To evaluate occlusal splint type differences in patients with bruxism. Seventeen controls and 51 patients were divided into three subgroups, each assigned to use a different occlusal splint (hard, ...

Although the effects of different intraoral scanners, model scanners, and CAM units on the marginal and internal fitting of restorations have been investigated, the effects of CAD software in particular has not been evaluated. The marginal and internal fit of indirect restorations may vary according to the CAD software used, even when using the same intraoral scanner and milling machine. The purpose of this study was to evaluate the marginal and internal fit of milled full ceramic crowns designed with three different CAD systems. Eleven typodont maxillary first premolar teeth were prepared and scanned using a 3Shape TRIOS Intraoral Dental Scanner. The obtained STL scan data were exported and used to design a full crown using three different CAD systems (CEREC, KaVo, and Planmeca). An independent milling unit was used to manufacture the crowns for each group (n = 11). The marginal and internal fit were evaluated for each restoration using 2D and 3D micro-CT analysis. For 2D analysis, 18 measurements for each sample were made, covering the marginal (Marginal Gap Buccal (MG-A), Marginal Gap Palatinal (MG-B), Finish Line Buccal (FL-A), Finish Line Palatinal (FA-B)) and internal fit locations (Axial Wall Buccal (AW-A), Axial Wall Palatinal (AW-B), Lingual Cusp (LC), Buccal Cusp (BC), and Occlusal Central Fossa (OCF)). Statistical analyses were performed using Open Source R Statistical Software (α = 0.05) The results of Duncan's multiple range test showed that the values for the marginal measurement points MG-A, MG-B, FL-A, and FL-B in the Planmeca group were significantly higher than the values obtained in the CEREC and KaVo groups (p < 0.05). In AW1, values of the CEREC group were found to be higher than those of the KaVo and Planmeca groups (p < 0.05). CAD software showed an effect on the marginal fit values of crowns whereas no significant difference was observed in terms of the internal fit, except for a single measurement point made from the buccal direction.

: It has been considered that the preclinical education may be inadequate in the development of preparation skills of dental students. With technological developments, there is an increase in the use of computer-aided simulations in dental education. Virtual reality (VR) patient simulators promise practice in a realistic environment with detailed, frequent and objective feedback, but it remains unclear whether these features lead to better or faster skill acquisition. This study aims to investigate the impact of virtual reality simulations on students’ clinical preparation skills. In this study, tooth preparation data of 100 fourth-year students who practiced preparation with a virtual reality device and had real patient experience, as well as a group of 100 fifth-year students who had no prior virtual reality experience but had real patient experience, were transferred to the exocad® DentalCAD program, a CAD software, for the measurement of TOC (Total Occlusal Convergence) angles. The data obtained from these measurements were analyzed using the SPSS program. In addition to this study, 25 random individuals from both groups underwent preparation in a phantom model in order to make a comparison between different experience environments. Finally, a questionnaire was administered to the group trained in the simulator to evaluate the students’ perspective on this new training method. Independent sample T test and single sample analysis of variance (ANOVA), which are parametric test methods, and Tukey HSD, which is a post hoc test, were used in statistical analyses. With the t test, which is used to investigate whether there is a difference between two sample groups in terms of averages, we aimed to investigate the significance between class level and tooth cutting surface by using group statistics and descriptive analysis data of the preparations. With the ANOVA test, which is a statistical analysis method used to compare the averages between at least three groups, we looked at whether the preparations we made in 3 different experience environments produced a significant result according to the tooth cutting surface, and then we investigated which experience group was the source of the significance with the tukey test. In the descriptive statistical analysis, it was determined that the average preparation angles of the 4th-year students were lower than those of the 5th-year students. Accordingly, it is possible to say that grade levels affect all surface preparation results in a statistically significant way. In descriptive statistics regarding patient preparation experience, the averages of the preparation angles taken according to the tooth surfaces of the 4th and 5th Grades are; The averages of the mesial, distal and buccal surfaces are close to each other, but only on the palatal surfaces, there is a significant difference between the averages of the 4th Grade (12.46) and the current average of the 5th Grade (15.22). The results of the Independent Samples T-Test conducted in the context of grade levels and four surface areas, is examined, it is seen that there are statistically significant differences between grade levels and the preparation results of all surfaces (p < 0.05). According to the results of this study, students who used virtual reality simulators were more successful in terms of tooth preparation angles compared to students who did not use virtual reality simulators. This study demonstrated that the use of virtual reality simulators contributes to tooth prepartion skills.

While zirconia implants exhibit osseointegration comparable to that of titanium, concerns arise regarding low-temperature degradation and its potential impact on fracture strength. This study investigated the phase transformation and fracture characteristics of zirconia dental implants after aging through chewing simulation and subsequent static loading. The experimental setup involved 48 one-piece monobloc zirconia implants with diameters of 3.0 mm and 3.7 mm that had straight or angled abutments, with crown restorations, which were divided into six groups based on intraoral regions. The specimens underwent chewing simulation equal to five years of oral service, which was followed by static loading. Statistical analyses were performed for the data obtained from the tests. After dynamic and static loadings, the fractured samples were investigated by Raman spectroscopy to analyze the phase composition and micro-CT to evaluate fracture surfaces and volume changes. According to the results, narrow-diameter zirconia implants have low mechanical durability. The fracture levels, fracture patterns, total porosity, and implant fracture volume values varied according to the implant diameter and phase transformation grade. It was concluded that phase transformation initially guides the propagation of microcracks in zirconia implants, enhancing fracture toughness up to a specific threshold; however, beyond that point, it leads to destructive consequences.

Background and Objectives: CBCT images have been successfully used for CAD/CAM crown restorations; however, their use for ceramic inlay restorations remains unclear. This study aimed to evaluate the marginal and internal fit of CAD/CAM ceramic inlay restorations fabricated using intraoral scanner, model scanner, and CBCT data. Materials and Methods: Inlay preparations were performed on 11 mandibular molar typodont teeth. The teeth were scanned using an intraoral scanner, an extraoral scanner, and CBCT (0.075 mm voxel size). CBCT-generated DICOM data were converted to STL format with dedicated software. All scan data were transferred to CAD software, and a total of 33 restorations were designed. Feldspathic ceramic blocks were used for milling. Micro-CT was employed to measure marginal and internal gaps, with 60 measurement points taken from three cross-sections per sample. Data were analyzed using ANOVA and Bonferroni tests (p < 0.05). Results: CBCT exhibited greater marginal and internal gap dimensions (mean: 169.27 ± 38.64 μm), which were approximately 60–70 μm higher than those of the intraoral (97.00 ± 10.1 μm) and model scanner groups (109.67 ± 9.72 μm), exceeding clinically acceptable limits (≤120 μm) (p < 0.05). Intraoral and model scanners showed similar, clinically acceptable results. Conclusions: CBCT was less accurate for inlay restorations, likely due to their complex geometry. Nevertheless, fabrication was possible, and further research may improve its clinical applicability.