts; soft tissue attachment; photofunctionalization

Purpose: To explore the contribution of paired-related homeobox 1-positive cells to the implant-induced osseointegration process in adult alveolar bone and the potential underlying mechanisms. Materials and Methods: Cre recombinase-induced lineage tracing and cell ablation were conducted in a murine dental implant model. Scratch and transwell assays were used to assess MC3T3-E1 cell migration after paired-related homeobox 1 overexpression. Single-cell RNA sequencing were applied to identify potential genes involved in pairedrelated homeobox 1-positive cells-driven osteogenesis. Results: Paired-related homeobox 1- positive cells were observed to accumulate in the peri-implant area in a time-dependent manner. The number of these cells were found to reach its maximum on day 14. Osseointegration in mice were noticeably impaired after ablation of paired-related homeobox 1-positive cells. Further, it was discovered that paired-related homeobox 1 promotes MC3T3- E1 cell migration, a process which is indispensable for sound healing of peri-implant tissue.  Finally, Semaphorin 3C was detected exclusively and abundantly expressed by paired-related homeobox 1-positive cells. Knockdown of semaphorin 3C in paired-related homeobox 1- positive cells significantly weakened their osteogenic potential. Conclusion: Our data suggest that paired-related homeobox 1-positive cells contribute to the osseointegration process under stress stimulation and semaphorin 3C may play a critical role in paired-related homeobox 1- positive cell-driven osteogenesis. Paired-related homeobox 1 could significantly promote MC3T3-E1 cell migration. Schlagwörter: paired-related homeobox 1-positive cells, osseointegration, alveolar bone, semaphorin 3C

Purpose: Determining the esthetic success of single-tooth implant restorations (STIR) requires an objective tool such as one devised by Belser et al., 2009 - pink esthetic scores and white esthetic scores (PES/WES). This study aimed to utilized PES/WES to establish threshold scores based on (1) detectability and (2) acceptability of a STIR by lay person perception, (3) to study the difference in the ability of laypeople and dentists in detecting the presence of STIR, and (4) to study the pink and white deficiencies in relation to the detectability of the presence of STIR. Materials and Methods: A total of 38 calibrated photographs of STIR in the anterior region were scored with PES/WES by 3 prosthodontists. Next, 100 laypeople and 60 dentists were instructed to identify the STIR among the anterior teeth and provide reasoning behind the identification (based on pink and white esthetic criteria). The acceptance of the STIR was recorded. Receiver Operating Characteristics (ROC) analysis was utilized to determine the threshold scores. Results: At the PES/WES score of 17, 71% of laypeople could not correctly identify the STIR, and at the  PES/WES score of 12, 80% of laypeople accepted the implant. Out of 3,800 occasions, laypeople correctly identified the STIR 1,770 (46.58%) of those occasions. Among the correctly identified STIR, 751 (42.43%) of those occasions were identified with pink deficiencies and 1019 (57.57%) of those occasions were with white deficiencies. Out of 2,280 occasions, dentists correctly identified STIR 1869 (81.98%) of those occasions. Conclusions: The PES/WES score of 12 indicates the clinically acceptable threshold, while the score of 17 indicates the detectable threshold for an exceptional esthetic outcome. Laypeople tend to accept the implant despite its detectability. For both laypeople and dentists, root convexity/soft tissue color and texture are the most focused criteria of PES/WES, followed by overall white deficiencies that remain influential. Compared to laypeople, dentists tend to have a higher ability to detect STIR. Schlagwörter: pink esthetic scores, white esthetic scores, single-tooth implant restorations, implant esthetic

Purpose: This study aimed to identify the technical complications associated with maxillary complete-arch implant-supported fixed prostheses (ISFPs) and to evaluate the survival rates of both implants and prostheses. Additionally, we sought to analyze the impact of the presence of cantilevers, the type of prosthetic abutment, and the number of implants on the occurrence of complications. Materials and Methods: Data were obtained from standardized clinical assessments carried out in a single appointment by two calibrated professionals using information from dental records. Results: The sample consisted of 64 patients rehabilitated with ISFPs classified as hybrid prostheses (metal-resin). The survival rate for implants was 98.6% after 1 to 12 years (5.2 years ± 36.6 months) and was 100% for the prostheses after a follow-up  period of 12 to 144 months (mean 48.1 ± 33.94 months). The most frequent complications were occlusal wear (82.8% of patients) and loosening of prosthetic screws (16.6%) and abutments (8.1%). Screw loosening frequency was significantly greater in 30-degree abutments compared with straight abutments (P=0.008), but no significant difference was found between 17-degree and 30-degree abutments. Prostheses with a higher occurrence of screw loosening had a greater average CL/AP spread ratios (0.9 􀀀 0.5). In addition, abutments installed on distal implants were more likely to loosen (P<0.001). The absence of mutually protected occlusion did not significantly influence the loosening of screws and prosthetic abutments. Conclusions: Implantsupported fixed maxillary complete-arch rehabilitations have high survival rates but are subject to technical complications. Schlagwörter: dental implants, maxillary edentulism, mechanical outcomes, screw loosening, follow-up

Purpose: The aim of the present animal study was to examine the impact of two implant designs that promote different insertion torque values on implant stability and evaluate, histomorphometrically, the bone healing for immediate implant placement in fresh sockets. Materials and Methods: Twelve female sheep (35.0±5.0kg) and 48 conical Morse-taper dental implants divided into two groups (n = 24 per group): G1 group, where the implants present a design that can provide high insertion torque values; and G2 group, where the implants present a design that can provide low insertion torque values. Both had the same surface treatment, and dimensions (4.0 mm in diameter and 10 mm in length). The first two posterior teeth (both sides) were extracted carefully. Sequentially, there were osteotomies in the mesial socket of each molar tooth. The final implant position was 2 mm below the buccal bone crest level. On the right side, implants of the G1 were placed anteriorly, followed by implants of the G2; and, on the left side, it was the reverse. A digital torquemeter was used to measure the maximum final insertion torque value (f-IT). The initial implant stability quotient (ISQ) was measured immediately after the implant insertion (T0) and immediately after the euthanasia and removing the mandibles with the implants. The animals were euthanized (n=6 animals/ time) at 21 days (T1) and 35 days (T2). The t-test was used to compare statistical differences for each intragroup parameter analyzed. Pearson's correlation was used to analyze possible correlations: f-IT and BIC%, f-IT and ISQ, and ISQ and %BIC. Results: Regarding the insertion torque, the G1 presented higher values than the G2, with a statistically significant difference (p<0.0001). The ISQ mean values were higher in the B-L direction than those obtained for M-D for both groups. %BIC measurements showed higher values in samples from G2 than G1 at both times and in both directions. New bone, medullary spaces, and collagen matrix had statistical differences between the groups at each evaluation time. Conclusion: Using implants with a modified macrogeometry plays a significant role in implant stability and the healing process of bone tissue around the implant. It is important for clinicians to carefully consider implant macrogeometry when planning dental implant surgery to achieve optimal implant stability and successful osseointegration, mainly in cases of immediate implant placement. Schlagwörter: dental implants, macrogeometry, pre-clinical study, histomorphometry.

Purpose: To evaluate the feasibility of reversing a primary failure through therapeutic mechanical stimulation induced by transcutaneous application of acoustic waves (ESWT) in the peri-implant tissues. Materials and Μethods: This clinical report evaluates the outcome of a new protocol proposed to treat a primary failure (loosened oral implant); application of three cycles of ESWT, once session per week for 3 consecutive weeks, with an equivalent positive energy of 0,18 mJ/mm² (therapeutic dose: 2000 impulses/ 8Hz/ 4.0 bar). Standardized intraoral radiographs, Cone Beam Computed Tomography (CBCT), Implant Stability Quotient (ISQ) and clinical evaluations were performed. Results: It was possible to verify a progressive increase in the ISQ value after the ESWT protocol; 17 (initial), 46 (after two months) and 68 (after four months), which led to successful implant prosthetic rehabilitation (35 N/cm measured). Our evaluation at 6 years of follow-up confirms that the new bone-implant interface is preserved and ESWT as a safe non-invasive treatment. Conclusion: In the context of the new dynamic model of osseointegration, the Foreign Body Equilibrium (FBE), this represents the first report of a host-Implant equilibrium re-established after an early failure process. However, it is necessary to perform studies to determine both the medical device and the most effective therapeutic range for clinical applications of this technology in oral implantology.  Schlagwörter: ESWT, primary failure, case report, osseointegration, oral implant, osteoimmunology

Purpose: The purpose of this study was to examine the mechanical influence of edentulous mandibular morphology on peri-implant bone in implant prosthetics by finite element analysis. Materials and Methods: Computed tomographic data from 25 patients with edentulous mandibles were selected and the radius of mandibular curvature and the height of the mandible at the midline were measured in order to clarify the morphological characteristics of the mandible. From the measurement, two patients with the smallest and largest radii of the mandible were selected. Two types of three-dimensional finite element models consisting of the edentulous mandible (small and large radius), superstructure (a cantilever bridge), implants, and abutments were created. Four implants were inserted between the right and left mental foramina. The upper surface of the mandibular condyle was constrained, and a vertical load of 100 N was applied on the occlusal surface of the right first molar. Three-dimensional finite element analysis of each model was performed to examine the mechanical influence of the edentulous mandibular morphology on the peri-implant bone. Results: Measurement of mandibular morphology in CT images indicated that the lower the mandibular height was, the larger was the radius of the anterior mandibular curvature. Finite element analysis revealed that a higher equivalent stress was generated in the peri-implant bone of the model with a larger radius of curvature than that of the model with a smaller radius of curvature. The highest equivalent stress in the mandible was generated in the distal margin of the peri-implant bone posterior to the loaded side of the large radius of curvature model. Conclusions: The mandibular morphology had a mechanical influence on the peri-implant bone.

Purpose: Maxillary sinus floor augmentation is a safe and predictable technique used to increase bone volume under sinus cavity for implant placement in atrophic posterior maxilla before implant placement. Despite conflicting results concerning the new bone formation rates with or without a barrier membrane, the benefits of using a collagen membrane to cover the lateral bone window has been demonstrated, in order to prevent bone substitute particles dislodgement that may occur from the sinus cavity through the sinus antrostomy towards the oral mucosa, and to significantly reduce the postoperative swelling and pain reactions. The purpose of this case series is to present a sling suture technique used to stabilize the collagen membrane against the lateral bone window so as to improve the bone substitute stability inside the sinus cavity. Materials and Methods: Maxillary sinus floor augmentation with lateral approach using sling suture technique to maintain the collagen membrane against the lateral bone window was performed in 17 patients (8 women/ 9 men, mean age: 58.2 years). Postoperative cone-beam computed tomography (CBCT) images up to 6-month follow-up were performed to control the bone graft stability at the level of the lateral antrostomy. The clinical postoperative pain and swelling were assessed through a Visual Analogue Scale (VAS) questionnaire from level 1 (low), level 5 (acceptable), to level 10 (high) at one week postoperative. Results: No bone substitute displacement was observed for all clinical cases on the CBCT images at 6-month postoperative. The pain and swelling level observed at one-week post operative were significantly low (respectively 1.6±1.0/2.1± 0.9). Conclusions: Within the limits of this case series, the use of sling suture technique to maintain the barrier membrane at the level of the lateral bone window in case of maxillary sinus floor augmentation with lateral approach surgery revealed to be a predictable protocol to prevent bone substitute displacement outside the sinus cavity.

Purpose: This in-vitro study aims to investigate whether the wettability of two zirconia implant disk surfaces is affected by glycine and erythritol air-polishing, using saline, bovine serum albumin, bovine thrombin, and bovine artificial blood as the testing mediums. Materials and Methods: Zirconia disks were provided by two implant companies: SDS. (Swiss Dental Solutions, Plymouth, MA, USA) (n=6) and Patent. (Zircon Medical AG, Altendorf, Switzerland) (n=6). Surface parameters (Sa, Sz, Sdr, Ssk, Sku, and Spd) were measured to determine their initial surface roughness. Air-polishing was completed using glycine or erythritol powders using the AIRFLOW. PERIO device (Manufactured by Electro Medical Systems (EMS)). The wettability of the disk surfaces was evaluated by the contact angle analysis applied on treated and untreated disks using four wetting solutions, saline, bovine serum albumin (BSA), bovine thrombin, and bovine artificial blood. In total, 720 contact angle measurements were completed with n=30 per group. Statistical analysis was performed using the one-way analysis of variance and post-hoc Tukey HSD test. Results: The results indicate SDS. has a greater wettability than Patent. before and after air-polishing. The wettability of surfaces treated with glycine was hydrophobic in some cases. Erythritol increased the surface wettability of zirconia disks compared to glycine. BSA and bovine artificial blood had lower contact angles than saline and bovine thrombin for both untreated disks. Conclusions: The initial wettability of zirconia disks differs between manufacturers, and air-polishing with erythritol powder increases the wettability of zirconia implant disks for saline, bovine serum, bovine thrombin, and bovine artificial blood. Schlagwörter: contact angle, erythritol, glycine, wettability, zirconia

Purpose: To investigate the effect of lateral sinus floor elevation (LSFE) on sinus membrane (SM) thickness and sinus health in mucosa thickness less and more than 5 mm. Materials and Methods: LSFE was performed in a prospective controlled clinical trial on two groups with less than and more than 5 mm (group A & B) SM thickness and followed for 6 months. Using preoperative and 6-month postoperative CBCT and clinical evaluation, SM thickness changes (primary outcome variable), sinus health, augmented bone height, and length (augmentation adequacy), membrane–related variables, and operation time were measured. Results: Forty unilateral sinus augmentations (A:20, B:20) with simultaneous installation of 52 fixtures were performed on 40 subjects (72.5% males, mean age of 48.8±7.6). The mean preoperative and 6- month SM thicknesses in group A and group B were 1.4±0.9 and 1.3±0.6 mm, and 6.8±1.0 and 3.4±1.7 mm, respectively. The mean postoperative SM thickness significantly decreased (P<0.001) only in group B. The mean SM thickness changes also revealed a noticeable difference between the two groups (P<0.001). Augmentation adequacy and membrane perforation rate were similar in both groups. Clinical and radiographic rhinosinusitis was not detected in any of the patients. Bleeding during separation and resistance to elevation in group B were significantly higher than in group A (P=0.003, P=0.001). Surgical time in group B (12.08 ± 8.26 minutes) was longer than in group A (8.64 ± 3.70 minutes), without reaching a significant level (P=0.097). Conclusions: LSFE in thickened mucosa (≤10 mm) and thinner mucosa (≤5 mm) does not cause abnormal changes in the sinus membrane and sinus health. LSFE in thickened mucosa results in adequate sinus augmentation. Thickened SM also shows a significant thickness reduction. The thickened membrane does not appear to be a contraindication to SFE. Schlagwörter: Sinus floor elevation, Schneiderian membrane, sinus membrane, mucosal thickness, ostium patency

Purpose: To examine the stresses caused by different All-on-4 surgical techniques—conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation—on the implant and the surrounding bone using 3D finite element analysis (FEA). Materials and Methods: A 3D bone model of the  atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. Results: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. Conclusions: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications. 

Purpose: To assess the peri-implant and flap parameters of the prefabricated microvascular fibula flap and determine the dental implant survival rate. Materials and Methods: This retrospective study investigated a cohort of subjects who received prefabricated microvascular fibula flaps at two highly specialized tumor reconstruction centers. The subjects had all suffered atrophy or a large segmental defect of the jaws due to tumor resection or injury. Two independent surgeons determined the dental implant survival rate and assessed the peri-implant parameters and flap parameters during clinical follow-up. Results: In total, 41 subjects were treated with a prefabricated fibula flap between 1999 and 2012. Of these, 17 subjects (10 male, 7 female) with a total of 62 dental implants were examined. The other 24 subjects were unavailable for assessment and had to be excluded. Ten of the 62 dental implants (16.1%) had to be removed due to peri-implantitis before the follow-up assessment. Follow-up assessments were performed at intervals ranging from 2 to 12 years (mean: 7.2 years) after fibula flap transplantation. The dental implant survival rate was found to be 83.9%. A total of 208 dental surfaces were assessed. Overall, 96% of all surfaces had a pocket depth (PD) of ≤ 4 mm and 4% had a pocket depth of > 5 mm. An attachment level (AL) of 3 mm was measured in 48.5% of implants and ≥ 5 mm was measured in 15.9% of implants. Dental implants with a PD > 4 mm showed a significantly higher plaque index (PI) (75%; P = .0057), papillary bleeding index (PBI) (62.5%; P = .0094), and radiologic bone loss (P = .0014) compared to dental implants with a PD ≤ 4 mm. Conclusions: Reconstructive surgery using microvascular fibula flaps represents an alternative tool for oral rehabilitation in subjects suffering from a large segmental defect in the maxillary or mandibular bone compared to the conventional method. However, it appears that the different ossification processes that develop the fibula and the jawbones affect dental implant survival. 

Purpose: To compare the standard 360-degree CBCT acquisition protocol to the low dose 180-degree CBCT protocol for implant planning. Materials and methods: Two groups of patients, each consisting of 35 patients, were included in the study. The first group was imaged with the conventional 360-degree CBCT protocol, and the second group was imaged with the low dose 180-degree CBCT protocol. The primary outcome of this study was the number of scans that needed to be repeated due to poor image quality. In addition, six secondary parameters were evaluated quantitatively and qualitatively. Results: The results showed that there was no need to repeat any of the CBCT scans that were obtained in either group, which showed that 360-degree and 180-degree protocols had comparable image quality. As for the secondary parameters, the results showed that the evaluators were able to evaluate the six chosen parameters in a comparable manner. Conclusion: The 180-degree low dose CBCT scan is a viable option for dental implant treatment planning in the posterior mandible as it provides comparable and adequate information regarding accuracy of measurements, identification of critical structures, evaluation of bone quality, and any pathology. Schlagwörter: CBCT, implant planning, 180-degree, dental implant, ALARA, radiation, low-dose radiation, radiology

Purpose: To examine the changes of dentoalveolar structures and pathologies in the maxillary sinus before and after dental implant surgery alone or with direct vs indirect sinus lifting using CBCT images of the maxillary posterior region. Materials and Methods: Preoperative and postoperative CBCT images of 50 sinus sites and the alveolar bone around 83 implants in 28 patients were evaluated. Maxillary sinus pathologies were classified as mucosal thickening (MT), mucus retention cyst (MRC), polyp, and sinusitis before and after surgery. The changes after surgery were determined to be no change, reduction in pathology, or increase in pathology. Comparisons of pathology changes among the treatment groups were evaluated statistically with chi-square test, McNemar test, and Mann-Whitney U test. Results: Of the 50 sinuses evaluated for the presence of sinus pathology, 24 of 50 did not change postoperatively, the pathology increased in 10 sinuses, and the pathology decreased in 16. When the maxillary sinus regions were evaluated after indirect sinus lifting, direct sinus lifting, and in patients who had only implant surgery, there was no statistically significant difference between pathology distribution in terms of the procedure applied to the sinus (P > .05). However, in the maxillary sinuses with a pathology before implant placement were evaluated postoperatively, a statistically significant difference was found in favor of the presence of a change in pathology (ie, improvement or a decrease; P < .05). The maxillary sinuses without pathology before implant placement showed a statistically significant difference for no change; ie, continuation of the healthy state (P < .05). Conclusion: This study showed that surgical procedures could have a direct effect on the sinus membrane and maxillary sinus. Both the implant procedure and surgical approach may have an effect on maxillary sinus pathology, as well as an increase or decrease of the pathology. Hence, further studies with a longer-term follow-up should be performed to better understand the correlation between implant surgery and pathology.