International Journal of Oral & Maxillofacial Implants最新文献

Purpose: To propose and evaluate a novel method for achieving a favorable bone-to-implant contact (BIC) area for zygomatic implants (ZIs). Materials and Methods: Patients who needed ZIs to restore a severely atrophied maxilla were recruited. In preoperative virtual planning, an algorithm was utilized to find the ZI trajectory that would achieve the largest BIC area with a predefined entry point on the alveolar ridge. The surgery was conducted according to the preoperative plan with the assistance of real-time navigation. Area BIC (A-BIC), linear BIC (L-BIC), distance from implant to infraorbital margin (DIO), distance from implant to infratemporal fossa (DIT), implant exit section, and deviation of the real-time navigated surgery were measured and compared between the preoperative plan and the placed ZIs. The patients were followed up for 6 months. Results: Overall, 11 patients with 21 ZIs were included. The A-BICs and L-BICs were significantly higher in the preoperative plan than in the placed implants (P < .05). Meanwhile, there were no significant differences in DIO or DIT. The planned-placed deviation was 2.31 ± 1.26 mm for the entry, 3.41 ± 1.77 mm for the exit, and 3.06 ± 1.68 degrees for the angle. All ZIs survived to the 6-month follow-up. Conclusion: This novel method can virtually calculate the trajectory of ZIs and transfer the preoperative plan to surgery to acquire a favorable BIC area. The actual positions of placed ZIs were slightly deviated from the ideal due to navigation errors.

Purpose: To compare the matrix metalloproteinase-8 (MMP-8) levels in the peri-miniscrew implant crevicular fluid (PMCF) of immediate-loaded and delayed-loaded miniscrew implants at different time intervals. Materials and Methods: Titanium orthodontic miniscrews were placed bilaterally in the attached gingiva of 15 patients between the maxillary second premolar and maxillary first molar for en masse retraction. This split-mouth study was designed to have an immediate-loaded miniscrew on one side and a delayed-loaded miniscrew on the other side that was loaded 8 days after miniscrew placement. PMCF was collected from the mesiobuccal aspects of the immediate-loaded implants at 24 hours, 8 days, and 28 days after loading, and from the delayed-loaded miniscrew implants at 24 hours and 8 days before loading and 24 hours and 28 days after loading. An enzyme-linked immunosorbent assay kit was used to assess MMP-8 levels in the PMCF samples. Unpaired t test, ANOVA F-test, and Tukey post hoc test were used to evaluate data at the P < .05 level. Results: Although there were slight alterations in the MMP-8 levels in the PMCF over time, there was no statistically significant difference in the MMP-8 levels between groups. There was a statistically significant decrease in the levels of MMP-8 between 24 hours after miniscrew placement and 28 days after loading on the delayed-loaded side (P < .05). Conclusion: The MMP-8 levels did not vary much between immediate-loaded and delayed-loaded miniscrew implants as a result of the force application. However, there was no significant difference between immediate loading and delayed loading in terms of biologic response to mechanical stress. The increase in MMP-8 levels after 24 hours post-miniscrew insertion, as well as the subsequent gradual reduction over the course of the study period in both immediate and delayed groups after loading, is probably due to the bone adapting to stimuli.

Purpose: To evaluate the effectiveness of extra-short implants compared to standard-length implants in graft regions at different longitudinal follow-up times. Materials and Methods: A systematic review was performed, following PRISMA criteria. LILACS, MEDLINE/PubMed, Cochrane Library, and Embase databases, including gray literature and manual searches, were conducted without language or date restrictions. Study selection, risk of bias (Rob 2.0), quality of evidence (GRADE), and data collection were performed by two independent reviewers. Disagreements were resolved by a third reviewer. Data were combined using the random-effects model. Results: A total of 1,383 publications were identified, including 11 publications from 4 randomized clinical trials that evaluated 567 implants (276 extra-short and 291 regular implants with graft) in 186 patients. The meta-analysis showed that losses (risk ratio [RR]: 1.24; 95% CI: 0.53 to 2.89; P = .62; I²: 0%) and prosthetic complications (RR: 0.89; 95% CI: 0.31 to 2.59; P = .83; I²: 0%) were similar in both groups. Biologic complications were significantly higher in regular implants with graft (RR: 0.48; CI: 0.29 to 0.77; P = .003; I²: 18%), which also had lower peri-implant bone stability in the mandible at the 12-month follow-up (mean deviation [MD]: -0.25; CI: -0.36 to 0.15; P < .00001; I² = 0%). Conclusion: Extra-short implants showed similar effictiveness compared to standard-length implants placed in grafted regions at different longitudinal follow-up times and present reduced biologic complications, shorter treatment times, and greater peri-implant bone crest stability.

Purpose: To compare the effects of regular implant drills to osseodensifying drills used in clockwise and counterclockwise motions on bone dimension change and primary implant stability. Materials and Methods: A total of 40 bone models were made (20 × 15 × 4 mm) from porcine tibia to represent implants placed in soft bone. Implant osteotomies were prepared in the bone models using one of the following techniques: (1) regular implant drills in a clockwise direction (group A), (2) regular implant drills in a counterclockwise direction (group B), (3) osseodensifying drills in a clockwise direction (group C), and (4) osseodensifying drills in a counterclockwise direction (group D). Bone-level tapered titanium alloy implants (4.1 × 10 mm) were placed following osteotomy creation. The implant stability quotient (ISQ) was measured after implant placement. Each bone model was scanned with an optical scanner to convert to Standard Tessellation Language (STL) files before and after the osteotomy creation. Presurgical and postsurgical STL files were superimposed, and the dimensional changes were measured at 1, 3, and 7 mm from the crestal bone. Histomorphometric analysis was done, and bone-to-implant contact percentage (BIC%) was calculated. Results: There were no significant differences in ISQ values (P = .239) between any of the groups. Histomorphometric analysis showed implants in group D had significantly higher BIC% than groups A (P = .020) and B (P = .009). The amount of bone expansion decreased with distance from the crest (P < .001). Groups B (P = .039) and D (P = .001) showed significant expansions at all levels compared with group A. No other statistically significant differences in dimensional change were found between groups. Conclusion: Both regular and osseodensification burs used in a counterclockwise motion contribute to expansion of bone dimension compared to conventional drilling methods.

Purpose: To evaluate the implant survival and the prevalence of biologic and mechanical complications in edentulous patients restored with complete-arch implant-supported fixed dental prostheses (IFDPs). Materials and Methods: Patients restored with complete-arch screw-retained IFDPs between January 2012 and December 2019 with a minimum 2-year follow-up were included. Outcome measures were cumulative survival rate (CSR) for implants and prostheses, biologic complications, and mechanical complications. A generalized estimating equation model was used to estimate potential risk factors for mechanical complications. Patient satisfaction was investigated using a standardized questionnaire. Results: A total of 44 prostheses supported by 268 implants in 30 patients were included for a mean duration of 4.8 years (range: 2 to 9 years). Eighteen of the prostheses were zirconia-ceramic (group ZC), and 26 were titanium-ceramic (group TC). The CSR for the implants and IFDPs was 99.3% (95% CI: 98.2% to 100.3%) and 92.5% (95% CI: 84.2% to 100.8%), respectively. The most common biologic complication was peri-implant mucositis (4.5%), followed by peri-implantitis (3.0%). The most common mechanical complication was ceramic chipping (45.5%), followed by crown debonding (13.6%) and framework fracture (4.5%). There was no significant difference in the prevalence of complications between groups TC and ZC (P > .050). The presence of cantilever (OR = 5.54, P = .048) and maxillary arch (OR = 5.94, P = .041) were significantly associated with mechanical complications. Patient satisfaction scores were generally high, but some continued to be bothered by speech problems (13.6%). Conclusion: Complete-arch IFDPs presented reliable clinical outcomes for edentulous patients with a high implant survival rate and a high level of patient satisfaction. However, a high incidence of mechanical complications occurred in the long term.

Purpose: To evaluate the accuracy and clinical usability of an identification model using ensemble deep learning for 130 dental implant types. Materials and Methods: A total of 28,112 panoramic radiographs were obtained from 30 domestic and foreign dental clinics. From these panoramic radiographs, 45,909 implant fixture images were extracted and labeled based on electronic medical records. Dental implants were classified into 130 types according to the manufacturer, the manufacturer's implant system, and the diameter and length of the implant fixture. Regions of interest were manually cropped, and data augmentation was performed. According to the minimum number of images collected per implant type, the datasets were classified into three sets: an overall total of 130 and two subsets that consisted of 79 and 58 types. EfficientNet and Res2Next algorithms were used for image classification in deep learning. After testing the performance of the two models, the ensemble learning technique was applied to improve accuracy. The top-1 accuracy, top-5 accuracy, precision, recall, and F1 scores were calculated according to algorithms and datasets. Results: For the 130 types, the top-1 accuracy, top-5 accuracy, precision, recall, and F1 scores were 75.27, 95.02, 78.84, 75.27, and 74.89, respectively. In all cases, the ensemble model performed better than EfficientNet and Res2Next. When using the ensemble model, the accuracy increased as the number of types decreased. Conclusion: The ensemble deep learning model for the identification of 130 types of dental implants showed higher accuracy than the existing algorithms. To further improve the performance and clinical usability of the model, images with higher quality and fine-tuned algorithms optimized for implant identification are required.

Purpose: To examine how the accuracy (linear and angular deviation) of implants placed using computer-guided surgery varies in relation to the type of surgical technique (fully guided, half-guided, vs freehand implant placement), bone density (type D1 to D4 bone), and type of support surface (tooth- vs mucosa-supported). Materials and Methods: A total of 32 mandible models were produced (16 partially edentulous and 16 edentulous) using acrylic resin, each calibrated to a different bone density (D1 to D4). Four implants planned using Mguide software were placed in each acrylic resin mandible. A total of 128 implants were placed, distributed according to bone density (D1 to D4, n = 32), the degree of intervention in the surgery (fully guided [FG] = 80, half-guided [HG] = 32, and freehand surgery [F] = 16), and the type of support surface (tooth-supported: n = 64 and mucosa-supported: n = 64). To determine the linear, vertical, and angular deviations between the planned three-dimensional position and the actual position of the implants, the linear and angular difference between them was calculated, with the analysis performed through preoperative and postoperative CBCT scans. The effect was analyzed using parametric tests and linear regression models. Results: All parameters of linear and angular discrepancy in the various regions analyzed (neck, body, and apex) were primarily influenced by the technique and, to a lesser extent, by the bone type, although both variables were predictive and highly significant. These discrepancies tend to increase in completely edentulous models. The regression models show that linear deviations increase by between 630.2 μm at neck level in the buccolingual direction and 836.7 μm at apex level in the mesiodistal direction when comparing the FG and HG techniques. This increase is accumulative when comparing the HG and F techniques. Regarding the effect of bone density, the regression models found that linear discrepancies increase by between 132.6 μm in the axial direction and 199.0 μm at the apex of the implant in the buccolingual direction with each reduction in bone density (D1 to D4). Conclusion: According to this in vitro study, the highest implant placement predictability is found among dentate models with high bone density and a fully guided surgical technique.

Purpose: To evaluate the marginal accuracy of soft-milled cobalt-chromium (Co-Cr) compared to other construction methods/restorative materials in tooth/implant-supported restorations. Materials and Methods: PICO questions were defined, and a systematic search was conducted in six electronic databases. Titles and abstracts were collected and screened by two independent reviewers. After removing duplicate articles, the full texts of relevant articles were gathered, and the required information and data were extracted. Risk of bias was assessed and meta-analyses of the collected data were conducted using STATA software version 16. Results: A total of 1,914 experimental and clinical articles were reviewed, and 18 studies were selected for qualitative analysis. The 16 studies that were included in the meta-analysis showed no significant marginal gap differences between soft-milled Co-Cr and the following methods/materials: hard-milled Co-Cr (I² = 92.9%, P = .86), casting wax (I² = 90.9%, P = .42), laser-sintered Co-Cr (I² = 93.3%, P = .46), and zirconia (I² = 0.00%, P = .47). However, a significantly higher marginal accuracy of soft-milled Co-Cr was observed when compared to milled-wax casting (I² = 93.1%, P < .001). Conclusion: The marginal gap of soft-milled Co-Cr restorations is within the acceptable clinical range and provides an accuracy similar to other available methods/materials for both the prepared implant abutment and tooth.

Purpose: To develop, analyze, and optimize a dental implant by considering square threads and varying the thread dimensions to obtain an optimal shape. Materials and Methods: For this study, finite element analysis (FEA) and numerical optimization method were integrated to develop a mathematical model. The critical parameters of dental implants were studied, and an optimized shape was obtained using response surface method (RSM) and design of experiment (DOE). The simulated results were then compared to the predicted values under optimal conditions. Results: Using the one-factor RSM design model for the dental implant and a vertical compressive load of 450 N for testing, the optimal depth to width ratio for the thread was 0.7 in order to achieve the minimum von Mises and shear stress. Conclusion: The buttress thread was found to be the optimal shape for achieving the lowest von Mises and shear stress compared to square threads, and the thread parameters were calculated accordingly, with a thread depth 0.45 times the pitch, a width 0.3 times the pitch, and a thread angle of 17 degrees. Also, due to the constant diameter of the implant, common 4-mm diameter abutments can be used interchangeably.

Purpose: To compare the osteoblastic activity around dental implants placed via adaptive osteotomy and osseodensification techniques using bone scintigraphy in human subjects. Materials and Methods: A single-blinded, split-mouth design was conducted on two sites in each of the 10 subjects, with the adaptive osteotomy (n = 10) and osseodensification (n = 10) techniques for implant placement performed on either side of the D3-type bone in the posterior mandible. All participants were subjected to a multiphase bone scintigraphy test on the 15th, 45th, and 90th days after implant placement to evaluate the osteoblastic activity. Results: The mean values obtained on the 15th, 45th, and 90th days in the adaptive osteotomy group were 51.14% ± 3.93%, 51.40% ± 3.41%, and 50.73% ± 1.51%, respectively, while the osseodensification group values were 48.88% ± 3.94%, 48.78% ± 3.38%, and 49.29% ± 1.56%, respectively. The intragroup and intergroup analyses revealed no significant difference between the mean values of the adaptive osteotomy and osseodensification groups on the tested days (P > .05). Conclusions: Osseodensification and adaptive osteotomy techniques improved primary stability of D3-type bone and accelerated the osteoblastic activity after implant placement, with no superiority of one method over the other.