In pursuit of optimizing dental implant design, this study aims to investigate the effects of square threads and variable thread dimensions to achieve optimal form. This research employed a combined methodology of finite element analysis (FEA) and numerical optimization to establish a mathematical model. Through design of experiments (DOE) and response surface methodology (RSM), an optimized shape for dental implants was achieved by meticulously studying the critical parameters. The simulated results were juxtaposed against the predicted values, all under ideal conditions. Within a one-factor RSM design for dental implants, subjected to a 450-newton vertical compressive load, the optimal thread depth-to-width ratio of 0.7 was found to minimize von Mises and shear stresses. Ultimately, the buttress thread configuration proved superior in minimizing both von Mises and shear stresses, compared to square threads, prompting the calculation of optimal thread parameters; a thread depth of 0.45 times the pitch, a width of 0.3 times the pitch, and an angle of 17 degrees. The consistent diameter of the implant enables the application of 4-mm abutments interchangeably.
The purpose of this research was to determine the impact of cooling temperatures on the reverse torque values generated during abutment placement in bone-level and tissue-level dental implants. A null hypothesis, pertaining to reverse torque values of abutment screws, predicted no distinction between cooled and uncooled implant abutments. Straumann bone-level and tissue-level implants (n=36 for each) were surgically placed into synthetic bone blocks, and further categorized into three groups (12 implants each), with each group distinguished by the abutment type utilized: titanium base, cementable abutment, and abutment for screw-retained restorations. Each abutment screw's torque was set to 35 Ncm. A dry ice rod was applied to the abutments near the implant-abutment junction for a minute in half the implants, before the abutment screw was loosened. The cooling process was omitted for the remaining implant-abutment pairs. Measurements of the maximum reverse torque values were accomplished using a digital torque meter. selleck inhibitor To obtain eighteen reverse torque values per group, the tightening and loosening procedure, including cooling for the test groups, was performed three times on each implant. Employing a two-way analysis of variance (ANOVA), the research investigated the consequences of cooling and abutment type on the measured values. Post hoc t-tests, set at a significance level of .05, were used to assess the differences between groups. Post hoc test p-values were adjusted for multiple comparisons using the Bonferroni-Holm procedure. In light of the findings, the null hypothesis was rejected. hepatitis b and c Reverse torque values for bone-level implants were found to be statistically significantly affected by the variables of cooling and abutment type (P = .004). Tissue-level implants were absent from the study, a statistically significant observation (P = .051). Cooling bone-level implants led to a considerable reduction in reverse torque values, declining from 2031 ± 255 Ncm to 1761 ± 249 Ncm. Significantly higher mean reverse torque values were found in bone-level implants (1896 ± 284 Ncm) in comparison to tissue-level implants (1613 ± 317 Ncm), representing a statistically significant difference (P < 0.001). Implant abutment cooling significantly diminished reverse torque values in bone-level implant procedures, potentially warranting its use as a pre-procedure treatment for removing impacted implant parts.
The study's intent is to examine the impact of preventive antibiotic use on sinus graft infection and/or dental implant failure rates in maxillary sinus elevation surgeries (primary outcome), and to determine the most suitable antibiotic protocol (secondary outcome). Between December 2006 and December 2021, the MEDLINE (PubMed), Web of Science, Scopus, LILACS, and OpenGrey databases underwent a comprehensive search. English-language comparative clinical trials, encompassing both prospective and retrospective designs, with a minimum of 50 patients, were included. The study's exclusion criteria included animal studies, systematic reviews and meta-analyses, narrative literature reviews, books, case reports, letters to the editor, and commentaries. The identified studies' assessment, data extraction, and bias risk evaluation were conducted independently by two reviewers. Should the need arise, authors were contacted. transrectal prostate biopsy Reporting the collected data involved the use of descriptive methods. Upon review, twelve studies conformed to the inclusion criteria. Analyzing antibiotic usage versus no usage in a single retrospective study, the researchers found no statistically significant difference in implant failure. However, crucial data concerning sinus infection rates were not included in their report. The sole randomized controlled trial that contrasted antibiotic administration schedules (the day of surgery versus seven additional postoperative days) did not discover any statistically significant difference in the rates of sinus infections between the comparative groups. Insufficient evidence exists to ascertain whether preventive antibiotics are beneficial or detrimental in sinus elevation procedures, or to determine if any particular protocol stands out.
This study aims to assess the precision (linear and angular deviation) of implant placement during computer-aided surgery, comparing different surgical strategies (fully guided, semi-guided, and freehand techniques) in combination with bone density (from D1 to D4) and the type of supportive surface (tooth-supported versus mucosa-supported). Using acrylic resin, a total of 32 mandible models, including 16 models that represented partial edentulism and another 16 that were completely edentulous, were produced. These models were calibrated individually to different bone densities, ranging from D1 to D4. Mguide software facilitated the placement of four implants in each acrylic resin mandible. A total of 128 implants were placed, divided into groups based on bone density (D1-D4, each with 32 implants), the degree of surgical guidance (80 fully guided [FG], 32 half-guided [HG], 16 freehand [F]), and support type (64 tooth-supported and 64 mucosa-supported). The analysis of linear, vertical, and angular discrepancies between the projected three-dimensional implant position and the measured actual position was achieved by calculating the linear and angular difference, employing preoperative and postoperative CBCT images. The effect was evaluated by applying linear regression models alongside parametric tests. In the neck, body, and apex regions, the technique employed was the key factor in determining the patterns of linear and angular discrepancies. Bone type, while also predictive, had a comparatively lesser influence. Both parameters, however, achieved statistical significance. Models that are entirely devoid of teeth are likely to display a greater degree of these discrepancies. Using regression models to compare FG and HG techniques, linear deviations show a buccolingual increase of 6302 meters at the neck, and a mesiodistal increase of 8367 meters at the apex. The accumulation of this increase is evident when contrasting the HG and F methodologies. Concerning bone density's impact, regression analyses revealed that linear deviations in the axial direction rise by 1326 meters to 1990 meters at the implant's apex in the buccolingual dimension with each decrease in bone density (D1 to D4). This in vitro study reveals that dentate models with high bone density and a fully guided surgical technique demonstrate the greatest predictability of implant placement.
To assess the response of hard and soft tissues, and the mechanical integrity of screw-retained layered zirconia crowns bonded to titanium nitride-coated titanium (TiN) CAD/CAM abutments supported by implants, at one and two-year follow-up periods. Forty-six patients received a total of 102 free-standing implant-supported crowns, each a layered zirconia restoration. Following bonding to their individual abutments in the dental laboratory, these were delivered as single-unit, screw-retained crowns. The baseline, one-year, and two-year follow-up data were compiled, including information on pocket probing depth, bleeding on probing, marginal bone levels, and mechanical complications. Four out of the 46 patients, each with a single implant, were not subject to follow-up. The analysis did not incorporate these patients. Despite disruptions caused by the global pandemic, soft tissue measurements were documented on 94 implants at one year and 86 at two years, among the 98 remaining implants. The average buccal/lingual pocket probing depth was 180/195mm at one year and 209/217mm at two years, respectively. At one and two years post-treatment, mean bleeding on probing measured 0.50 and 0.53, respectively, signifying a level of bleeding categorized as either absent or minimal according to the study's established criteria. Implant radiographic data was collected on 74 implants at one year and on 86 implants at two years. At the study's terminus, the ultimate bone level, referenced to the starting point, showed a +049 mm mesial shift and a +019 mm distal shift. A slight misfit of the crown margins in one unit (1%) indicated a mechanical complication. Porcelain fractures were documented in 16 units (16%). A preload reduction, less than 5 Ncm (under 20% of the initial preload), was found in 12 units (12%). Ceramic crowns, bonded to CAD/CAM screw-retained abutments with angled screw access, exhibited high levels of biological and mechanical stability, resulting in overall bone gain, favorable soft tissue health, and minimal mechanical complications limited to small porcelain fractures and negligible preload loss.
This study seeks to compare the marginal accuracy of soft-milled cobalt-chromium (Co-Cr) restorations to those produced by other construction methods or restorative materials for tooth/implant-supported restorations.