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

Purpose: This study compared three-dimensional (3D) accuracy of conventional and digital workflows in the fabrication of implant FAFDP frameworks for an edentulous mandible. Materials and Methods: A heat-polymerized polymethyl-methacrylate master model simulated an edentulous mandible to be restored with a fixed prosthesis supported by five implants (A-E). A conventional open-tray, splinted-coping polyether impression was poured with Type IV dental stone to produce a stone model, which was scanned with a dental laboratory scanner to produce a virtual model. Full-contour (ZFC, n=5) and cutback (ZCB, n=5) zirconia frameworks were fabricated with CAD/CAM. The stone model was used as a working model to fabricate conventional noble metal frameworks (CNB, n=5). Each test  framework was attached to five implants with 35Ncm torque application. Test models were fabricated with Type IV dental stone and allowed to set completely before removing the test frameworks. Centroid positions and central axes of the implants in master and test models were measured with a coordinate measuring machine and compared. The local coordinate system comprised of implant A centroid as origin; implants A, C, E as XY-plane; implants A, E as X-axis. Four linear distortion parameters (dx, dy, dz, dR), two angular distortion parameters (dθx, dθy), and 3D distance distortion values (ΔR, %ΔR) were assessed. Results: Magnitude of mean dx, dy, dz, and dR ranged from 39.9±26.4μm (CNB-B) to 263.3±94.6μm (CNB-E), from 56.9±5.4μm (ZFC-B) to 124.5±37.6μm (ZCB-C), from -8.3±27.6μm (ZFCD) to -24.6±17.3μm (ZCB-D), and from 80.6±29.4μm (CNB-B) to 263.3±94.6μm (CNB-E) respectively. Magnitude of mean dθx and dθy ranged from 0.025±0.486 degree (ZFC-C) to 1.490±0.383 degree (CNB-C), and from -0.050±0.171 degree (ZCB-B) to 1.263±0.501 degree (ZFC-C) respectively. One-way ANOVA found differences among groups for dx, dy, dz, dθx, and dθy at some implants, but there was no clear pattern on the poorest group. For global linear distortion, CNB-D fared the worst. CNB exhibited the worst accuracy in ΔR and %ΔR for all reference distances except A-E. Conclusions: There were no differences between ZFC and ZCB for all parameters. CNB fared poorest for ΔR and %ΔR for three of four reference distances, and for dR for one of four implant positions. Keywords: 3D accuracy, CAD/CAM, CMM, Implant prosthodontics

Purpose: Regenerative hard or soft tissue augmentation procedures (ReP) are crucial in dental implant therapy. This study evaluates the frequency, timing, and financial implication of these procedures before and after implant placement, alongside the influence of systemic conditions on the need for additional interventions. Materials and Methods: This cohort included patients who received implants with or without ReP at the University of Michigan Graduate School of Dentistry from 2011-2023. Data on demographics and systemic health conditions were collected and analyzed using univariable and multivariable logistic regression. Results: 4,803 patients (10,247 implants) were included—48.9% of the patients and 21.7% of the implants received at least one ReP. Ancillary ReP was needed for 14.7% of the implants. The most common of these was alveolar ridge augmentation (ARA) simultaneous with implant placement (42.1%) and alveolar ridge preservation (ARP) (26.4). Diabetics showed significantly higher odds of repeating procedures pre-implant (OR=5.47; p=0.016) and required more frequent hard tissue augmentations post-implant (OR=3.58; p=0.006). Cost analysis revealed that ReP constituted 12.9% of the total implant procedure cost. Notably, the mandibular anterior area was the most likely to undergo ReP (OR=2.08; p=0.001). Conclusions: One of every two patients received a ReP. Almost half of these patients received ARA (simultaneous or staged), and 1/4 received ARP. Diabetic patients exhibited significantly higher odds of requiring hard tissue augmentation pre-IP and post-IP. Trends showed a shift towards soft tissue augmentation over hard tissue procedures for managing peri-implant deficiencies. Keywords: Dental Implants; Regeneration; Alveolar Ridge Augmentation; Costs and Cost Analysis; Prevalence

Purpose: To investigate the effect of basis images’ number (BI) and metal artifact reduction (MAR) on artifact’s expression and trabecular bone architecture assessment in a medullary bone area close to a zirconium implant placed in different mandibular regions on CBCT. Materials and Methods: CBCT volumes were acquired using the Picasso Trio unit with a zirconium implant placed individually in either the anterior or posterior mandibular region, both with and without MAR, under two scanning modes: normal (450 BI) and high (720 BI). To measure the standard deviation (SD) of gray values, a region of interest was placed mesial to the zirconium implant fixture area for artifact’s assessment. For trabecular bone architecture analysis, a volume of interest was established in the same area. The fractal dimension (FD), connectivity density (Conn. Dn.), trabecular thickness (Tb. Th.), and trabecular spacing were calculated. Results: The zirconium implant fixture increased the SD of gray values, especially in the posterior region without MAR, while activating MAR reduced these values regardless of the scanning mode (P < .05). The number of BI generally had no impact on SD (P > .05), except in the posterior region without MAR, where the normal scanning mode showed higher SD (P < .05). Implant presence reduced FD and Conn. Dens. in the posterior region, although this effect was less pronounced with MAR enabled (P < .05). In the control group, overall, high scanning mode reduced FD and Conn. Dens (P < .05), with minimal effect on Tb. Th. and Tb. Sp (P > .05). Conclusions: The zirconium implant fixture increased artifact expression, particularly in the posterior mandibular region without MAR, which also resulted in decreased FD and Conn. Dens. While increasing the number of basis images had little effect on the parameters, MAR minimized artifact expression and the reductions in FD and Conn. Dens. Values. Keywords: Artifacts, Trabecular bone, Cone-beam computed tomography; Dental implant; Zirconium

Objective: To report the implant survival rates, clinical, and radiographic outcomes following a duration of over five years in the function of 2 immediately placed implants supported by a short-span fixed partial denture (FPD) in the anterior mandible. Materials and Methods: 100 individuals with immediately placed 2 implants (n=200) to support a 4-unit FPD in the lateral incisor’s region of the mandible for long-term functional life with different loading protocols  were chosen for this research. The participants were divided into 3 groups according to loading protocol after implant placement. Plaque index (PI), bleeding on probing (BOP), probing depth (PD), radiographic crestal bone level (CBL) and implant survival rate were evaluated. Results: Three implants failed out of 200. Seven years was the average years that the implants were in function, and the overall survival rate was 98.5%. The mean PI was 24.86 in group I, 24.45 in group ΙΙ, and 24.77 in group ΙΙΙ. Group Λ had a mean BOP of 29.48, group ΙΙ had a mean BOP of 29.03, and group ΙΙΙ had a mean BOP of 29.12. For group Ι, the mean PD was 2.03; for group ΙΙ, it was 2.09; and for group ΙΙΙ, it was 2.11. For group Ι, the mean radiographic CBL was 1.69; for group ΙΙ, it was 1.56; and for group ΙΙΙ, it was 1.57. There was no significant difference among the 3 groups regarding PI, BOP, PD, CBL, and implant survival. Conclusions: Within the limitations of this retrospective study, immediate loading protocol of immediately placed dental implants in the mandibular lateral incisor’s region is a reliable dental rehabilitation choice and represents a valid alternative to the traditional delayed loading rehabilitation. Clinical significance: Immediate implant placement and immediate loading protocol can be advantageous for both patients and physicians. It can save costs and treatment times, and it might be a good alternative for patients who have high aesthetic standards for their anterior mandible. Keywords: Immediate implant placement, mandible, implant survival rate, loading protocols, short-span FPD

Purpose. The purpose of this study was to examine and compare the strain distribution around long and short implant mandibular overdentures retained either by ball or self-aligning stud (Positioner) attachments. Material and methods. Two completely edentulous mandibular models made of epoxy resin were used with implants placed equidistantly in the canine region. In the first model, two long implants were inserted, while two short implants were inserted in the second model. Two attachment mechanisms were examined for each model. A total of twentyfour identical mandibular overdentures were constructed and divided into two groups for each model (n = 12). Each model had two subgroups: ball attachments (n = 6) and Positioner attachments (n = 6). Two linear strain gauges were bonded to the epoxy at their corresponding prepared sites around each implant, where the microstrain was measured under bilateral and unilateral vertical loads of 100N. One-way ANOVA with post-hoc pairwise comparison and an independent t-test were used to analyze the microstrain value data (α =.05). Results. When comparing ball and Positioner attachments, the Positioner showed significantly higher microstrain than the ball attachment (P <0.001) for both bilateral and unilateral loading. When long and short implants were compared, no statistically significant difference was found in bilateral loading (P = 0.22) or unilateral loading (P = 0.19; P = 0.16) on both loading and nonloading sides. Conclusions. A higher strain distribution around implants was induced by the Positioner attachment compared to the ball attachment, regardless of the implant length. Increasing the implant length was not advantageous. Thus, the use of short implants for retaining mandibular overdentures can be a viable alternative treatment option. Keywords: short implants; implant-retained overdentures; resorbed ridges; peri-implant stress

Vertical ridge augmentation has less long-term predictability than horizontal ridge augmentation due to common complications with vertical Guided Bone Regeneration (GBR), including early exposure of the barrier membrane and decreased bone stability. Objective: The purpose of this study was to evaluate the primary stability of short implants versus conventional implants, in vitro. Methods: Two groups of implants with reverse concave neck and neck micro threads (ULT, Ditron Dental, CA) were studied; short implants (Ø 6.0mm x 7mm) and conventional implant (Ø 3.75mm x 10mm). A total of 80 implants were placed by the same calibrated clinician at 800RPM, 40 short implants and 40 conventional implants. Each implant was placed in dense (type II) and soft (type IV) bone. Implant primary stability was recorded using insertion torque (IT), Resonance Frequency Analysis (RFA), and Periotest values. Statistical comparison with Analysis of Variance were completed to compare differences between groups. Results: The comparison of IT, RFA and Periotest of the two groups of implants showed statistical significance (P<0.0001) favoring the short implants (Ø 6.0mm x 7mm) in both the soft and dense bone qualities. Conclusion: Within the limitations of this study, short implants with wide diameter seem to have a higher level of implant stability compared to narrow implants with conventional length. Keywords: implant stability; reverse concave neck; short implants

Purpose: This study aims to assess the differences between a leukocyte- and platelet-rich fibrin (L-PRF) and deproteinized bovine bone mineral block and a combination of 50% autogenous bone (AB) and 50% deproteinized bovine bone mineral (DBBM) as grafting material for horizontal guided bone regeneration (GBR). Materials and Methods: This randomized double-blind split-mouth clinical trial included 13 subjects requiring bilateral horizontal bone augmentation. Each patient received both treatment modalities: one side of the jaw was treated by GBR with the L-PRF and deproteinized bovine bone mineral block, and the other side with a 50/50 mixture of AB and DBBM. Cone beam computed tomography (CBCT) scans were used to evaluate horizontal bone width (HBW) and buccal bone thickness (BBT) at various time points: baseline (T0), immediately post-augmentation (T1), at implant placement (T2), and one year after abutment connection (T4). Bone sounding (BS) was also used to verify CBCT measurements. Results: No statistically significant differences were found in HBW gain between test (L-PRF) and control (AB/DBBM) sites at any timepoint. Both sites showed significant HBW loss post-implant placement, with more bone volume lost at higher crestal levels (Sh0 > Sh2 > Sh4). At the Sh2 level, 48.8% of the HBW gain at T1 was lost by T4 in test sites, and 46.2% in control sites. Similarly, BBT at Sh2 reduced from 4.7 ± 1.0 mm to 1.3 ± 1.5 mm in test sites and from 2.1 ± 1.0 mm to 0.9 ± 0.8 mm in control sites. Both groups of sites had one complication, resulting in a 91.6% success rate for both treatments. The cumulative survival rate of implants was 100% at 16 months, with a mean interproximal bone level (IBL) loss of 0.2 ± 0.9 mm and 0.1 ± 0.6 mm for test and control sites, respectively. Conclusions: No statistically significant differences were found between the AB/DBBM composite graft and the L-PRF and bovine bone mineral block for horizontal GBR. Significant resorption of grafted volume occurs within 25 months, continuing post-implant placement. Further research with larger sample sizes is needed to confirm these findings and optimize GBR techniques. Keywords: autogenous bone, guided bone regeneration, L-PRF bone-block, horizontal bone augmentation

The release of titanium nanoparticles during implant placement in dense bone is a significant concern, as it can potentially have adverse effects on the peri-implant tissues and an impact on the etiology of peri-implant diseases. The objective of this study was to examine the presence of titanium nanoparticles at the bone-implant interface during implant placement utilizing the bone condensation technique in vitro. Artificial Type IV bone slices (4mm thick) were securely held in place with a vice. Two groups of implants were placed. One group (test group) was placed under the condensation technique using cylindrical osteotomes. The other group (control group) was placed following the traditional surgical protocol. Implants were placed in parallel between bone slices held in a vice. Three groups of implant designs (6 implants in each group) were inserted into the bone. Two implant designs consisted of implants made of pure titanium (grade 4), while the third implant design group was constructed of titanium alloy (Ti6Al4V). Subsequently, the blocks were separated, and the peri-implant bone interface was qualitatively evaluated for titanium presence using X-ray-fluorescence spectrometry (XFS) at the coronal, middle, and apical thirds of osteotomies (n=12/ implant system). Descriptive statistical analysis showing the mean values (+/-SD) of titanium nanoparticles was performed. No detectable titanium levels were identified in the control group of titanium alloy-implants compared to pure titanium-implants. In contrast, the test group of all implant systems showed presence of titanium nanoparticles in coronal, middle, and apical thirds. Our results indicate that bone condensation technique is associated with titanium release during implant placement in vitro. These findings were shown for both pure titanium- and titanium alloy-dental implants. Keywords: condensation, interface, primary stability, titanium nanoparticles

Purpose: The aim of this study was to compare heat generation during osteotomy for dental implant placement using conventional (sequential drilling) and single drill protocol in digitally guided surgery and to clarify differences in thermal exposure time. Materials and methods: In this study, we used a bovine rib ex vivo model with a surgical splint and a type K thermocouple to measure temperature and time. The conventional protocol (n=20) involved sequential drilling using 6 drills of increasing diameter, while the simplified protocol used a single drill (n=20). On the other hand, four implant beds were prepared in the tibia of a New Zealand rabbit to compare the mean temperature values between the in vivo and ex vivo models. Results: Student’s t-test revealed no significant differences (p=0.1688) in temperature elevation between the conventional drilling (mean, 1.977ºC; sd 1.165) and single drilling (mean, 2.634ºC; sd 1.734) protocols. However, significant differences between the groups were found in the exposure time: 107.105 seconds (sd 29.196) and 16.842 (sd 8.101) respectively. The mean temperature increase due to drilling was 0.365ºC (sd 0.204) and 0.378ºC (sd 0.381) in the rabbit tibia and bovine rib, respectively, with no significant differences (p-value = 0.926) between the in vivo and ex vivo models. Conclusions: Conventional and single drill guided surgery protocols for implant bed preparation generate similar temperatures in vitro. Exposure time is longer with conventional protocols than with single drill protocols. Keywords: drilling protocol, digitally guided surgery, osteotomy heat, exposure time, dental implant.

Purpose: This systematic review and meta-analysis aims to analyze the risk of prosthesis complications across different implant diameters. Materials and Methods: An electronic search across PubMed (MEDLINE), Embase, Scopus, and Cochrane Central Register of Controlled Trials until December 2023 was performed. Studies comparing implant prosthesis complications among extra-narrow (<3.0 mm), narrow (≥3.0 to <3.75 mm), standard (≥3.75 to <5 mm), and wide-diameter (≥5 mm) implants were included. Meta-analyses were performed to evaluate the risk ratio of prosthesis complications across different diameters, particularly in non-full arch implant-supported fixed dental prostheses (ISFDP). Results: Eighteen clinical studies were included. In non-full arch ISFDP, the most prevalent complication was screw loosening in narrow, standard, and wide-diameter implants (17.28%, 4.08% and 12.45%, respectively), and decementation (3.4%) in extra-narrow diameter implants. In implant overdentures, extra-narrow, narrow and standard-diameter implants demonstrated high rates of retentive cap wear (58.33%, 80.49% and 70%, respectively), whereas wide-diameter implants had 16.67% overdenture repair. The meta-analyses showed a risk ratio of 0.20 (95% confidence interval= 0.04 to 0.94, p= 0.04) and 0.17 (95% CI= 0.06 to 0.45, p< 0.0004) for abutment fracture in single crowns and ISFDP comparing narrow versus standard-diameter implants. No significant differences in risk ratios were observed for screw loosening, decementation, porcelain chipping, fracture, or screw fracture among the different diameter groups. Conclusions: This systematic review highlights that screw loosening and retentive cap wear are the most common prosthesis complications in ISFDP and overdentures, regardless of implant diameter. While narrow-diameter implants have a lower risk of abutment fracture compared to standard-diameter implants, clinicians should carefully consider patient characteristics, implant locations, and abutment features when selecting the ideal implant diameter. Keywords: Dental implants, narrow-diameter implants, screw fracture, screw loosening, abutment fracture, prosthesis complications

Purpose: Implant stability (IS) is crucial to the success of any implant-based therapy. The present work aimed to determine the relationship between primary and secondary stability and a range of variables. Material and Methods: This retrospective cohort study included a total of 169 patients, who received 445 dental implants. A case history for each participant was created. Data collection included each patient’s age, implant design, length and diameter, bone type, and surgical factors. Implant Stability Quotient (ISQ) values were measured at baseline (T0: primary stability) and T1 (secondary stability). To calculate the ISQ values at T0, T1 and their differences in the variables age, design, length and diameter, a multivariate ANOVA test was performed to determine which variables acted as confounding factors and to adjust the ISQ values to these variables. Results: The main variables age, design, length and diameter were adjusted to their confounding factors. Regarding primary (T0) and secondary (T1) stability, statistically significant differences (p<0.05) were only found in implant diameter, with the larger the diameter, the greater the stability. In all the other main variables, no statistically significant differences were found for primary and secondary stability. Conclusions: It may be concluded, within the limitations of the study, that the implant diameter variable is the one that significantly affects the primary and secondary stability of the implant. Keywords: Dental implant; Implant Stability Quotient; Resonance Frequency Analysis; Primary Stability; Secondary Stability, Patient age

Purpose: The available scientific evidence on the effectiveness of the surgical treatment of peri-implantitis is limited. The aim of this study was to assess the risk of recurrence or disease progression in patients with peri-implantitis that underwent surgical treatment. Materials and Methods: A retrospective cohort study was carried out in patients subjected to peri-implant surgery between 2015 and 2021, and with a minimum follow-up of 12 months. Data were analyzed using simple binary logistic regression models at patient level and generalized estimation equations at implant level. Results: A total of 34 patients and 103 implants were analyzed (70 undergoing resective techniques and 33 regenerative procedures). Fifteen patients (44.12%) experienced peri-implantitis recurrence and one patient (2.9%) lost one implant. No differences were found between the surgical techniques (p = 0.56). A history of periodontitis (ORa = 4.62; 95%CI: 1.14 to 18.75; p = 0.032), maxillary location (ORa = 9.69; 95%CI: 1.81 to 51.87; p = 0.008) and two implants treated per procedure (ORa = 31.68; 95%CI: 3.91 to 256.54; p = 0.001) were seen to increase the risk of recurrence. Conclusions: Almost half of all patients (44%) undergoing surgical treatment of periimplantitis will present disease progression or recurrence. This risk seems to be higher in patients with several treated implants, with a history of periodontal disease, or when the maxilla is involved. Keywords: Peri-implantitis; surgical treatment; dental implant.

Purpose. This retrospective clinical study aims to analyze single-unit implant-supported restorations' clinical and radiographic outcomes comprehensively. Materials And Methods. In this retrospective study, patients who had undergone 12 months of implant-supported singleunit fixed prosthetic treatment were scanned from the archives, and a hundred patients were included in the study. Implant success and survival rates were assessed according to the consensus decisions published at the International Oral Implantology Congress in 2007. Prosthetic complications such as chipping, screw loosening, and decementation were also evaluated. In addition, success/survival rates and prosthetic compositions were associated with some surgical and prosthetic parameters. Results. According to the success/survival criteria, 88% of the implants were successful, 10% had satisfactory survival, and 2% had compromised survival. The risk of satisfactory or compromised survival was 62.5 times higher in individuals with inadequately keratinized mucosa compared to those with adequately keratinized mucosa (p < 0.001). It was also 5.736 times greater for extractions due to periodontal disease versus endodontic reasons (p = 0.010) and 4.629 times higher for implants with diameters less than 3.75 mm compared to those between 3.75 mm and 5 mm (p = 0.037). Screw loosening was observed in 15% of the evaluated restorations, decementation in 13% and chipping in 4%, and the risk of screw loosening was 4.444 times higher for screw retention abutments compared to standard abutments (p=0.015). CONCLUSION. Insufficient keratinized mucosa, periodontal problems leading to tooth extractions, and the use of narrowdiameter implants can negatively affect the success of implant procedures. Loosening in screw-retained restorations is due solely to screw loosening, which is a high risk for screwretained restorations. Loosening in cement-retained restorations, on the other hand, is caused by the decementation of the prosthetic restoration or loosening of the abutment screw supporting the restoration. Keywords: peri-implantitis, prosthetic procedure, single implant

 Purpose – The use of the one abutment one time concept involves the indirect measurement of the implant stability without removing the previously placed abutment. This study aims to verify whether measuring the implant stability quotient at the abutment level is identical to the value obtained at the implant level. Material And Methods – A retrospective clinical study and an in vitro study were performed. For each study, the implant stability quotient measured at the implant level defined the control groups. The values obtained after the abutment seating composed the test groups, which were divided into three test sub-groups, corresponding to three different multi-unit abutments: straight (MUAS) and 17° angled (MUA17), both with 2.5 mm collar, and 30° angled (MUA30) with 3.5 mm collar. Data was compared by the Wilcoxon signed rank test and Kruskal-Wallis test. Results – Clinical results: the control group (59 implants; 79.14 [SD=3.39]) showed significantly higher measurements than the test group (73.22 [SD=8.54]); the sub-groups ClinicalMUA17 (16 abutments; 66.38 [SD=1.20]) and ClinicalMUA30 (16 abutments; 69.19 [SD=0.96]) measurements were lower than the control group. No differences were found for the ClinicalMUAS (27 abutments; 79.67 [SD=1.48]) sub-group when compared with the control group (correlation of 0.68). In vitro results: the control group measurements (36 implants; 68,02 [SD=1.81]) were significantly higher than the test group (62.57 [SD=2.87]). The control group measurements were also higher than each test sub-group (12 abutments each): MUAS (65.44 [SD=0.73]); MUA17 (60 [SD=0.43]); MUA30 (62.29 [SD = 0.35]). Conclusions: Based on the results of this study, determining the implant stability quotient at abutment level results in lower values than measurements at implant level, and may not accurately reflect the actual implant stability. Future research will need to explore whether, and under what circumstances a correlation exists between the implant stability quotient measured at the implant level and at the abutment level.

Purpose: This retrospective cohort study aimed to evaluate the survival rates and risk factors associated with Resorbable Blast Media (RBM) surface dental implants. The study involved 1,130 implants placed in 260 patients, with a follow-up ranging from a minimum of 26 months to a maximum of 120 months, for an average of 60 months. Materials and Methods: 1,130 RBM surface implants with hybrid macro-geometry were placed in 260 patients. Implant survival and failure rates were analyzed over an average 60-month follow-up. Failure rates were examined based on implant length, patient gender, and sinus lift procedures. Additional factors, including patient age, implant placement timing (immediate vs. delayed), guided bone regeneration (GBR), implant diameter, and implant location, were assessed to determine their impact on long-term implant success. Results: The overall survival rate for the implants was 94.4%, with most failures occurring within the first 12 months postplacement. Male patients experienced significantly higher failure rates (7.36%) than female patients (4.0%). Short implants (8 mm) were particularly vulnerable to failure, with an 8.65% failure rate. Sinus augmentation procedures also presented an increased risk, with 10% failure for lateral sinus augmentation and 9.78% for crestal sinus elevation. In contrast, factors such as patient age, timing of implant placement, GBR, implant diameter, and implant location did not significantly influence failure rates. Notably, narrow-diameter implants (3.3 and 3.7 mm; n=97) in the molar region did not increase the risk of failure, with only 5 experiencing failure. Failures post-prosthetic loading were most common after about 3 years. Conclusions: This study confirms the long-term viability of RBM surface implants, with high survival rates when early failures are mitigated. Short implants and sinus lift procedures pose greater risks of failure, particularly in the early stages. However, simultaneous GBR and sinus procedures did not significantly impact long-term outcomes, affirming the safety and efficacy of these complex interventions. Keywords: Failure analysis, Guided bone regeneration, Immediate loading, Immediate placement, Implant Survival, RBM Surface, Sinus lift

Introduction: Diabetes Mellitus (DM) poses a significant global health concern, with approximately one in two affected individuals remaining undiagnosed. The failure to diagnose or inadequately control DM can lead not only to systemic complications but also to decreased dental implant survival rates, increased marginal bone loss, and increased susceptibility to peri-implantitis. This study aims to evaluate glycated hemoglobin (HbA1c) levels in patients who have not been diagnosed with DM but exhibit oral DM symptoms prior to dental implant surgery. Materials and Methods: This study was designed as a retrospective cohort. It was conducted on patients who previously presented to the Department of Oral and Maxillofacial Surgery for dental implant surgery and had not been diagnosed with DM. The inclusion criteria included the need for dental implants and augmentation, presence of oral DM symptoms, and having blood tests that included HbA1c. Patients with a prior diagnosis of DM were excluded from the study. Results: A retrospective analysis was conducted on data from 253 patients who applied for dental implant surgery. Among them, 72 patients underwent HbA1c levels assessment through blood tests. Patients with previously uncontrolled DM (n:21) and those whose blood tests were performed at different institutions (n:8) were excluded from the study. Consequently, the study encompassed a cohort of 43 patients. Among the participants, 55% were female and 45% were male. The HbA1c values of the patients ranged from 5.1 to 10.9, with an average value of 6.57±1.44. Of the patients, 41.8% were diagnosed with DM, 30.2% were prediabetic (preDM), and 27.9% did not receive any diagnosis. There was no statistically significant relationship between the combinations of xerostomia, delayed wound healing, oral infection, burning sensation in the mouth, periodontitis, and dental caries with HbA1c levels (p>0.05). In this study, patients presenting to the clinic for dental implant surgery were directed based on oral symptom findings, and the rates of diagnosed DM and preDM were determined to be 7.11% and 5.14%, respectively. Conclusion: Considering the negative effects and prevalence of uncontrolled DM, it may be recommended to assess the HbA1c levels in patients with oral symptoms before dental implant surgery.

Purpose: This study evaluates the impact of metal artifacts in cone-beam computed tomography (CBCT) on the accuracy of static and dynamic computer-assisted implant surgery (CAIS) techniques. Materials and Methods: An implant was placed on each of thirty 3D-printed models embedded with Cobalt-Chrome strips to simulate metal artifacts by Porcelain-fused-to-metal (PFM), utilizing these CAIS techniques: radiographic template (RT) (n=10), radiographic markers (RM) (n=10), and dynamic navigation (DN) (n=10). Trueness and precision were analyzed by comparing 3D global deviation and the difference in implant positions at the neck, apex, depth, and angle in initial planned and final placed scans. Results: DN exhibited significantly lower 3D global trueness deviation to RT (p = 0.022) and lower angular deviation compared to both RT (p = 0.003) and RM (p = 0.002). RM showed greater trueness at the implant neck compared to DN (p = 0.005) and better depth trueness than RT (p = 0.001) and DN (p = 0.027). DN demonstrated higher precision in implant angulation than RM (p = 0.011) and RT (p = 0.041). Conclusion: In the presence of metal artifacts, both DN and RM techniques offered greater trueness in specific implant positions compared to RT. However, DN proved to be the most precise method for implant placement. Keywords: computer-assisted implant surgery; dynamic navigation; artifacts; 3-dimensional printing; accuracy

Purpose: Long-term data on the use of implants as surveyed crowns for implant-assisted removable partial dentures (IARPDSCs) are limited. This study evaluated the long-term outcomes and assessed the risk factors associated with marginal bone loss (MBL) in IARPDSCs. Materials and Methods: A total of 51 implants were placed in 14 partially or fully edentulous patients and restored using IARPDSCs. Implant crowns or bridges served as abutments for the removable partial dentures (RPDs) to enhance their esthetics, comfort, and function. All patients attended regular follow-up appointments every 3–6 months for up to 12.5 years; these visits included professional cleaning and oral hygiene reinforcement. The collected data included patient demographics, treatment modality, arch restoration, Kennedy classification, RPD connection and retention design, opposing dentition, implant characteristics (location, connection type, and diameter), and any complications. The clinical assessments included plaque score, bleeding on probing, probing depth, marginal tissue recession, and keratinized mucosa width. Univariate and multivariate analyses were performed to identify factors influencing the MBL of implants in IARPDSCs. Results: One implant failed during follow-up; thus, the implant survival rate was 98%. All patients were satisfied with their prostheses and reported only minor complications. Univariate analysis showed a significantly higher MBL in maxillary implants than in mandibular implants (P = .045). Multiple regression analysis revealed that bruxism (P = .002) and maxillary implants (P = .013) were significantly associated with a higher MBL. Female sex (P = .051) and anterior implants (P = .058) exhibited a trend toward an association with higher MBL. Conclusions: Within the limitations of this retrospective clinical study, IARPDSCs demonstrated predictable long-term success in carefully selected and well-maintained patients. Keywords: alveolar bone, dental implantation, mandible, maxilla, survival, removable partial denture

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. Keywords: dental implants, osseointegration, osteoporosis, osteoporosis treatment, bone, implant surface modifications

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. Keywords: dental implants, implant diameter, mixed model analysis, bone augmentation marginal bone level

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. Keywords: osteogenic differentiation, NF-E2-Related Factor 2, liposomal formulation, stem cells, regenerative dentistry

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. Keywords: zirconia crown, implant-supported fixed dental prosthesis, screw hole, occlusal thickness, axial thickness, fracture load

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.

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. Keywords: CO2 lasers; contact angle; irradiation; wettability

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. Keywords: Sinus lift; Bone substitute; Histomorphometric; Sticky bone; Schneider membrane perforation

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 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. Keywords: Analog design; angular deviation; implant analog; layer thickness; linear deviation

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. Keywords: immediate loading, implant-supported overdenture, edentulous mandible, telescopic denture, implant survival rate

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 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 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. Keywords: dental implants, finite element method, high-performance polymer PEEK, zirconia, lithium disilicate, hybrid ceramics

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.

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. Keywords: Immediate placement, prostheses, cohort study, tissue-level

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. Keywords: periodontal disease; staging and grading; risk factors; disease susceptibility; periimplantitis, risk assessment

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. Keywords: vertical guided bone regeneration, microCT, xenograft, d-PTFE, GBR

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. Keywords: Dental implant, osseointegration, lubricant, surface contamination

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. Keywords: Dental implants; Wettability; Osseointegration; Surface properties; Cell adhesion

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.  Keywords: Dental implant; implant fracture; implant diameter; Cantilever fixed bridge

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. Keywords: Tooth-implant; PEEK; FEA; Stress distribution; Static loading

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.  Keywords: extra narrow implants; fatigue; corrosion; saline solution, failure analysis.

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. Keywords: retrospective trial, titanium base, zirconia, two-piece hybrid abutment, implant-supported single crown.

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: 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. Keywords: Complete edentulouComputer-guided surgery, Immediate loading , Stackable guide, Full Arch rehabilitation, Autologous Bone graft.

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. Keywords: Dental implant, bone surgery, osteotomy, implant bur design, marginal bone resorption, success rate, quality of life.

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: 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. Keywords: Immediate implant; Magnesium citrate; Implant stability quotient; Analgesia; Osseointegration

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. Keywords: Biomechanical phenomena, fracture strength, Y-TZP ceramic.

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. Keywords: coral, graft, animal study, GBR, bone, rabbit.

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. Keywords: alveolar bone resorption, socket preservation, polylactide-co-glicolide acid, cone beam computer tomography

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. Keywords: ultraviolet light; implant abutment; gingival fibroblasts; soft tissue attachment; photofunctionalization

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. Keywords: 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.