A method is described for the cost-effective tracking of mandibular movements using an open-source software program (Blender v. 4.3; Blender Foundation) in combination with video recordings and intraoral scans. Semispherical resin markers serve as reference points, synchronizing virtual cast movements from intraoral scanning. These data can be integrated into a CAD software program with facial scanning and cone beam computed tomography.
Statement of problem: Despite the widespread success of dental implants, crestal bone loss (CBL) remains a significant challenge, compromising long-term stability and esthetics.
Purpose: The purpose of this systematic review and meta-analysis was to evaluate the effectiveness of platform switching in reducing CBL compared with conventional implant designs.
Material and methods: This systematic review and meta-analysis used primary and alternate search terms (identified through MeSH searching) to retrieve relevant studies published up to April 2024 from global databases, including PubMed (Medline), Scopus, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov. The random-effects model was applied to calculate the weighted mean differences (WMD) and 95% confidence interval (95% CI) of the CBL for the meta-analysis. The quality of the included studies was assessed with the Cochrane Risk of Bias Tool (RoB 2).
Results: The meta-analysis revealed that the platform-switching technique significantly reduced CBL compared with conventional implant designs. On average, implants with platform switching showed a 0.22-mm reduction in CBL (WMD=-0.22; 95% CI=-0.39, -0.05; I²=58.18%; Pheterogeneity=.069). Subgroup analyses indicated that this reduction was most pronounced for single implants (WMD=-0.42; 95% CI=-0.49, -0.35) and at the posterior mandible site (WMD=-0.48; 95% CI=-1.11, -0.15). Conventional loading restorations also showed a greater decrease in CBL compared with immediate and functional loading (WMD=-0.33 versus -0.06 and -0.08). Additionally, longer follow-up periods beyond 36 months resulted in a more substantial reduction in CBL (WMD=-0.50; 95% CI=-0.55, -0.45).
Conclusions: These findings support the use of platform switching as a strategy to enhance implant stability and long-term outcomes, highlighting its potential for improving clinical practices in implant dentistry. Further research is recommended to confirm these benefits and explore the underlying mechanisms.
Statement of problem: Intraoral scanning of complete arch implant-supported prosthesis is still not predictable in all scenarios. Photogrammetry was introduced to overcome physical and anatomic limitations. The use of a new intraoral scanner combined with photogrammetry technology in a simplified workflow may improve the ease of fabrication and accuracy of complete arch implant-supported prostheses.
Purpose: The purpose of this clinical study was to evaluate the degree of trueness of a conventional intraoral scanner (IOS) and an intraoral photogrammetry scanner (IPS) for complete arch implant-supported prostheses.
Material and methods: Participants who had received 4 implants in an edentulous arch for an implant-supported complete arch fixed dental prosthesis were recruited. Three recordings were obtained for each participant: IOS, IPS (tests), and a conventional splinted open-tray impression (reference). Three-dimensional (ΔEUC), and angular deviations (ΔANGLE) for both groups (IOS and IPS) were evaluated and compared with the reference scan. Potential effects (correlation) of the impression device (IOS and SPG) and type of arch (maxilla and mandible) were evaluated. A paired t test was used to evaluate both the angular and 3-dimensional deviation for each implant position. A point-biserial correlation was conducted to assess the relationship between jaw type and angular and ΔEUC deviations in the 2 groups.
Results: Thirteen edentulous arches (9 maxillae, 4 mandibles) in 11 individuals were rehabilitated with a monolithic zirconia screw-retained prosthesis supported by 4 implants, totaling 52 implants. Conventional intraoral scanners (IOS) and intraoral photogrammetry scanners (IPS) were used to scan 104 implant positions, which were then compared with the corresponding reference scans. (mean ΔEUC IOS 59.8 µm, IPS 30.7 µm; mean ΔANGLE IOS 1.4 degrees, IPS 0.78 degrees). A paired t test revealed statistical significance in favor of IPS in terms of both Euclidian and angular deviation (P<.001). In the IOS group, angular deviation had a positive statistically significant correlation with the type of arch (rpb=0.34, n=52, P=.013).
Conclusions: The IPS significantly improved the ease and accuracy of recording complete arch implant-supported prostheses.
Statement of problem: Bruxism has been characterized by factors that include clenching or grinding leading to excessive and repeated forces on implant-supported prostheses, leading to multiple complications. Several systematic reviews have been published on this subject; however, umbrella reviews are lacking.
Purpose: The purpose of this umbrella review was to assess the methods and quality of systematic reviews examining the relationship between implant-supported prosthesis failure and bruxism.
Material and methods: An electronic search into PubMed/MEDLINE and Scopus databases was conducted for articles published between January 1994 and April 2025. The reference lists were also searched. The eligibility criteria included systematic reviews that encompassed the relationship between bruxism and the failure of implant-supported prostheses. Quality analysis of the reviews was performed based on AMSTAR guidelines and the Glenny et al checklist. The review was registered in PROSPERO with the identification code CRD420251032758.
Results: The initial search resulted in 2395 articles, and 50 full-text articles remained for evaluation. Eight systematic reviews met the eligibility criteria and were included in this study, 5 of which included meta-analysis. The results revealed heterogeneity among the studies. Two systematic reviews exhibited perfect AMSTAR scores, whereas one systematic review showed a perfect Glenny et al score. The more recent systematic reviews revealed bruxism to be an important risk factor in the failure of implant-supported prostheses. Meta-analyses revealed a higher risk of failure in bruxers compared to non-bruxers. One systematic review reported an odds ratio of 4.68, indicating that failure was 4.68 times more likely in bruxers.
Conclusions: Bruxism plays an important role in the failure of implant-supported prostheses.
Statement of problem: The impact of different finishing protocols following preparation for indirect restorations on surface roughness, smear layer, and bond strength remains unclear, with potential implications for clinical longevity.
Purpose: The purpose of this in vitro study was to evaluate the effect of different dentin finishing protocols on surface (roughness and morphology), smear layer thickness, and bond strength to a resin-matrix glass-ceramic.
Material and methods: Unused preparation instruments were characterized under scanning electron microscopy (SEM), and 144 human third molars were prepared and divided into groups: control (medium grit diamond rotary instruments, no finishing [CT]), fine/superfine diamond rotary instruments [FB], fine/superfine tungsten carbide burs [CB], fine/superfine ultrasonic diamond tips [UT], SiC/Al₂O₃ mounted stones [MS], fine/superfine sintered diamond rotary instruments [SB], Al₂O₃ airborne-particle abrasion [AO], and resin coating [RC]. Surface roughness and morphology were analyzed using laser scanning confocal microscopy and SEM. Smear layer thickness was assessed using SEM combined with the ImageJ software program, and bond strength was evaluated using microtensile testing. One-way analysis of variance (ANOVA) and post hoc tests were used for statistical analysis, followed by Pearson correlation. Failure modes were analyzed using the chi-squared test (α=.05).
Results: Significant differences in surface roughness, smear layer thickness, and bond strength were observed across the groups (P<.001). All finishing protocols resulted in lower surface roughness and higher bond strength compared with the control. RC achieved the highest bond strength, followed by MS. A very weak correlation was found between surface roughness, smear layer thickness, and bond strength.
Conclusions: Finishing protocols affect dentin roughness, smear layer, and bond strength after tooth preparation. Resin coating and fine and superfine mounted SiC and Al₂O₃ stones improved adhesion and may enhance outcomes for indirect restorations.
Statement of problem: Dental caries, a widespread chronic disease, has been difficult to detect, especially in posterior proximal regions. Conventional diagnostic methods, such as visual inspection and radiography, are subjective and inconsistent across clinicians.
Purpose: The purpose of this study was to develop and evaluate a deep learning-based method for automated detection and segmentation of dental caries in panoramic radiographs.
Material and methods: A deep learning pipeline combining Faster Regions based Convolutional Neural Networks (R-CNN) and U-Net architectures was developed. The Faster R-CNN model was used to detect tooth regions, and the U-Net model segmented carious areas within these regions. Performance differences against comparative models were evaluated for statistical significance using paired t tests (α=.05).
Results: The proposed method achieved an intersection over union of 0.6075, a dice coefficient of 0.7429, a recall of 0.7309, and a precision of 0.7881. This performance represented an improvement in intersection over union, dice coefficient, and recall over conventional segmentation models, with the difference being statistically significant (P<.05).
Conclusions: The results indicated that the proposed deep learning method was effective in detecting and segmenting dental caries in panoramic radiographs and showed potential for improving diagnostic accuracy.
Statement of problem: Creating precise 3D virtual head models for patients with complete maxillary edentulism remains challenging owing to the lack of natural landmarks and limitations of current image-matching technologies.
Purpose: The purpose of this study was to evaluate the positional accuracy of intraoral scan alignment to structured light-based facial scans using varying sizes and positions of occlusal rim markers under maxillary edentulous conditions.
Material and methods: Radiopaque artificial markers of 3 sizes (2, 4, and 6 mm) were made and attached to the maxillary occlusal rim of a completely edentulous patient at different positions (midline-canine [MC], midline [M], canine [C]). Facial scans were obtained of the patient by using a structured light facial scanner under 9 experimental conditions (size-location: 2MC, 2M, 2C, 4 MC, 4M, 4C, 6MC, 6M, and 6C; 5 scans under each condition). Intraoral scans were aligned to the facial scans using stepwise images matching the occlusal rim scan casts. The alignment accuracy was evaluated by comparing the intraoral scan with a reference position established using cone beam computed tomography data. Measured variables included anterior and posterior linear deviations and angular deviation of the arch plane. Statistical analysis was conducted using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni correction (α=.05).
Results: The 4-mm and 6-mm marker groups exhibited significantly lower deviation in image registration than the groups without markers and those with 2-mm markers (P<.001). Regarding the marker position, the midline-canine group exhibited the lowest deviation value, followed by the midline and canine groups. Markers positioned in the midline exhibited less deformation compared with those in the canine region.
Conclusions: Occlusal rim markers can be used to align intraoral and facial scans in patients with complete maxillary edentulism when structured light face scanning is included. Markers with a clearly recognizable size in facial scans are less prone to deformation in the facial midline area.
Digital scanning techniques have offered clinicians a faster and more patient-friendly treatment workflow. However, the fabrication of a definitive prosthesis often necessitates a physical cast to ensure precise verification. While 3-dimensionally (3D) printed casts provide excellent accuracy, introducing laboratory analogs to these casts can result in subtle discrepancies that compromise the definitive prosthesis. This underscores the continued relevance of traditional impression methods, which remain the standard for achieving accuracy in complex clinical scenarios. This article presents a tray-less impression technique as an innovative hybrid approach, merging the precision of traditional impressions with modern digital efficiency. By using a 3D printed verification device, such as S-Plates, and a combination of polyvinyl siloxane (PVS) putty and light-body impression materials, this method delivers a straightforward, yet reliable, workflow. It minimizes procedural challenges while maintaining the accuracy required for complete arch, fixed implant-supported restorations.
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