The International Journal of Oral & Maxillofacial Implants, 05/2021

Purpose: Prosthetic rehabilitation of completely edentulous patients has been traditionally performed with complete dentures for many years. However, patient complaints are reported due to insufficient retention and high mobility of mandibular dentures. Therefore, in these patients, overdenture prostheses, which are usually made by placing at least two implants in the interforaminal region of the mandible, have become widespread. In these prostheses, bar, stud, magnetic, or ball and locator attachments are used. This study aimed to evaluate the stress on mandibles by an overdenture with locator attachments supported by two implants placed on three different bone types in three different regions. Materials and methods: Finite element analysis (3D) was used to design a mandible and overdenture. Two implants and locator attachment systems were placed into the lateral incisor, canine, and premolar regions. In computer-generated mandible and overdenture models, a force of 100 N was loaded obliquely and vertically from the mandibular first molar teeth region; then, the values obtained from the forces were compared. Eighteen analyses were performed with two different loading options in nine different models. Von Mises, compressive, and tensile stress values were analyzed. Results: As the bone type changed from D1 to D3, the stresses on the bone increased in direct proportion. However, with all three bone types, lower tensile values were found in cortical bone in an above-implant removable prosthesis supported by an implant in the lateral incisor region. Conclusion: Biomechanically, the lateral incisor and canine regions were more advantageous than the first premolar tooth region in prosthesis designs where two implants were used in all bone types. Keywords: 3D, finite element analysis, overdentures

Purpose: After some initial setbacks in the 1970s, ceramic implants seem to be a promising alternative to titanium implants. Since the surface of an implant system represents the interface to surrounding biologic structures, the study focuses on cleanliness and surface topography. Clinical documentation of the corresponding systems completes the picture and allows a better evaluation of zirconia implant systems. Materials and methods: Five different ceramic implant systems were selected randomly and purchased via blind-shopping: Z5s (Z-Systems), ZiBone (COHO), W implant (TAVDental), ceramic. implant (vitaclinical), and BioWin!/Standard Zirkon Implantat (Champions-Implants/ZV3 system). Three samples of each implant system underwent scanning electron microscopy (SEM) imaging and elemental analysis (EDS). Where appropriate, subsequent Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was performed to identify the chemical nature of impurities. Surface topography was evaluated, and a search for clinical trials in the PubMed database, on the websites and by written request to each dental implant manufacturer, was performed. Results: Surfaces of Champions implants (ZV3) and Z-Systems implants were relatively clean, whereas the other investigated surfaces of vitaclinical, TAV Dental, and ZiBone implants all displayed organic contaminations on their surfaces. Four of the investigated ceramic implants showed a moderately rough implant surface. Only the vitaclinical ceramic.implant had minimal surface roughness. Three ceramic designs-vitaclinical, ZV3, and Z-Systems-had clinical trials documented with up to 3 years of follow-up and results varying between 82.5% and 100% survival. TAV Dental W and ZiBone implant systems lacked properly conducted clinical recording of results. Conclusion: The results of this study showed that it is technically possible to produce zirconia implants that are largely residue-free. On the other hand, the variety of significant residues found in this analysis raises concerns, as contamination may lead to undesirable biologic effects. The lack of clinical studies in peer-reviewed journals does not seem to be relevant for the approval of marketing, nor does the lack of surface cleanliness. In the authors' opinion, a critical analysis of these aspects should be included in a more stringent future analysis prior to the marketing of oral implant systems. Keywords: ceramic implants, dental implants, implant contamination, implant surface, scanning electron microscopy, surface, surface properties, zirconia

Purpose: The aim of this systematic review was to evaluate the influence of zirconia and titanium as abutment materials on peri-implant soft tissue color. Materials and methods: The searched electronic databases included MEDLINE/PubMed, LILACS, Web of Science, Scopus, and LIVIVO. Two types of studies were included: randomized clinical trials (RCTs) and controlled clinical trials (CCTs) that compared zirconia (Zr) and titanium (Ti) abutments. The outcomes measured were as follows: implant crown esthetic index, visual analog scale, esthetic index, gingiva discoloration index-spectrophotometry, papilla index, recession index, and pink esthetic score. Two reviewers selected the records, assessed quality, and extracted data of included studies independently. Results: A total of 323 patients enrolled in 13 studies were included in this analysis with 11 RCTs and 2 CCTs. Due to the wide variety of methodologies used, meta-analysis was only possible for RCTs that performed spectrophotometric analysis. The use of zirconia or titanium for implant abutments does not seem to be the principal factor for influencing peri-implant soft tissue color. The meta-analysis showed no difference between zirconia and titanium abutments. Conclusion: This study does not support any better advantage of the use of zirconia in comparison to the use of titanium related to peri-implant tissue color. Keywords: abutment, color, systematic review, titanium, zirconia

Purpose: To investigate the influence of lateral window sinus augmentation on sinus physiology, including sinus membrane thickness and the outcome of antral pseudocysts. Materials and methods: This retrospective study was performed by reviewing all lateral window sinus augmentation procedures, which were done between the years 2013 and 2015. Each enrolled patient had CBCT images preoperatively (T0), immediately postoperatively (T1), and 6 months postoperatively (T2). The sinus membrane thickness, pseudocyst dimensions, and intraoperative perforation were evaluated. Patient-related factors such as age and sex that could influence the mucosal properties were also analyzed. Results: Based on established inclusion criteria, 306 patients with 320 sinuses were included in this study. The overall mean thickness of the sinus membrane (T0) was 1.30 ± 1.08 mm, and membrane thickening (> 2 mm) was observed in 22.19% of the sinuses. Preexisting pseudocysts were identified in 24 sinuses (7.50%), most of which remained unchanged or disappeared after 6 months. The intraoperative membrane perforation rate was lowest (1.96%) when the membrane thickness was 1.0 to 1.5 mm, and the perforation rate was increased in patients with thickened (> 2 mm) or thinned (≤ 1 mm) membrane. Membranes swelled immediately after operation (T1 vs T0, P < .01) and gradually recovered at 6 months. No significant change in membrane thickness was shown after the sinus augmentation procedure in the perforation group and pseudocyst group. The mean thickness of the sinus membrane at T0 and T1 was significantly higher for male subjects (P < .01). Conclusion: Lateral window sinus augmentation has little or no impact on sinus membrane thickness and antral pseudocysts after a 6-month healing period, except for a transient mild membrane swelling. Thickened and thinned membrane were risk factors for intraoperative perforation. Small-sized perforation and pseudocysts might not contraindicate sinus augmentation from the standpoint of the surgical impact on the sinus membrane. Keywords: antral pseudocyst, cone beam computed tomography, lateral window sinus augmentation, sinus membrane

Purpose: The purpose of this study was to compare changes in the physicochemical and biologic characteristics of titanium surfaces through short-term re-hydrophobization for 24 hours and ultraviolet (UV) re-irradiation for 24 hours. Materials and methods: Photofunctionalization was performed with four 15-W bactericidal lamps at an intensity of 5.0 mW/cm² (wavelength = 254 ± 20 nm) on sandblasted, large-grit, acid-etched (SLA)-treated titanium surfaces, which were stored in a sterilized sealed container for 8 weeks to allow enough biologic aging. The duration of the UV irradiation was as follows: irradiation group-UV irradiated for 24 hours; re-hydrophobization group-UV irradiated for 24 hours and then stored in an ambient sterilized medium; and re-irradiation group-UV irradiated for 24 hours followed by storing for 24 hours in an ambient sterilized medium and then UV re-irradiated for 24 hours. The surface characteristics were evaluated with field emission scanning electron microscopy, x-ray photoelectron spectroscopy (XPS), and water contact angle. Cell viability and morphology were measured using fluorescence staining. Alkaline phosphatase (ALP) assay and alizarin red S staining were performed to evaluate the differentiation of osteogenic cells and the mineralization capability. Results: Macroroughness and superimposed microroughness were observed on the disk surfaces in all groups as typically seen on SLA surfaces. The water contact angles were measured to be 1.85, 1.48, and 1.18 degrees for the irradiation group, re-hydrophobization group, and re-irradiation group, respectively, indicating superhydrophilicity. There was no difference in the surface elemental ratio or the spectra of XPS, cell viability, or ALP activity. Although the re-irradiation group had the highest total amount of calcium deposition, there was no statistical significance. Conclusion: Within the limitations of the study, improved superhydrophilicity and bioactivity after UV irradiation were maintained during short-term re-hydrophobization and repeated re-irradiation without changing the topography of SLA titanium surfaces. Keywords: biocompatibility, biologic aging, dental implants, osseointegration

Purpose: The aim of this study was to qualitatively and quantitatively assess the effect of osteotomy preparation by conventional, subtractive, or osseodensification instrumentation on osteotomies, treated with or without endosteal implants, and healing capacity. Materials and methods: Seven sheep were used, and 56 osteotomies were made in the left and right ilium of the sheep (n = 8/sheep [4 per side/time point (3 and 6 weeks)]). Two different instrumentation techniques were used: (1) conventional/regular drilling in a three-step series of a 2-mm pilot and 3.2-mm and 3.8-mm twist drills and (2) osseodensification drilling with a Densah Bur 2.0-mm pilot and 2.8-mm and 3.8-mm multi-fluted tapered burs. Drilling was performed at 1,100 rpm with saline irrigation. Results: Qualitative histomorphometric evaluation of the osteotomies after 3 and 6 weeks did not indicate any healing impairment due to the instrumentation. In all samples, histologic examination suggested bone remodeling and growth (empty and treated with an implant), irrespective of preparation technique. Osteotomies prepared using the osseodensification instrumentation showed the existence of bone chips autografted into the trabecular spaces along the length of the osteotomy wall. Conclusion: The osseodensification group yielded higher osseointegration rates, as distinguished through qualitative assessment, bone-to-implant contact, and bone-area-fraction occupancy, indicating an increased osteogenic potential in osteotomies prepared using the osseodensification technique. Keywords: histology, histomorphometric, oral and maxillofacial, osseodensification, periodontology, surgery, surgical procedure

Purpose: Despite the high success rate of implant-supported fixed restorations in dentistry, there is a lack of evidence on the marginal seal for dental cement. Thus, this study aimed to evaluate the marginal seal of implant-supported crowns and partial dentures cemented using four different dental cements. Materials and methods: The study evaluated the marginal seal of implant-supported crowns and partial dentures cemented using zinc phosphate, resin-modified glass-ionomer, self-adhesive resin, and noneugenol, acrylic-urethane polymer-based temporary dental cements. After cementation and thermal cycling procedures, the samples were incubated in Escherichia coli suspension for 5 days at 37°C under an aerobic environment. After debonding the restorations under sterile conditions, sterile cotton swabs were used to obtain microbial samples from the inner surface of each restoration and abutment surface. To analyze the contamination, each sample was immersed in a brain-heart infusion culture medium and incubated at 37°C for 24 hours, and then, the colony-forming units were counted and recorded. Results: Regarding the number of colonies for Escherichia coli, the results revealed no substantial difference between the crowns and the fixed partial restorations (P = .25). However, the differences in the level of contamination between the cement groups were significant (P ≤ .001). The self-adhesive resin cement samples showed the lowest level of contamination, followed by the zinc phosphate and resin-modified glass-ionomer cements. The difference in the level of contamination between these groups was not significant. The temporary cement group exhibited significantly higher numbers of bacterial colonies in comparison to the other cement groups. Conclusion: Self-adhesive resin cement has better biologic properties for retaining implant-supported restorations than other types of dental cement. Keywords: dental cement, dental implants, E coli, marginal leakage

Purpose: To develop and evaluate the accuracy of a computer-assisted system based on artificial intelligence for detecting and identifying dental implant brands using digital periapical radiographs. Materials and methods: A total of 1,800 digital periapical radiographs of dental implants from three distinct manufacturers (f1 = 600, f2 = 600, and f3 = 600) were split into training dataset (n = 1,440 [80%]) and testing dataset (n = 360 [20%]) groups. The images were evaluated by software developed by means of convolutional neural networks (CNN), with the aim of identifying the manufacturer of the dental implants contained in them. Accuracy, sensitivity, specificity, positive and negative predictive values, and the receiver operating characteristic (ROC) curve were calculated for detection and diagnostic performance of the CNN algorithm. Results: At the final epoch (25), system accuracy values of 99.78% were obtained for group training data, 99.36% for group testing data, and 85.29% for validation data. The latter value corresponded to the actual accuracy of carrying out the system learning process. Conclusion: This study demonstrated the effectiveness of CNN for identifying dental implant manufacturers, which was proven to be a precise method of great clinical significance. Keywords: artificial intelligence, deep learning, dental implants, radiology, supervised machine learning

Purpose: To evaluate the fracture resistance and failure mode of implant crowns made by polyether ether ketone (PEEK), zirconia, and chromium-cobalt frames, veneered by milled composite resin. Materials and methods: Thirty-six implant analogs were mounted in acrylic blocks, and solid abutments were secured (n = 12). Single-unit frameworks were milled from PEEK, zirconia, or chromium-cobalt, and cemented to indirect composite veneers fabricated by the rapid layering technique. After thermal cycling, the fracture resistance test was performed at a speed of 0.5 mm/min, and the results were statistically analyzed by one-way analysis of variance (ANOVA) and Tukey post hoc test (P < .05). The failure mode was evaluated by a stereomicroscope ('L10). Veneer failure without damage to other components was considered desirable (repairable). Results: The mean fracture resistances of PEEK, zirconia, and chromium-cobalt specimens were 2,037.24, 2,567.05, and 2,032.10 N, respectively. The Tukey post hoc test showed no significant difference between the PEEK and chromium-cobalt groups (P = .99); however, the difference was significant between zirconia and PEEK or chromium-cobalt specimens (P = .001). Failure mode was desirable in all chromium-cobalt (12 specimens), 9 zirconia, and 7 PEEK-based specimens. Conclusion: Zirconia-composite implant crowns had significantly higher fracture resistance. Given the range of maximum occlusal forces, all the specimens had clinically acceptable results. The failure mode was more desirable in chromium-cobalt, followed by zirconia-based crowns. Keywords: CAD/CAM, dental implant, failure mode, fracture resistance, polyether ether ketone

Purpose: The aim of this study was to compare the Streptococcus oralis biofilm formation on titanium machined turned surfaces and sandblasted surfaces that were previously characterized for their superficial topographies. Materials and methods: Two commercially pure titanium surfaces were analyzed and compared: machined (turned surfaces subjected to a process of decontamination that also included a double acid attack) and sandblasted (sandblasted surfaces, cleaned with purified water, enzymatic detergent, acetone, and alcohol). The characterization of the samples at the nanolevel was performed using atomic force microscopy, which permitted calculation of the superficial nanoroughness (Ra). The sessile drop method was used to measure the water contact angle in both groups and allowed information to be gained about their wetting properties. Scanning electron microscope and energy-dispersive x-ray spectroscopy analysis allowed comparison of the microtopographic geometry and the chemical composition of the samples. Then, the disks were pre-incubated with saliva in order to form an acquired pellicle. Streptococcus oralis was put on the disks, and both groups were tested at 24 and 48 hours for biofilm biomass evaluation, colony-forming units (CFUs), and live/dead staining for cell viability. Results: The sandblasted samples were characterized by a significantly higher level of superficial oxides, superficial roughness, and hydrophilicity, compared with the machined turned samples. Although there were topographic differences, the Streptococcus oralis biofilm formation, quantified in CFUs, and biomass formation at 24 and 48 hours were similar in both groups. With the live/dead staining, the sandblasted disks were characterized by an increased percentage of dead cells compared with the machined disks. Conclusion: Although significant topographic differences were present between machined and sandblasted disks, the Streptococcus oralis biofilm formation seems to not be significantly affected. Keywords: bacteria, biofilm, biomaterials, microbiology, nanosurfaces, titanium surface

Purpose: To evaluate the accuracy of available bone width, height, and length measurements on pre-planned implant sites using CBCT images scanned at different angulations of the mandible. Materials and methods: Standard cylindrical holes were prepared on six dry human mandibles and filled with warm gutta-percha to create spherical markers for measurements of available bone width, height, and length. Mandibles were first scanned with a CBCT device in an ideal position with the occlusal plane parallel to the horizontal plane. Then, images of the mandibles were obtained in rotation, tilt, flexion, and extension positions using 5- and 10-degree angulations. Measurements were done on a total of 54 images. Original dimensions of the available bone for planned implant sites were measured with a digital caliper on dry mandibles as the gold standard. The absolute values of the differences between each measurement and the gold standard were obtained for measurement errors. Repeated-measures analysis of variance and Dunnett's multiple comparisons test were used for comparisons (P = .05). Intraobserver and interobserver agreement was calculated using intraclass correlation coefficient (ICC). Results: ICC was excellent for both intraobserver and interobserver reproducibility. No significant difference was found between length and height measurements in ideal position and in rotation, tilt, flexion, and extension movements of mandibles at two different angulations (P > .05). Width measurements revealed a significant difference among ideal measurements and measurements at 10-degree flexion, 10-degree extension, 10-degree rotation, and 10-degree tilted mandibular positions (P < .05). Conclusion: The position of the occlusal plane with respect to the floor during the CBCT scan may have a clinically significant effect on dental implant site dimensions. Keywords: clinical assessment, CBCT, dental implant, imaging

Purpose: This clinical study was conducted to compare the influence of a platform-switched bone-level implant and a platform-matched tissue-level implant on marginal bone loss during the first year after loading. Materials and methods: Edentulous subjects who applied for two-implant-retained mandibular overdentures and showing sufficient bone volume for implants with 4.3-mm diameter and 12-mm length were enrolled. For standardization reasons, all subjects received a platform-matched tissue-level implant and a platform-switched bone-level implant in the anterior mandible. Since implants from the same manufacturer were used, both implants had identical implant thread designs and surface properties. All subjects received two-implant-retained mandibular overdentures with opposing maxillary complete dentures, and the implants were loaded after 6 weeks. Marginal bone loss was monitored via panoramic radiographs obtained immediately after loading and at the 6- and 12-month recalls after implant loading, and periodontal parameters, such as pocket probing depths, Plaque Index scores, and bleeding on probing, were also measured and recorded. Results: Twenty-six patients received 26 bone-level and 26 tissue-level implants. No statistically significant differences were detected between the bone loss of the two groups for all the measurements (P > .05). Additionally, no significant difference was detected between the measured periodontal parameters of the two groups (P > .05). Conclusion: Within the limitations of this prospective clinical study with a follow-up time of 12 months, it can be concluded that the platform-switching bone-level design and the platform-matching tissue-level design show similar bone loss in the anterior edentulous mandible. Keywords: biologic width, bone level, implant collar design, marginal bone loss, platform switching, tissue level

Purpose: The aim of this study was to determine a predictive decision model for peri-implant health and disease and to reveal the highest accuracy of prediction using three different data mining methods. Materials and methods: This cross-sectional study included a total of 216 patients with 542 dental implants from the Periodontology Department of Gazi University. The implants were classified into peri-implant health, peri-implant mucositis, and peri-implantitis groups based on established clinical and radiographic assessments. Prediction models were created using clinical variables in combination with possible risk factors for peri-implant diseases. Different data mining methods (decision-tree [DT]; J48), logistic regression, and artificial neural network (multilayer perceptron [MLP]) were compared to yield a better predictive decision model based on predictor variables with the highest potential of effect. Results: The prevalence of peri-implant mucositis and peri-implantitis among the participants of the specialist referral periodontal practice of the university was 36.1% (95% CI: 29.7 to 42.5) and 34.7% (95% CI: 28.4 to 41.0) at the patient level, respectively. The J48 method revealed a higher prediction of peri-implant health and disease with an accuracy of 0.871 compared with the logistic regression and MLP methods (0.832 and 0.852, respectively) for the present data set. In this specific patient population, the J48 model revealed the top-level node as "bleeding on probing (BOP)." "Maintenance therapy" and "medication use" were noted as powerful predictors in the next split-levels. Conclusion: The J48 model presented an acceptable predictive accuracy of peri-implant health and disease. The model revealed BOP as a major predictive clinical parameter when evaluated with possible risk factors for this patient population. Keywords: data mining, diagnosis, peri-implantitis, risk assessment, risk factors

Purpose: To evaluate the clinical, radiographic, and prosthetic outcomes of a single custom CAD/CAM abutment system on implants from four manufacturers, with a mean clinical service of 4 years in a retrospective, multicenter case series study. Materials and methods: Adult subjects (n = 142) previously restored with titanium or gold-shaded titanium nitride custom CAD/CAM abutments (Atlantis, Dentsply Sirona; n = 259) connected to implants from four different manufacturers (Dentsply Sirona Implants [AT], Biomet 3i [BM], Nobel Biocare [NB], Straumann [ST]), irrespective of implant-abutment interface, and replacing one or more teeth in any position were recalled for a single-visit examination by calibrated investigators at six university clinics. The primary outcomes evaluated included abutment success and survival; secondary outcomes included assessment of papillae fill, probing pocket depth (PD), bleeding on probing (BOP), marginal bone levels (MBLs), and patient-reported outcome measures (PROMs). Results: Two-hundred fifty-five (98.5%) abutments supported cement-retained restorations, and four (1.5%) abutments supported screw-retained restorations. Forty-two patients had 64 AT implants (25%), 31 patients had 61 BM implants (24%), 26 patients had 50 NB implants (19%), and 43 patients had 84 ST implants (32%). The overall implant-CAD/CAM abutment success rate was 92.66% (95% CI: 88.78%, 95.53%) for all implants examined, and the survival rate was 98.84% (95% CI: 96.65%, 99.76%) for all implants evaluated. The Jemt papillae index demonstrated a minimum of at least 50% to complete fill of the interproximal papillae in 65.0% of sites. PDs had a median value of 3.0 mm, and BOP was present on 19% of abutment surfaces. Mean MBL changes from the time of placement to exam were -0.24 ± 0.99 mm (-4.9 to 2.3; P = .058) for mesial sites and -0.32 ± 0.96 mm (-4.9 to 2.1; P = .000) for distal sites. PROMs expressed 93% of patients reporting good to very good masticatory function, 97% of patients reporting being satisfied or very satisfied with their esthetic outcomes, and 94% of patients indicating that they were satisfied or very satisfied with their overall implant-restorative outcomes. Conclusion: This retrospective, multicenter clinical study of FDA 510k-approved titanium CAD/CAM abutments of a single manufacturer on multiple implant systems demonstrated high levels of success and survival as well as stable peri-implant tissue outcomes, reflected by overwhelmingly positive PROMs. Keywords: clinical trial, custom abutment, implant-abutment interface, patient outcomes

Purpose: The purpose of this study was to compare the clinical influence of immediate individualized CAD/CAM healing abutments and conventional healing abutments on peri-implant soft and hard tissue in shaping the emergence profile. Materials and methods: Patients with a single maxillary incisor missing who accepted dental implantation were registered in this study. After implantation, individualized CAD/CAM healing abutments and regular prefabricated abutments were randomly inserted to shape the emergence profile. A radiograph was taken, and the pink esthetic score, papilla height, papilla proportion, and probing depth were recorded at 6 months after implant placement (T1), loading (T2, definitive restoration), and 1 year after loading (T3). Patient self-assessment scores were also evaluated through the visual analog scale. The data were analyzed statistically using the t test or repeated-measurements analysis of variance (ANOVA). Results: Twenty patients were enrolled in this study, including 9 patients using individualized abutments and 11 patients using conventional abutments. The mean total marginal bone level in the individualized abutment group was 1.53 ± 0.65 mm at implant placement, 1.10 ± 0.47 mm at loading, and 0.76 ± 0.47 mm at 1 year after loading. In contrast, the mean total marginal bone level in the conventional abutment group was 0.62 ± 0.39 mm at implant placement, 0.14 ± 0.55 mm at loading, and -0.04 ± 0.53 mm at 1 year after loading. The differences between the individualized abutment group and conventional abutment group were statistically significant for the mesial and distal marginal bone level at three time points, respectively (P ≤ .05). Similarly, there were significant differences in probing depth, papilla height, and pink esthetic score between the two groups. Conclusion: This immediately individualized healing abutment protocol may significantly preserve the peri-implant marginal bone and soft tissue. The use of individualized CAD/CAM healing abutments for shaping the emergence profile shows better esthetic outcomes than conventional healing abutments. Keywords: CAD/CAM, clinical research, dental implant, individualized abutment

Purpose: To investigate the clinical performance of implant-supported dental prostheses (ISDPs), this retrospective clinical study observed influencing factors on survival of the prostheses and necessary maintenance treatments during the observation time and complications of the dental implants. Materials and methods: Patients who were provided either with fixed implant-supported dental prostheses (FISDPs) or telescopic-retained removable implant-supported dental prostheses (TR-RISDPs) were included in this retrospective clinical study. Potential influencing factors on the survival probability of the prostheses were observed using Kaplan-Meier analysis: patient sex, type of prosthesis, location, dentition in opposing arch, participation in follow-up visits, and whether the patient had a previous history of oral cancer. The type and number of maintenance treatments and complications of dental implants were also analyzed. Results: A collective of 473 patients who were provided with either FISDPs (n = 320) or TR-RISDPs (n = 153) and 1,499 implants were included in the study. 6.6% of the prostheses (24 FISDPs and 7 TR-RISDPs) had to be replaced, and 6.3% of the implants (n = 45) were lost. The calculated 5-year survival probabilities were 87.4% for FISDPs and 95.5% for TR-RISDPs. FISDPs in patients who also had ISDPs in the opposing arch showed the lowest survival probabilities (P < .05). TR-RISDPs in patients who regularly attended follow-up visits showed the highest survival rates (P < .05). Maintenance treatments had to be performed at an earlier stage for patients with TR-RISDPs, and especially for TR-RISDPs located in the mandible (P < .05). Conclusion: FISDPs and TR-RISDPs showed good survival rates in this study. However, when planning FISDPs, the dentition in the opposing arch should be considered to prevent possible failure. TR-RISDPs indicate a higher need for aftercare measures, especially in the early years of function. Regular attendance of follow-up visits is still a decisive factor for success. Keywords: dental implant, dental prosthesis, implant-supported, Kaplan-Meier estimate, retrospective studies

Purpose: The purpose of this randomized controlled trial was to compare the surgical site infection rate with short (24 hours) vs extended (7 days) antibiotic prophylaxis for maxillary sinus floor augmentation surgery. Materials and methods: Eighty-five patients who were candidates for unilateral or bilateral maxillary sinus floor augmentation surgery were randomly assigned to short or extended antibiotic prophylaxis. Patients were evaluated on days 7, 14, 30, 60, and 180 after surgery for symptoms and signs of infection. The primary study endpoint was the development of surgical site infection up to day 180 postoperatively. Results: Patients underwent a total of 117 maxillary sinus floor augmentation surgeries, 62 in the short prophylaxis arm and 55 in the extended prophylaxis arm. Fifty-three patients (62%) had unilateral surgery, and 32 (38%) had bilateral surgery. Three patients developed a surgical site infection by 180 days postsurgery (overall rate, 2.6%): one patient (1.6%) in the 24-hour arm and two (3.6%) in the extended prophylaxis arm. All three patients received antibiotic treatment, and the infections resolved entirely. Conclusion: A low rate of surgical site infection was observed after maxillary sinus floor augmentation, and there was no apparent advantage to extended (7 days) vs short (24 hours) duration of antibiotic prophylaxis. The findings do not support the use of extended postprocedural chemoprophylaxis for patients undergoing maxillary sinus floor augmentation. Keywords: antibiotic prophylaxis, maxillary sinus floor augmentation, sinus elevation, surgical site infection

Purpose: This study aimed to test the effectiveness and reliability of the alveolar ridge-splitting technique in atrophic posterior arches, investigating the middle-term volumetric and clinical outcomes. Materials and methods: Atrophic alveolar ridges in the maxillary and mandibular posterior areas were treated with the alveolar ridge-splitting/expansion technique (ARST), immediate implant placement, collagen sponges covering the defect, and healing by secondary intention. Areas were rehabilitated by fixed dental prostheses supported by dental implants. Changes in volume and width of the alveolar ridge were retrospectively calculated by comparing the x-ray tomography scans obtained before and 5 years after surgery. Report of failure in the case sheets was taken into account. Cross-sectional images were also used to assess the thickness of the labial alveolar plates at the implant shoulder. Nonparametric analyses of variance with post hoc and pair-comparison tests were performed with a level of significance of .05. Results: A total of 38 patients were retrospectively selected (23 women and 15 men). Six patients underwent ARST surgeries in both the maxilla and the mandible and were excluded from statistical analysis. Differences between 16 maxillae and 16 mandibles and between 12 single crowns and 20 fixed partial dentures (FPDs) were searched. Episodes of minor swelling occurred within the first 2 days after surgery. Neither mucositis nor flap dehiscence had been registered. The mean values of buccal cortical thickness were 2.46 ± 0.49 mm and 1.15 ± 0.33 mm, respectively, in the maxillary and mandibular areas. After 5 years of survey, maxillary increases in alveolar ridge width and volume were +4.4 ± 0.4 mm and +295 ± 45 mm³, respectively, whereas the same outcome variables (+3.5 ± 0.7 mm and +217 ± 53 mm³) measured in the mandible appeared to be significantly smaller than those in the maxilla (P < .0001). One maxillary single implant failed. Cumulative survival rates at 5 years were 100% for mandibles and 95.5% (95% CI: 86.8% to 100%) for maxillae. Conclusion: Posterior areas of the maxilla displayed a higher increase in alveolar width and volume than mandibular areas, and even if it would be premature to draw survival conclusions at this stage without any statistical support, a lower cumulative survival rate was reported for the maxillary single implants. Keywords: alveolar ridge split, alveoloplasty, bone remodeling, posterior mandible, posterior maxilla, secondary intention healing

Purpose: To present clinical outcomes of alveolar ridge augmentation using in situ autogenous block bone and to compare the outcomes with previous studies. Materials and methods: The medical records of patients with a severe horizontal bone defect in a partially edentulous alveolar ridge (width < 3.5 mm), who received bone augmentation using in situ autogenous block bone, were retrospectively reviewed. After a 6-month or longer healing period, the augmentation effect was examined before implant placement. Cone beam computed tomography (CBCT) was performed before and after surgeries. The alveolar width of the bone grafts was measured on the CBCT images. Results: A total of 16 patients (22 grafts) were included. Graft exposure was seen in three grafts, which were classified as failed cases. The augmentation volume at implant placement in the failed cases was significantly lower than that of the successful cases. There were no significant differences in augmentation between anterior maxillary and mandibular implant sites. Conclusion: Autogenous bone grafting using in situ block bone is an effective and reliable approach for horizontal bone augmentation in the mandible and anterior maxilla that eliminates second donor site morbidity. Complete release of the buccal flap and tension-free suture is the key to avoiding wound dehiscence and ensuring the effectiveness of bone augmentation. Keywords: alveolar ridge augmentation, autogenous bone grafting, horizontal bone defect

Purpose: To evaluate retrospectively at 10 years the marginal bone levels around implants located in healed ridges or in extraction sockets and loaded immediately with provisional crowns fixed in prefabricated abutments. Materials and methods: Forty-two implants were placed in 36 patients needing single tooth replacement. Implants were inserted either in healed ridges (group 1) or in extraction sockets (group 2) and loaded immediately with prefabricated abutments. Two implants were lost during the healing period from group 2. The bone level around the implant shoulder was calculated mesially and distally on each implant using intraoral radiographs after crown cementation and 1, 3, 5, and 10 years following loading. Results: On the 10-year follow-up report, 36 implants were available for the clinical and radiologic evaluation. Besides the two implants lost during the osseointegration period, no implant loss was documented over the 5- to 10-year observation period. The average bone loss after implant and crown cementation was 0.266 ± 0.176 mm for 1 year, 0.194 ± 0.172 mm for 5 years, and 0.198 ± 0.165 mm for 10 years in healed ridges and 0.267 ± 0.161 mm for 1 year, 0.213 ± 0.185 mm for 5 years, and 0.287 ± 0.194 mm for 10 years in extraction sockets. Three crowns (in group 1) and one crown (in group 2) were replaced for esthetic reasons. Conclusion: The outcome of this study revealed that in both groups, the responses of marginal bone were similar. Immediate placement of the definitive prefabricated abutment in an immediate loading protocol appears to conserve marginal bone around the implant neck. Keywords: extraction socket, healed socket, immediate loading, marginal bone level, maxilla, single-tooth implant

Purpose: To describe the postoperative complications following lateral wall sinus augmentation using (poly L-lactideco-ε-caprolactone; PLCL) and natural polysaccharides polymers-coated bovine bone (PBB). The secondary aims were to examine histologic findings and to propose complication management alternatives. Materials and methods: This retrospective study included 61 subjects who underwent 67 lateral wall sinus augmentation procedures using PBB in the standard protocol. In cases that presented complications, treatment included additional antibiotic therapy, implant removal, or sinus reentry and total removal of the grafting material. In three cases, biopsy specimens were taken from the sinuses, and histologic analyses were performed. Results: The prevalence of postoperative complications was 32.8% (22 of 67 cases) in 18 of the patients (29.5%). The most prevalent symptoms were persistent pain (68.2%), swelling (63.6%), and oroantral fistula (54.5%). Radiographic signs appeared in 45.5% of the complications. A total of 24 implants failed; thus, an overall 80.3% survival rate was established at 19 months. The vast majority of complications (86.4%) were treated eventually with reentry surgery and revealed that the sinus was full with granulation tissue surrounding pieces of a nonossified rubber-like material. In cases where implants were placed, nonosseointegrated implants were surrounded by soft tissue. The sinus was cleaned thoroughly; the graft material remnants were removed together with inflamed parts of the sinus membrane, followed by chlorhexidine and saline lavages. In the biopsy specimens taken from the sinus cavity, there were no histologic features of new bone formation around the grafted material. Conclusion: Lateral wall maxillary sinus augmentation using PBB was associated with an acute sinus infection histologic appearance and with a 7-times-higher failure rate compared with previous reports. This serious adverse event suggests that PBB cannot be recommended for maxillary sinus augmentations. Keywords: complication, implant failure, infection, graft failure, PLCL (poly L-lactide-co-ε-caprolactone) coated bovine bone, sinus elevation

Purpose: To evaluate studies with a minimum follow-up of 3 years to find the peri-implant marginal bone loss (MBL) and rate of implant failure with platform-switching (PS) and platform-matching (PM) implant-abutment connections. Materials and methods: A systematic review and meta-analysis was done based on the preferred reporting items for systematic reviews and meta-analyses guidelines, with a focused question on population, intervention, comparison, and outcome. The Cochrane Collaboration's Risk of Bias tool was used to assess bias. Randomized controlled trials (RCTs) comparing peri-implant MBL and implant failure in patients receiving PS implants and PM implants only were included. The risk ratio (RR) of the implant-abutment connection and implant failure was calculated, and peri-implant MBL was expressed in mean differences (MD) at 95% confidence intervals (CIs). Results: Three hundred eighty-one articles were obtained after an initial literature search. Finally, nine articles were included in the study that fulfilled the inclusion criteria. Four hundred twenty-six PS and 411 PM implants were placed with 16 implant failures (8 PS and 8 PM). The implant survival rate was 98.12% for the PS group, and 98.05% for the PM group, with no statistically significant difference (P = .97). The mean peri-implant MBL with the PS implant was lower (0.33 ± 0.41 mm) compared with the PM implant (0.66 ± 0.42 mm). A significant effect of PS implants was found in reducing peri-implant MBL (MD: -0.70, 95% CI: -1.25,-0.15; P = .01) compared with PM implants. The MD of peri-implant MBL between the PS and PM implants decreases with increased follow-up: MD of 0.69 (P = .15) with follow-up of ≥ 3 years but < 5 years, and MD of 0.62 (P = .04) with follow-up of ≥ 5 years. Conclusion: Reduced peri-implant MBL was found with the PS concept. The peri-implant MBL decreases with an increased mismatch between the abutment and implant platform. The difference in peri-implant MBL in PS and PM implants in the maxilla was greater and favored the PS concept. Bone-level implants with single crowns or splinted prostheses better preserved the peri-implant marginal bone with the PS concept. Keywords: dental implants, meta-analysis, peri-implant marginal bone loss, platform matching, platform switching

Purpose: A review was done to evaluate the effect of implantoplasty on surface roughness, biofilm formation, and biocompatibility of dental implants. Materials and methods: Electronic searches were done in PubMed (OVID), Scopus, Web of Science, and The Cochrane Library to identify all relevant articles published until April 2020. All publications evaluating changes in implant surfaces after implantoplasty were included. The primary outcome variable was roughness of the implant surface. Secondary outcome variables were biofilm elimination and regrowth, changes in surface elements, and cell viability. Results: A total of 11 in vitro studies and two in vivo publications were included. Implantoplasty reduced surface roughness of the implant. The final outcome depended on the bur protocol, with tungsten carbide burs providing the smoothest surfaces, followed by silicone polishers. Implantoplasty did not affect cell viability, and roughness was inversely correlated to human gingival fibroblast growth. The technique also proved effective in removing biofilm and preventing its regrowth. Conclusion: Implantoplasty reduces the surface roughness of dental implants, which in turn inhibits biofilm formation without affecting the biocompatibility of titanium implants. Since most of the included studies were done in an in vitro setting, further clinical trials are necessary to confirm these outcomes. Keywords: biofilm, implantoplasty, peri-implantitis, surface roughness, systematic review

Purpose: Dynamic navigation is a technique that allows for the placement of dental implants using a computer-guided approach according to preoperative planning. Its accuracy has been assessed in several previous studies. The purpose of this study was to summarize data on implant placement accuracy using dynamic navigation, to synthesize the frequency of intraoperative complications and implant failures, and to compare this technique with static computer-guided surgery and a freehand approach. Materials and methods: Electronic and manual literature searches until December 2019 were performed. The outcome variables were implant placement accuracy using dynamic navigation, accuracy differences between dynamic and static techniques and between dynamic and freehand techniques, intraoperative complications, and implant failures. Random-effects meta-analyses were performed. Results: A total of 32 studies were included; 29 reported accuracy values (2,756 implants), and 10 focused on complications and implant failures (1,039 implants). The pooled mean implant placement errors were 0.81 (95% CI: 0.677 to 0.943) mm at the entry point and 0.910 (95% CI: 0.770 to 1.049) mm at the apical point. The pooled mean vertical and angular deviations were 0.899 (95% CI: 0.721 to 1.078) mm and 3.807 (95% CI: 3.083 to 4.530) degrees. The navigation group showed significantly lower implant placement errors with respect to the freehand technique (P < .01) and similar accuracy values (P ≥ .05) compared with the static technique. The pooled prevalence of failures was 1% (95% CI: 0.00% to 2%). Conclusion: Dynamic navigation provided small implant placement errors, comparable with those obtained using static computer-guided surgery, and can be considered a more accurate technique than conventional freehand surgery. Keywords: accuracy, computer-guided surgery, dental implants, dynamic navigation