The International Journal of Oral & Maxillofacial Implants, 02/2022

Purpose: This systematic review aimed to assess the clinical efficacy of antibiotics when used as an adjunct in treating peri-implant diseases. Materials and methods: A systematic search of papers published between January 1980 and March 2020 was conducted. Randomized clinical trials with at least 10 patients who had peri-implant diseases, treated with or without adjunctive antibiotics in combination with surgical or nonsurgical therapies, and with a minimum of at least 3 months of follow-up were included. Meta-analyses were conducted to analyze weighted mean differences in probing depth reduction, radiographic bone level gain, and odds ratio of treatment success. Results: From the 856 articles identified, 10 articles met the inclusion criteria and were selected. Of these, 7 articles were used for the meta-analysis. The adjunctive use of antibiotics in the treatment of peri-implant diseases yielded significantly greater probing depth reduction (weighted mean differences = 0.56 mm at 3 months, P = .001; 0.77 mm at 6 months, P < .00001; 0.92 mm at 12 months, P < .00001), radiographic bone level gain (weighted mean differences = 0.64 mm, P = .03), and treatment success (odds ratio = 1.74, P = .04) compared to the same treatment without antibiotics. Conclusion: Based on the existing evidence, the use of adjunctive antibiotics to treat peri-implant diseases, especially peri-implantitis, provided potential benefits in clinical outcomes for up to 12 months posttherapy. Keywords: antibiotics, dental implant, meta-analysis, peri-implantitis, systematic review

Purpose: The exposure of nonresorbable membranes following alveolar bone augmentation is one of the most frequently occurring complications. This review aimed to investigate the treatments that can be adopted to manage the exposure of polytetrafluoroethylene-based membranes (PTFE-ms) and titanium meshes (TMs) and their outcomes. Materials and methods: Two independent reviewers electronically and manually searched the EMBASE, PubMed/MEDLINE, Scopus, and Cochrane bibliographic databases to retrieve pertinent articles available between January 2000 and March 2021. Only human studies describing the type of treatment and the soft tissue outcome following exposure of PTFE-ms or TMs were included. Results: Overall, 11 articles in the PTFE-ms group and 24 in the TM group were included for data analysis. Results indicated that, in both groups, two distinct therapeutic strategies are mostly applied in case of exposure, namely, pharmacologic and mechanical treatments. Other options have been identified seldomly. Statistically significant evidence of an association between the type of barrier membrane and the exposure rate (28.7% vs 38.5% for TMs and PTFE-ms, respectively; P = .019) and between the type of exposed device and the treatment outcome in terms of removal rate following therapy (11.9% and 44.4% for TMs and PTFE-ms, respectively; P < .001) was noted. Conclusion: In both groups, chlorhexidine applications and meticulous plaque control may lead to improved healing conditions after exposure. Surgical removal of the exposed portion can be considered to promote secondary intention healing. The beneficial effects of systemic antibiotics could not be demonstrated in the management of the exposure but should be evaluated in case of graft infection. Keywords: barrier membranes, bone regeneration, complications, dental implants, titanium mesh

Purpose: This systematic review and Bayesian network meta-analysis (NMA) were performed to compare the clinical effects of nonaugmentative adjunctive approaches in the surgical treatment of peri-implantitis. Materials and methods: A systematic search of six electronic databases was performed up to June 20, 2020. Additional relevant literature was identified through gray literature and hand searches. Randomized controlled trials (RCTs) of surgical treatment of periimplantitis with nonaugmentative adjunctive approaches were included. Probing depth (PD) changes, marginal bone level (MBL) changes, and treatment success rates were extracted and assessed. Pairwise meta-analysis and Bayesian NMA were performed. This review was registered at PROSPERO (CRD42020191113). Results: The search yielded 7,419 articles, of which 10 studies with 11 articles were included in the quantitative analysis. In the NMA of mechanical approaches and photodynamic therapy (PDT), compared with hand curettes, implantoplasty provided significant additional PD improvement at the 6-month follow-up evaluation (mean difference [MD]: 1.29; 95% confidence interval [CI]: 0.17, 2.38) and 12-month follow-up evaluation (MD: 1.39; 95% CI: 0.91, 1.74). In the NMA of antiseptics and systemic antibiotics, adjunctive use of antiseptics and/or systemic antibiotics did not provide significant improvement in PD or MBL. In the NMA of all adjunctive approaches, no significant differences were found in PD improvements. Conclusion: Within the limitations of this systematic review and NMA, implantoplasty is more effective than hand curettes in improving PD in the surgical treatment of peri-implantitis. Chemical antiseptics or systemic antibiotics have a limited effect on improving PD and MBL. Keywords: network meta-analysis, peri-implantitis, surgical procedures, systematic review

Purpose: The objective of this study was to determine the effect of two antibiotics (amoxicillin and clindamycin) and one antiseptic (chlorhexidine digluconate [CHX]) on the growth and differentiation capacity of primary human osteoblasts. Materials and methods: Osteoblast proliferation was determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) technique after a 1-minute treatment with 400 μg/mL amoxicillin or 150 μg/mL clindamycin or CHX (0.12% or 0.2%). Flow cytometry was used for apoptosis/necrosis analysis. The study of cell differentiation was performed using a mineralization medium and staining of the nodules formed using red alizarin at 15 and 22 days of treatment with 400 μg/mL amoxicillin or 150 μg/mL clindamycin. Spectrophotometry was used to determine alkaline phosphatase (ALP) activity after 1 minute of treatment. Results: Treatment of osteoblasts with 0.12% and 0.2% CHX for 1 minute induced a strong dose-dependent reduction in cell proliferation (P < .001) with a significant increase in the percentage of apoptotic cells (P = .004 and < .001, respectively). However, cell proliferation significantly increased (P < .05) after treatment with 150 μg/mL clindamycin. Treatment of the osteoblasts with 150 μg/mL clindamycin for 1 minute significantly increased the expression of ALP (P = .002). Calcium deposition was significantly higher (P < .001) in the 150 μg/mL clindamycin group. Conclusion: These data support the use of low doses of clindamycin and amoxicillin for intraoral bone graft decontamination and raise questions about the use of CHX. Osteoblast growth and differentiation may be favored by low doses of clindamycin, and it may be the decontaminant of choice for intraoral bone grafts, while CHX is shown as a less bone-friendly agent. Keywords: amoxicillin, bone decontamination, chlorhexidine, clindamycin, low-speed drilling

Purpose: To evaluate the effects of coarse microcavities added to micron and submicron rough implant surfaces in the implant-bone anchorage in rabbits. Materials and methods: Confocal interferometry was used to quantify roughness. Electron microscopy and energy-dispersive x-rays characterized the surfaces prior to and after implantation. X-ray photoelectron spectroscopy and contact angle determined the surface chemistry and energy, respectively. Fifteen New Zealand White rabbits received, respectively, one cavity-less (C-) and one cavity-rich (C+) implant per femoral condyle and were allowed to integrate for 2 and 8 weeks. The bone-to-implant contact (BIC), bone volume density (BVD), and removal torque (RTQ) were then analyzed. Results: The cavities produced on the surfaces were 48.4 ± 16.8 μm in diameter and 37.8 ± 36.5 μm deep (5.9% ± 1.1% surface coverage). C+ did not alter the surface chemistry or energy. In vivo, C+ implants produced more BIC and RTQ at 8 weeks (P = .002 and P = .059, respectively) and more BVD at 2 and 8 weeks postimplantation (P = .031 and P = .078, respectively). Bone tissue was observed inside the cavities of C+ both histologically and by scanning electron microscopy after implant removal. Conclusion: Unevenly distributed coarse cavities within a micron and submicron rough surface allow bone ingrowth and increase implant stability and bone-surface unions in rabbits. These results encourage the design of implants with multilevel surface topographies to improve implant-based regeneration. Keywords: animal model, dental implants, osseointegration, surface properties, topography

Purpose: The aim of this study was to evaluate and compare the effect of changing five macrostructural design parameters of dental implants on the peak strains experienced by the interfacial bone. Materials and methods: Five geometric variables, including three body-related (implant length, diameter, and taper) and two thread-related (thread depth and thread angle) parameters, were defined. The alveolar bone was modeled as a block with anisotropic and linearly elastic properties with 20-mm height and 12-mm buccolingual and mesiodistal dimensions. Oblique occlusal loads (100-N vertical and 20-N horizontal) were applied to the abutment surface. A total of 162 models with different designs were defined by implementation of a full-factorial design. The peak values of the compressive and tensile principal strains in the cortical and cancellous bones were calculated by finite element analysis (FEA). Results: Implant diameter and length had maximum and minimum effects on the peak compressive and tensile strains at the cortical interface, respectively. Implant diameter and thread depth had maximum and minimum effects on the maximum compressive strain at the cancellous interface, while thread angle and length had maximum and minimum significant effects on the maximum tensile strain at the cancellous interface. Conclusion: The interaction of thread parameters and taper has the greatest effect on the peak compressive and tensile strains at the cancellous interface and also on the peak tensile strain at the cortical interface, while body-related parameters are more effective on the peak compressive strain at the cortical interface. Keywords: bone-implant interface, cancellous bone, cortical bone, dental implant, finite element analysis, mechanical strain

Purpose: To evaluate implant osseointegration in grafted autogenous bone blocks fixed with cyanoacrylate-based adhesive and screws. Also, grafted bone fixed either with an adhesive or screw was evaluated. Materials and methods: Two surgical defects in the parietal region of rabbits (n = 12) were performed in each animal. Autogenous bone blocks obtained were fixed anteriorly with a screw or cyanoacrylate-based adhesive. After 30 and 45 days of grafting procedures, implants were placed in bone blocks. Histomorphometric and microcomputed tomography (micro-CT) analyses of the implant area were performed at 30 days after implant surgery in the screw (n = 6) and adhesive (n = 6) groups. Histomorphometric analyses of bone-grafted areas were performed at 60 and 75 days in the screw (n = 6) and adhesive (n = 6) groups. Histomorphometric evaluations were carried out in implant and grafted bone areas. The micro-CT parameters evaluated were bone-to-implant contact, bone area fraction occupancy, bone volume fraction, trabecular thickness, trabecular separation, and trabecular number. Results: No differences were observed in the micro-CT parameters for the screw and adhesive groups in all experimental periods. However, an increased quantity of immature bone volume was observed on the adhesive group in the grafted area after 75 days. The grafted area in the screw group (75 days) presented a decrease in the volume density of the immature bone compared with the screw group (60 days). There were no differences in both groups and experimental periods in soft tissue in the grafted area. Conclusion: No differences were observed in the osseointegration of implants placed in grafted autogenous bone blocks fixed with cyanoacrylate-based adhesive and screws. Therefore, osseointegration in autogenous bone fixed with cyanoacrylate-based adhesive is viable. Keywords: bone remodeling, bone transplantation, cyanoacrylates, dental implants, osseointegration

Purpose: To determine the effect of 0.7- and 2.4-mm transmucosal abutment height titanium bases on the crestal bone stability and peri-implant soft tissue condition of bone-level implants with platform switching in patients with vertically thick soft tissues. Materials and methods: Sixty bone-level platform-switched implants were placed in the molar and premolar regions of both arches in 60 patients. All epicrestally inserted nonsubmerged implants had a 4.1-mm diameter and, after osteointegration, were randomly allocated into two groups: (1) the short group, with a titanium base of 0.7-mm transmucosal abutment height, and (2) the high group with a 2.4-mm height. Monolithic zirconia restorations were fabricated for all implants. Parallel intraoral radiographs were obtained after the delivery of restorations (T1) and after 1 year (T2). Crestal bone levels and peri-implant soft tissue conditions were calculated for each implant. The significance level was set at α = .05. Results: After 1 year, 55 patients were evaluated, with a mean bone loss of 0.6 ± 0.51 mm (median: 0.71, range: 0 to 2.09 mm) in the short group (23 patients) and 0.45 ± 0.59 mm (median: 0.65, range: 0 to 2.12 mm) in the high group (22 patients), showing no significant difference between groups (P = .168). A significant increase in marginal bone height was noted between the T1 and T2 time points in the short and high (P = .029 and .001, respectively) groups. The peri-implant soft tissue health parameters did not show statistically significant differences. Conclusion: Crestal bone stability after 1 year of follow-up around epicrestally placed platform-switched implants is not influenced by transmucosal abutment height, if the vertical soft tissue thickness is ≥ 3 mm. Keywords: prosthodontics, randomized controlled clinical trial, single implant

Purpose: The scarce standard therapeutic protocols for the management of peri-implant diseases results in the empirical application of therapeutic modalities. The objective of this study was to carry out a survey to analyze the therapeutic trends of professionals with different academic backgrounds and levels of expertise. Materials and methods: An exploratory cross-sectional internet-based study survey of board-certified members of the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP) was conducted. To assess the therapeutic trends, four clinical vignettes representing different scenarios of peri-implant biologic complications were provided to the participants. Differences in practice patterns were determined using chi-square test and Student t test or analysis of variance (ANOVA) test for qualitative variables. Results: A total of 268 members of the AAP and EFP completed the survey. A significant difference in preferred treatment plan was found between EFP and AAP periodontists, resective therapy being the treatment of choice by the majority of the former (41.2%) and regenerative therapy by the latter (48.9%; P < .001). Overall, 48.1% of experts did not consider any intervention for the management of mucositis. Antibiotic prescriptions differed among groups, with statistical significance in each clinical case, and the explantation criteria were inconsistent and differed significantly among groups. Conclusion: Substantial variations exist concerning the decision-making to manage peri-implant diseases and conditions. Keywords: diagnostic procedure, peri-implantitis, periodontist, periodontology, surgical procedure

Purpose: To evaluate the use of a new resin metal opaquer on the surface of titanium abutments, in combination with two luting agents, and its effect on the retentive strength of implant-supported zirconia copings. Materials and methods: Sixty customized titanium abutments were designed and fabricated with virtual design software and a milling machine. Thirty abutment specimens were coated with metal opaquers, and the others were not coated. Then, the titanium abutments were fitted into the implant analogs, and the abutment-implant analog complexes were embedded in acrylic resin blocks. Sixty CAD/CAM-fabricated zirconia copings were seated on the abutments and secured with glassionomer cement or self-adhesive resin cement. The specimens were stored in 100% humidity for 1 hour and artificial saliva for 23 hours at 37°C before thermocycling for 5,000 cycles of 5°C to 55°C with a 30-second dwell time. The retentive strength was measured using a pull-out test with a universal testing machine. The dislodgment forces were statistically analyzed via two-way analysis of variance (ANOVA). The failure modes were evaluated and categorized by examining the fracture surface. Results: The metal opaquer material had a significant negative effect on retention of zirconia copings. The nonopaquer titanium abutments showed significantly (P < .05) higher retentive strength than the metal opaquer abutments. Comparing the cements, the retentive strength values of self-adhesive resin cement were significantly higher than those of glass-ionomer cement. The metal opaquer groups exhibited mostly mixed-type failures, a combination of adhesive failures and cohesive failures, whereas the nonopaquer groups showed mostly adhesive-type failures. Conclusion: The titanium abutments coated with the new metal opaquer material resulted in a reduction of retentive strength. Self-adhesive resin cements exhibited significantly higher retention than glass-ionomer cements. Keywords: dental abutment, opaque resin, retentive strength, titanium, zirconia

Purpose: Comprehensive rehabilitation in patients with severe periodontal destruction may require the use of dental implants. The primary aim of this study was to evaluate bone volume changes in periodontally compromised patients over a 12-month follow-up period after immediate full-arch implant reconstruction of the mandible. The secondary aim was to evaluate the repeatability of 3D bone volume change measurement methods around dental implants. The null hypothesis was that bone volume would decrease in the first year after delivery of the definitive prosthetic reconstruction. Materials and methods: This retrospective study analyzed CBCT scans of 16 patients before and after computer-guided immediate full-arch implant reconstruction of the mandible. The bone volume change in the mandibular body and around the implants and the peri-implant bone area in coronal and axial cross sections were calculated. Results: The average bone gain for the mandibular body was 3.3% ± 1.8%. The average bone volume increase in the peri-implant area was 23.2% ± 16.7%. The interobserver and intraobserver ICC values for 3D measurements were high (> 0.85). Conclusion: The null hypothesis was rejected. Both mandibular body and peri-implant surroundings undergo bone remodeling in the form of bone gain over 12 months after immediate implantation. Keywords: computer-guided surgery, cone beam computed tomography, dental prosthesis, immediate loading, implantsupported, periodontitis

Purpose: To determine clinical parameters, histologic features, and radiographic linear bone width changes of regenerated bone using different biomaterials for ridge preservation following tooth extraction. Materials and methods: For this pilot study, five patients were grafted with anorganic bovine bone and collagen plus recombinant human platelet-derived growth factor-BB (rhPDGF-BB), five patients were grafted with anorganic bovine bone and collagen alone, and five patients did not receive any biomaterial (control) after tooth extraction. Clinical, histologic, and radiographic evaluations were carried out 4 months postextraction. Results: Differences in terms of buccolingual width were found when comparing the control group to the group grafted with anorganic bovine bone and collagen plus rhPDGF-BB (P = .012). No statistical differences were observed between the groups in terms of mineralized or nonmineralized tissue formation or in terms of the number of osteoblasts or osteocytes per mm2 after 4 months of healing. Interestingly, the number of vessels in the grafted area was found to be significantly different among the three groups (P = .005). The number of Musashi-1 positive cells was also different among groups, both in the mineralized and the nonmineralized areas of the grafted bone (P = .024 and .005, respectively). Conclusion: Anorganic bovine bone with bovine collagen is an efficient biomaterial to avoid postextraction resorption of the alveolar ridge. The addition of rhPDGF-BB appears to improve the biologic features of the newly formed bone and decrease bone resorption; further studies are needed for confirmation.

Purpose: The aim of this case-control study was to investigate the occurrence of bleeding events related to maxillary sinus elevation with a lateral window in patients under direct oral anticogulant therapy. Materials and methods: Seventyseven consecutive patients were scheduled for unilateral maxillary sinus floor elevation using a lateral window approach. Participants were divided into two groups: group A, formed by 37 patients who were under novel oral anticoagulation therapy (rivaroxaban/apixaban), and a control group, composed of 40 healthy subjects. Within group A, assumption of direct oral anticoagulants was not suspended nor modified before surgical procedures. Time (early/delayed) and site (intraoral/extraoral) of bleeding episodes were recorded in both groups of patients, in addition to bleeding severity (mild, moderate, or severe). Results: Maxillary sinus floor elevation was performed in all patients. One dropout happened due to intraoperative membrane perforation. Overall bleeding episodes were comparable in both groups, chi-square (1) = .68, P = .41. Early intraoral bleeding events were more common in absolute terms, but also occurred with approximately the same frequency in both group A and the control group (Fisher exact tests: P = 1.00 and P = .375, respectively). No severe bleeding was observed in any of the attended patients. Conclusion: Within the limitations of this case-control study, maxillary sinus floor augmentation with a lateral window approach can be safely administered to patients who are under direct oral anticoagulation therapy when specific recommendations are instituted. Keywords: apixaban, bleeding, maxillary sinus floor augmentation, rivaroxaban

Purpose: To evaluate the efficacy of autogenous particulate dentin as a bone substitute to maintain dimensional volume in human socket preservation procedures. Materials and methods: Particulate dentin was used in socket site preservation procedures. The extracted natural tooth was ground to particles 250 to 1,200 μm in size to fill the socket site. At 6 months, during the implant placement stage, hard tissue biopsy specimens were harvested by a 2.5-mm cylindrical trephine bur for the histologic analysis. Histomorphometry was carried out with ImageJ software to calculate direct bone to grafted dentin particles contact, newly formed bone, and particulate dentin area fractions. Results: Fifteen patients went through the socket preservation procedure using particulate dentin as the grafted bone substitute. De novo bone formation filled the entire grafted area. Newly formed bone was observed throughout the entire grafted area, particularly around the grafted dentin particles. The majority of particles were surrounded by direct contact with newly formed osseous tissue enriched by osteocytes. Newly formed bone ankylosed to particulate dentin and became a solid matrix preserving the ridge dimension. Histomorphometric measurements showed that the new bone formation area fraction was on average 38.4% ± 16.5%, while the residual particulate dentin showed an average of 29.9% ± 14.4%, and 31.7% ± 14.2% was captured by the connective tissue component. Particulate dentin was in direct contact with newly formed bone at an average rate of 69.1% ± 22.8%. Conclusion: Particulate dentin showed complete biocompatibility and high osteoconduction. Thus, it can be used as an appropriate grafting biomaterial to maintain socket site volume dimensionally for subsequent implant placement procedures. Keywords: autogenous dentin particles, bone graft substitute, ridge augmentation, socket site preservation

Purpose: The exact etiopathogenesis of peri-implant diseases remains unclear. While significant information on molecular markers is available, studies on biomarkers related to possible biocorrosion are sparse. This study aimed to evaluate periimplant crevicular fluid (PICF) for possible titanium (Ti) contamination and explore associations between clinical findings, inflammatory mediators, and Ti levels. Materials and methods: Patients with implant-supported restoration (≥ 1 year in function) were recruited for this cross-sectional study. Demographics, systemic, and periodontal health history were recorded. Clinical evaluations were conducted to reach peri-implant/periodontal diagnoses and grade severity of peri-implant soft tissue inflammation. Crevicular fluid (CF) was collected from both implants and adjacent teeth (PICF, gingival crevicular fluid [GCF]) and analyzed for Ti (inductively coupled plasma mass spectrometry) and inflammatory mediators (V-plex assays). Multiple regression analysis with a linear mixed effect model was used to analyze possible associations between clinical diagnosis, PICF/GCF cytokine, and Ti concentrations. Results: Seventy-seven patients (aged 62 ± 2 years; 39 male) with 117 implants (9 ± 1 years in function) were recruited. Diabetes, positive periodontitis history, and current/former smoking were reported by 8%, 39%, and 39% of subjects, respectively. Seventy-nine implant sites (63 patients) were included in CF cytokine analysis, and 45 of these sites (42 patients) were paired with Ti analysis. Statistically significant increases from health to disease were noted in log-transformed PICF concentrations of IL-1β, IL-6, IL-10, and INF-γ (P ≤ .05). Also, statistically significant increases from health to severe clinical inflammation were detected in log-transformed PICF concentrations of IL-8, IL-13, and TNF-α (P ≤ .05). Ti was detected in the majority (82%) of PICF and GCF samples. There was no statistically significant difference in log-transformed Ti concentration based on disease status. However, log-transformed Ti concentration was positively correlated to IL-1β, IL-2, IL-4, IL-8, IL-13, and INF-γ concentrations when data were adjusted for site-specific health (P ≤ .05). Conclusion: Ti was detectable in PICF and adjacent GCF, even in health. Specific inflammatory mediator concentrations were increased in peri-implant disease and significantly associated with Ti concentrations, even when data were adjusted for peri-implant health status. Increased GCF inflammatory mediator concentrations were also associated with increased Ti concentrations. Ti effects on peri-implant as well as periodontal tissues require additional longitudinal investigations. Keywords: crevicular fluid, cytokine, etiology, pathogenesis, peri-implantitis, titanium

Purpose: This study aimed to investigate the effect of attachment type, maximum occlusal force, denture deformation, and other confounding factors on marginal bone loss of two-implant overdentures after 1 year. Materials and methods: Ninety edentulous patients received two implants in canine areas of the mandible using the computer-guided flapless surgical technique. Three months later, overdentures were connected to the implants with bar, resilient telescopic, and resilient stud attachments. Marginal bone loss was evaluated using standardized digitized periapical radiographs. Maximum occlusal forces were evaluated using a digital bite-force meter. Denture base deformation (denture strains, μm) was evaluated using strain gauges bonded to the polished surface of the denture at the level of the attachments. Regression analysis was adopted to find the relation between marginal bone loss and the following confounders (age, sex, mandibular bone height, period of edentulism, number of previous dentures, attachment type, maximum occlusal force, and denture strains). Results and conclusion: Telescopic overdentures showed the highest marginal bone loss and maximum occlusal force, followed by bar overdentures, and stud overdentures demonstrated the lowest values. The highest denture strains were noted with bar overdentures, followed by telescopic overdentures, and stud overdentures showed the lowest strains. Age (P = .022), mandibular bone height (P = .023), number of previous dentures (P = .004), maximum occlusal force (P ≤ .001), and denture strains (P = .048) were significantly correlated with marginal bone loss. For every 1-year increase in age, there was a decrease in bone loss by 0.3%. For every 1-mm increase in bone height, there was an increase in bone loss by 1%. For every one increase in the number of worn dentures, there was a decrease in bone loss by 4.2%. For every 10-N increase in maximum occlusal force, there was an increase in bone loss by 6.4%. For every 10-μm increase in denture strains, there was an increase in bone loss by 0.21%. Sex, time of edentulism, and attachment type did not demonstrate a significant correlation with marginal bone loss. Keywords: attachment, denture deformation, implant, marginal bone loss, maximum occlusal force, overdentures

Purpose: To describe the benefits of covering the extrasinusal length of extramaxillary zygomatic implants with a pedicled buccal fat pad flap through a tunnel approach. Materials and methods: Four extramaxillary zygomatic implants were placed in 10 patients and loaded immediately with an acrylic provisional fixed prosthesis. The extrasinusal length of every implant was covered with a pedicled buccal fat pad flap. Study variables were implant survival rate, peri-implant soft tissue recession (PISTR), peri-implant soft tissue condition (PISTC), modified Bleeding Index (mBI), and suppuration. The statistical analysis comprised the Brunner-Langer model of longitudinal data for each variable and the analysis of variance to assess main effects and interactions. Results: All the zygomatic implants showed osseointegration, resulting in a survival rate of 100%. The PISTR was evaluated after surgery (T0) and after 12 months (T1), statistically significant differences being observed (P = .014). Recession also depended on specific implant positioning; zygomatic implants in the anterior were found to have a higher risk of recession vs implants in the posterior (P = .065). The PISTC was assessed at T0 and T1, and no statistically significant changes were observed (P = .718). Bleeding on probing was present in 10% of the implants at T0 and in 15% at T1, the difference being nonsignificant (P = .317). Conclusion: The use of a pedicled buccal fat pad flap to cover the extrasinusal length of extramaxillary zygomatic implants appears to reduce the risk of soft tissue recession and exposure of the implant surface to the oral cavity. Keywords: buccal fat pad, oral and maxillofacial, zygomatic implant

Purpose: This study aimed primarily to examine the relationship between maxillary sinus variations and dental implant placement in the atrophic maxillary premolar-molar region. Secondly, the preferences of experienced clinicians with regard to implant length in the bone and sinus were evaluated. Materials and methods: The data were collected from panoramic radiographs of patients who had undergone dental implant surgery in the posterior maxilla. Parameters such as sinus pneumatization level, sinus floor elevation operation type, and length of dental implants in the sinus and bone (in millimeters) were evaluated. Groups were created for the categories mild-moderate-medial pneumatization and severe-extreme-medial pneumatization, with the subgroups severe and extreme medial pneumatization for medial pneumatization and "5 to 10 mm" and "≤ 5 mm" for inferior pneumatization of the maxillary sinus. The distribution of the data was evaluated with the Shapiro-Wilk test, and the Mann-Whitney U test was used to evaluate the millimeter measurements made in the groups. Results: The mean implant length in bone tissue was measured as 6.3 mm in the mild-moderate-medial pneumatization group and 5.4 mm in the severe-extreme-medial pneumatization group (P < .001), whereas the mean implant length in the sinus was 3.6 mm in the mild-moderate-medial pneumatization group and 3.9 mm in the severe-extreme-medial pneumatization group, respectively (P < .001). The mean implant length in the sinus was 3.0 mm in the 5 to 10 mm group and 5.1 mm in the ≤ 5 mm group (P < .001), whereas the mean implant length in bone was measured as 6.6 mm in the 5 to 10 mm group and 3.6 mm in the ≤ 5 mm group (P < .001). Conclusion: This was the first study in the literature in which classifications of inferior and medial pneumatization of the maxillary sinus were used for the same implants and their correlation was evaluated in the presence of sinus pneumatization. In this study, the mean implant length in the sinus was measured to be greater as sinus pneumatization progressed medially. Therefore, like inferior pneumatization, medial pneumatization may also have risks attributable to the need for internal or external sinus elevation operations in the atrophic maxilla, and this could be easily underestimated if CBCT is not used. Keywords: cone beam computed tomography, dental implants, paranasal sinuses

Purpose: Titanium and zirconium wear are discussed in the literature as contributing factors for mechanical complications. The purpose of this study was to evaluate if current implant designs present visible clinical evidence of surface damage after insertion and removal in dense bone and if these changes are comparable in titanium and zirconia implants. Materials and methods: For this experimental in vitro and pilot study, four implant systems were evaluated. Astra Tech Implants (Dentsply Sirona), Nobel Biocare Implants (Nobel Biocare), Straumann Implants (Institut Straumann), and Zeramex Implants (Dentalpoint). Six implants of each group with similar lengths (between 10 and 11 mm) and diameters (between 4.0 and 4.5 mm) were used. Protocols for implant bed preparations in dense bovine bone disks represented type II bone density. The implants were inserted and removed to evaluate the changes experienced by their surfaces using a magnification compatible with 5× magnification of the clinical setting. The presence or absence of damage and type of damage were evaluated at the coronal, middle, and apical regions at higher magnification. The Cochran Q test for binary dichotomous samples was used for statistical comparisons. Results: All the groups showed surface changes; titanium implants showed abrasion at the threads' flanks, and zirconia implants showed microfractures at the tip of the threads. Conclusion: Due to the insertion and removal of titanium and zirconia implants in dense bone, the flanks and tips of the implant threads will develop visible surface damage. Keywords: bone compression, implant insertion, titanium release, zirconia implants