International Journal of Oral & Maxillofacial Implants最新文献

Purpose: To compare the biomechanical behaviors of different surgical options that are preferred for implant-supported fixed prosthetic rehabilitation of the atrophic edentulous maxilla. Materials and Methods: A 3D finite element analysis (FEA) model was generated from the computed tomography data of a patient with an atrophic edentulous maxilla. Four scenarios were created in the atrophic maxilla. In model 1, the maxilla was reconstructed with an onlay bone graft harvested from the anterior iliac crest, and sinus augmentation procedures were performed. Standard dental implants were placed in the lateral incisor, first premolar, and first molar regions on each side. In model 2, the anterior part of the atrophic maxilla was reconstructed with an onlay bone graft harvested from the mandibular ramus, and zygomatic implants were placed in the posterior part of the maxilla. In models 3 and 4, two-piece subperiosteal implants made of titanium and polyether ether ketone (PEEK) materials, respectively, were placed in the atrophic maxilla. All implants were loaded with 150-N and 50-N forces in vertical and lateral directions, respectively. Stress accumulation on bones, implants, abutments, and prosthetic frameworks was investigated. Results: The tensile stress in both cortical and trabecular bone was highest in the iliac bone grafting group under vertical loading. The compressive stress in both cortical and trabecular bone was the highest in the PEEK subperiosteal implant model, and the compressive stress value on the trabecular bone exceeded the strength of the trabecular bone. The highest von Mises stress in the implants was obtained in the iliac bone grafting group under vertical loading. The highest stress value in the abutments was detected for the titanium subperiosteal implant. The highest von Mises stress in the prosthetic framework was detected in the titanium subperiosteal implant group, under both vertical and lateral loading. Conclusion: Based on the stress accumulation results of the four different scenarios, it can be seen that there is no ideal treatment modality for the fixed implant-supported prosthetic rehabilitation of the atrophic edentulous maxilla. Various intraoperative and prosthetic modifications are suggested to decrease the risk of biomechanical complications during long-term follow-up.

Purpose: To assess the radiographic and histomorphometric outcomes of horizontally augmented maxillary alveolar ridges using solid nonperforated customized titanium barriers.

Materials and methods: This case series study included patients who received guided bone regeneration treatment in the anterior maxillary esthetic zone (eight patients, 18 dental implants) using patient-specific solid titanium barriers loaded with a mix of autogenous and xenogenic particulate bone grafts. A radiographic comparison between three time periods (immediately postoperative, 4 months, and 10 months) included software-aided calibration of the linear changes in the horizontal dimensions on CBCT cross-sectional cuts after being standardized. Bone core specimens were retrieved for histomorphometric analysis by the time of implant insertion.

Results: Wound healing was uneventful, except for two patients who showed soft tissue breakdown that did not affect the outcome. There was a statistically significant difference between the mean horizontal bone change at the different time intervals (P < .001), with a 79.6% ± 29.2% mean area of newly formed bone.

Conclusion: GBR using customized solid titanium barriers appears to be efficient and promising concerning the final horizontal bone gain and the quality of the augmented sites.

Purpose: To evaluate primary stability of a new dental implant design in low-density bone sites, compare it with another implant design previously studied in the same bone density, and explore possible correlations between primary stability parameters. Materials and Methods: The study was carried out on fresh humid bovine bone classified as type III. The test group consisted of 30 DS Prime Taper implants (PT), and the control group consisted of 30 Astra Tech EV implants (EV). All the implants were inserted according to the protocol provided by the manufacturer. After placement, variable torque work (VTW), peak insertion torque (pIT), and resonance frequency analysis (RFA) were recorded. Results: Mann-Whitney test showed that the mean VTW and pIT were significantly higher in the test group PT compared to the control group EV; furthermore, statistical analysis showed that the mean RFA was slightly higher in the control group EV but without reaching statistical significance. Pearson correlation analysis showed a very strong positive correlation between pIT and VTW values in both groups; furthermore, it showed a positive correlation between pIT and RFA values and between VTW and RFA values again in both groups. Conclusion: The results showed that the novel tapered implants were able to reach good primary stability in low-density bone sites and that this was superior to parallel-walled implants when measured with VTW and pIT. Moreover, a statistically significant correlation was found between the three methods used to measure implant primary stability.

Purpose: To evaluate the 15-year survival rate of zirconia (Y-TZP) implants with a roughened acid-etched surface in a retrospective post-market clinical follow-up (PMCF) study. Materials and Methods: One-piece ceramic implants (CeraRoot) with a roughened acid-etched surface (ICE) were used. Six different implant shapes/sizes were used in this study. Either a standard or flapless surgical approach was used for implant placement. Simultaneous bone augmentation or sinus elevation was performed when bone height or width was deficient. Definitive zirconia restorations were placed after 2 months or later if the Periotest value was > -3. The implants were followed up for up to 15 years. Results: A total of 1,828 implants were placed in 771 patients with a mean age of 51.18 years. The overall implant survival rate after 15 years of follow-up was 98.69%. Conclusion: From this long-term investigation, it can be concluded that CeraRoot ceramic implants showed a 15-year long-term clinical performance with a survival rate of 98.69% under the described protocol, without significant differences between the six implant shapes/sizes.

Purpose: To verify a novel method that improves the accuracy of static computer-aided implant surgery (sCAIS) through intraoperative measurement.

Materials and methods: Forty-seven patients were selected for this study, each with a missing tooth or a tooth that required extraction from the anterior area. The patients were divided into the intraoperative measuring guide (MG) and conventional guide (CG) groups. Following the preoperative implant planning, the surgical guides were designed and fabricated. In the MG group, the drill was guided by double-armed zirconia sleeves, and the axial direction of the drill was assessed using the indicator components. The implant was guided using a resin guide tube. In the CG group, the drills were guided using a metal sleeve and handles, and the implants were placed with the guidance of the metal sleeve only. The angular and linear deviations at the entry and apex between the planned and actual implant positions were measured after matching the preoperative and postoperative CBCT data. The independent-samples t test was used to compare the deviation between the MG and CG groups.

Results: The 3D deviations for the MG group at the entry and apex were 0.67 ± 0.44 mm and 0.93 ± 0.40 mm, respectively. The angular deviation was 2.27 ± 0.96 degrees. Statistical differences were found in the 3D deviation at the entry point and apical position between the MG and CG groups, yielding relatively smaller deviations in the MG group.

Conclusion: The use of an intraoperative measuring guide could improve the accuracy of implant placement in sCAIS.

Purpose: To evaluate the effect of maxillary sinus anatomy on sinus floor elevation (SFE) operations performed with the lateral window approach. Materials and Methods: CBCT and digital panoramic radiographs were evaluated before and at least 6 months after maxillary sinus floor elevation (SFE) operations performed in 33 maxillary sinus regions in 26 patients. Maxillary sinus volume, grafted volume (GV), sinus width (SW), residual bone height (RBH), and vertical graft resorption (VGR) were calculated. The effects of RBH and SW on GV and VGR were evaluated statistically. Results: The mean GV values in the maxillary sinuses classified as narrow, average, and wide were 2.60 ± 0.57, 3.44 ± 0.65, and 3.70 ± 0.64 cm³, respectively. The mean VGR was 2.12 ± 1.67 mm, and in the sites classified as narrow, average, and wide, the mean VGR values were 1.50 ± 0.79, 1.58 ± 1.28, and 3.46 ± 2.06 mm, respectively. A statistically significant difference in GV and VGR was found between the SW groups. The mean posterior maxillary RBH was 2.30 ± 1.05 mm, and 17 and 16 sinuses were classified as ≤ 2 and > 2 mm, respectively. There was no statistically significant difference in the effect of RBH on GV or VGR. Conclusion: Although posterior maxillary RBH did not affect new bone formation in the sinuses grafted only with hydroxyapatite-derived inorganic bovine bone, with increasing SW, the GV decreased and the VGR increased.

Time-to-event (survival) analysis is an integral tool in the wheelhouse of the dental researcher. While there are many references available for the study of time-to-event analysis, they tend to be written for audiences trained in statistical methodology. Moreover, the canonical examples offered by most time-to-event analysis references are focused on outcomes that do not translate directly to dentistry. This article provides a tutorial of time-to-event analysis for the specific context of dental research. Our tutorial assumes no statistical training or computing experience. Using real data from a dental study as our extended example, we explain foundational concepts, including median survival, Nth-year survival, the log-rank test, and the Cox model.

Purpose: To systematically analyze the outcomes of immediate implant placement (IIP) with bone grafting in the esthetic area. Materials and Methods: PubMed, Embase, and Cochrane CENTRAL were searched. Prospective studies reporting midfacial soft tissue recession (primary outcome) of single-tooth IIP with bone grafting in the esthetic area were included. Risks of bias were assessed. Meta-analysis, sensitivity analysis, and meta-regression were undertaken. Results: A total of 13 studies and 421 patients were included, with a follow-up length of 1 to 10 years in function. The weighted mean (95% CI) of midfacial soft tissue recession was 0.33 (0.21, 0.46) mm and 0.54 (0.16, 0.93) mm after 1 year and 5 years in function. Meta-regression indicated that after 1 year in function, there was 0.33 mm less midfacial soft tissue recession with soft tissue grafting (P = .021), while there was 0.58 mm more soft tissue recession (P = .007) in defect extraction sockets. Implant survival was 97.8%, and all failures were early failures. Peri-implant soft and hard tissue stability, peri-implant health, esthetic outcomes, and patient satisfaction were predictable within the follow-up period. Conclusion: Midfacial soft tissue recession showed an ongoing status in IIP with bone grafting in the esthetic area within 5 years in function. For extraction sockets with a thin gingival biotype or deficient buccal bone wall, soft tissue grafting was recommended.

Purpose: To determine whether a less invasive window repositioning technique could provide a feasible, safe, and reliable lateral sinus augmentation.

Materials and methods: The less-invasive window repositioning technique using a piezoelectric saw was performed on adult patient candidates for lateral sinus floor elevation. The augmented bone height (primary outcome variable), bone length, and posthealing outcome variables were evaluated to determine the augmentation adequacy, safety, and reliability of this technique overall and in one- and two-implant groups with different window dimensions. Data were analyzed using descriptive statistics, chi-square test, and Pearson correlation analysis. P < .05 was considered significant.

Results: A total of 50 consecutive sinus floor elevations with simultaneous placement of 66 implants (one-implant: 34, two-implant: 16) were performed on 44 subjects (72% men) with a mean age of 46.7 ± 10.3 years and followed for a mean of 13.28 ± 3.5 months. The overall, one-implant, and two-implant group mean window sizes were 31.38 ± 6.78 mm², 28.38 ± 4.2 mm², and 37.75 ± 6.88 mm², respectively. The mean overall augmented bone height and length were 12.3 ± 1.04 mm and 19.67 ± 2.01 mm, respectively. The mean window size was significantly smaller in the one-implant group versus the two-implant group (P < .001). However, there was no correlation between window size and augmented bone height (r = -0.9, P = .54) and length (r = 0.05, P = .68). The posthealing outcome variables showed perfect window integration without soft tissue ingrowth. Six sinus perforations (12%) during membrane elevation that were not related to window osteotomy were observed and were appropriately managed.

Conclusion: The less-invasive window repositioning technique is feasible, safe, and reliable for appropriate sinus augmentation in height and length. The reduction of window dimension does not influence the feasibility, augmentation adequacy, and surgical safety and does not increase surgical risks or membrane perforation. The repositioned window showed proper integration. Also, sinus floor elevation through this technique is an experience-based surgery that requires delicate instruments.

Purpose: Zygomatic implants (ZIs) have been considered a reliable alternative treatment for patients with maxillary atrophy and/or maxillary defects. The use of a navigation system for assisting ZI placement could be a reliable approach for enhancing accuracy and safety. The purpose of this in vitro study was to evaluate the accuracy of a new dynamic surgical navigation system with its minimally invasive registration guide for quad zygomatic implant placement in comparison with a gold standard navigation approach. Materials and Methods: A total of 40 zygomatic implants were placed in 10 3D-printed models based on the CBCT scans of edentulous patients. For registration, a surgical registration guide with a quick response plate was used for the test group, and five hemispheric cavities as registered miniscrews in the intraoral area were used for the control group. In each model, a split-mouth approach was employed (two ZIs in bilateral zygomata) to test both systems. After ZI placement, a CBCT scan was performed and merged with pre-interventional planning. The deviations between planned and placed implants were calculated as offset basis, offset apical, and angular deviation and compared between the systems. Results: The offset basis, offset apical, and angular deviation were 1.43 ± 0.55 mm, 1.81 ± 0.68 mm, and 2.32 ± 1.59 degrees in the test group, respectively. For the control group, values of 1.48 ± 0.57 mm, 1.76 ± 0.62 mm, and 2.57 ± 1.51 degrees were measured without significant differences between groups (all P < .05). The accuracy of ZI positions (anterior and posterior) were measured without significant differences between groups. Conclusion: Two navigation systems with different registration techniques seem to achieve comparable acceptable accuracy for dynamic navigation of zygomatic implant placement. With the test group system, additional pre-interventional radiologic imaging and invasive fiducial marker insertion could be avoided.