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Few investigations have evaluated the 3-dimensional (3D) accuracy of digital implant scans. The aim of this study was to evaluate the performance of 10 intraoral scanners (IOSs) (CEREC Omnicam, CEREC Primescan, CS 3600, DWIO, i500, iTero Element, PlanScan, Trios 2, Trios 3, and True Definition) in obtaining the accurate positions of 6 cylinders simulating implant scan bodies. Digital scans of each IOS were compared with the reference dataset obtained by means of a coordinate measuring machine. Deviation from the actual positions of the 6 cylinders along the XYZ axes and the overall 3D deviation of the digital scan were calculated. The type of IOSs and position of simulated cylindrical scan bodies affected the magnitude and direction of deviations on trueness. The lowest amount of deviation was found at the cylinder next to the reference origin, while the highest deviation was evident at the contralateral side for all IOSs ( p  < 0.001). Among the tested IOSs, the CEREC Primescan and Trios 3 had the highest trueness followed by i500, Trios 2, and iTero Element, albeit not statistically significant ( p  > 0.05), and the DWIO and PlasScan had the lowest trueness in partially edentulous mandible digital implant scans ( p  < 0.001).

We aimed to evaluate the risk of coronary heart disease (CHD) according to dental caries status in middle-aged patients using a population-based cohort database containing medical/dental claims, health examination, and death records in the Republic of Korea. A total of 234,597 patients were identified in the database who were without history of cardiovascular disease, including 104,638 patients without dental caries, 41,696 with incipient/moderate stage dental caries, and 88,262 advanced/severe dental caries. We used Cox proportional hazards model adjusted for sociodemographic, lifestyle, and medical characteristics to compute hazard ratio (HR) and 95% confidence intervals (95% CI) for CHD according to severity of dental caries. During 1,491,190 person-years of follow-up, there were a total of 6,015 CHD events. After adjustment for potential confounders, patients in the highest quartile of outpatient visits for advanced/severe stage dental caries was associated with an increase in CHD risk (HR = 1.13; 95% CI: 1.04–1.22) as compared with patients without dental caries. When the analysis was restricted to the patients with advanced/severe dental caries, dose-response relationship between number of outpatient visits for dental caries and risk of CHD was observed ( P trend : <0.001). Prevention and control of dental caries might be worth promoting in clinical practice to prevent CHD.

Aim. The objective of this in vitro study was to evaluate the bond strength of universal adhesive systems in self-etch and etch-and-rinse modes at the repair interface between aged and new composite resins. Materials and Methods. Composite resin (Filtek Z250) was thermocycled to represent aged composite resin to be repaired. New composite resin was placed over the aged substrate after surface conditioning: NC (negative control, no surface treatment), A (adhesive only), SBM (Scotchbond Multi-Purpose in etch-and-rinse mode), CSE (Clearfil SE Bond in self-etch mode), SBU (Single Bond Universal), ABU (All Bond Universal), and TBU (Tetric N-Bond Universal). Universal adhesives (SBU, ABU, and TBU) were applied both in etch-and-rinse and self-etch modes. 1 mm×1 mm×8 mm beams were sectioned, and microtensile bond strength was measured after 24 hours of water storage and 10,000 thermocycling processes (n=20/group). The fracture surfaces were observed with a scanning electron microscope to evaluate the failure pattern. Results. The repair bond strength between the old and new composite resins was material-dependent. Universal adhesives significantly improved the repair bond strength (p<0.05), while no significant difference was observed between the etch modes (self-etch or etch-and-rinse) for each universal adhesive (p>0.05). Thermocycling significantly reduced the bond strength in all groups (p<0.05). Conclusion. Universal adhesives in both etch-and-rinse and self-etch modes outperformed the conventional 3-step etch-and-rinse and 2-step self-etch adhesive systems in terms of resin repair bond strength.

The aim of this study was to evaluate the trueness of 5 intraoral scanners (IOSs) for digital impression of simulated implant scan bodies in a partially edentulous model. A 3D printed partially edentulous mandible model made of Co-Cr with a total of 6 bilaterally positioned cylinders in the canine, second premolar, and second molar area served as the study model. Digital scans of the model were made with a reference scanner (steroSCAN neo) and 5 IOSs (CEREC Omnicam, CS3600, i500, iTero Element, and TRIOS 3) (n = 10). For each IOS's dataset, the XYZ coordinates of the cylinders were obtained from the reference point and the deviations from the reference scanner were calculated using a 3D reverse engineering program (Rapidform). The trueness values were analyzed by Kruskal-Wallis test and Mann-Whitney post hoc test. Direction and amount of deviation differed among cylinder position and among IOSs. Regardless of the IOS type, the cylinders positioned on the left second molar, nearest to the scanning start point, showed the smallest deviation. The deviation generally increased further away from scanning start point towards the right second molar. TRIOS 3 and i500 outperformed the other IOSs for partially edentulous digital impression. The accuracy of the CEREC Omnicam, CS3600, and iTero Element were similar on the left side, but they showed more deviations on the right side of the arch when compared to the other IOSs. The accuracy of IOS is still an area that needs to be improved.

Background This study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic. Methods Leucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatment; 2) SBU: Single Bond Universal (3M ESPE); 3) ABU: ALL-BOND Universal (Bisco); and 4) PC: RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Adhesive (3M ESPE) as a positive control. RelyX Ultimate resin cement (3M ESPE) was placed on the pretreated ceramic and was light cured. Eight specimens from each group were stored in water for 24 h, and the remaining eight specimens were thermocycled 10,000 times prior to microshear bond strength evaluation. The fractured surfaces were examined by stereomicroscopy and scanning electron microscopy (SEM). Results After water storage and thermocycling, the microshear bond strength values decreased in the order of PC > SBU and ABU > NC (P < 0.05). Thermocycling significantly reduced the microshear bond strength, regardless of the surface conditioning used (P < 0.05). Cohesive failure in the ceramic and mixed failure in the ceramic and resin cement were observed in the fractured specimens. The percentage of specimens with cohesive failure after 24 h of water storage was: NC (50%), SBU (75%), ABU (75%), and PC (87%). After thermocycling, the percentage of cohesive failure in NC decreased to 25%; however, yet the percentages of the other groups remained the same. Conclusions Although the bond strength between resin and hydrofluoric acid-etched glass ceramic was improved when universal adhesives were used, conventional surface conditioning using a separate silane and adhesive is preferable to a simplified procedure that uses only a universal adhesive for cementation of leucite-reinforced glass-ceramic.

Background This study presents different zirconia additive manufacturing (AM) materials and technologies while assessing the fit, hardness, and shear bond strength of crowns produced by AM and subtractive manufacturing (SM) methods, as well as their surface characteristics. Methods Zirconia crowns were fabricated using a 5-axis SM and five AM approaches, including four digital light processing principles and one stereolithography (SLA) technique. Each method utilized varying slurry delivery and light-curing mechanisms. The replica technique measured marginal and internal gaps (axial, line angle, and occlusal) between the crowns and abutments. The Vickers hardness and shear bond strength of crowns bonded with resin cement were assessed. Surface characteristics were analyzed with scanning electron microscopy (SEM) post-printing and sandblasting. The fit, hardness, and shear bond strength of crowns were manufactured through AM and SM methods. Sixty crowns were fabricated (10 per group). Statistical analysis was conducted using one-way analysis of variance (ANOVA) with Tukey post-hoc testing (α = 0.05). Results The marginal fits were 48.45 µm and 42.83 to 81.95 µm for the S and AM groups, respectively. Significant differences were observed between groups (< 0.001), although all measurements fell within the clinical acceptance range (120 µm). The Vickers hardness measurements revealed that the SM group had a hardness of 1473.87 HV, whereas those of the AM groups ranged from 1441.94 to 1532.53 HV, showing statistically significant differences ( P  < 0.001). Shear bond strength measurements displayed 7.97 MPa and 6.97 to 8.97 MPa for the SM and AM groups, respectively, with no significant differences between the groups. SEM analysis of the crown surfaces revealed agglomerated zirconia particles with various grooves after sandblasting. Conclusions Zirconia crowns produced through the AM and SM methods demonstrated clinically acceptable marginal fit and ideal hardness exceeding 1200 HV. Some AM groups demonstrated higher hardness and shear bond strength than the SM group. The diverse physical and mechanical properties of various zirconia AM technologies suggest their selective use in specific clinical situations. Certain AM techniques, such as SLA spreading demonstrated comparable or even superior results to those of SM in terms of fit and hardness, indicating their potential as viable alternatives in clinical settings.

Background Given the critical role of health professionals in societal health, the development of robust and effective selection methods is of fundamental concern for educational institutions within the field of health sciences education. Conventionally, admission competencies have been determined by institutional authorities. Developing institution-specific competency criteria enables an admission process that is mission- and value-aware, evidence-based, and strategically adaptable. However, few schools have established their admission competency criteria, although the majority possess their own models of graduation competencies. This study reports the process of developing and validating an institution-specific admission competency model that addresses the need for evidence-based and mission-aligned selection processes that are distinct from standardized models. Methods This study was conducted in two phases, using both qualitative and quantitative analyses. Phase I involved constructing an admission competency model through a qualitative approach facilitated by workshops with 17 faculty members and 92 first-year pre-doctoral students of a dental school. Through constant comparative analysis, this phase focused on the extraction and refinement of competencies for entering dental students. In Phase II, a questionnaire developed from the workshops asked respondents to rate the importance of 47 attributes across 10 constructs on a 5-point Likert scale. A total of 301 individuals participated in the survey. Exploratory Factor Analysis (EFA) identified the factor structure, and Confirmatory Factor Analysis (CFA) examined construct validity and assessed the model fit with the data. Results The EFA of the 47 attributes identified 10 factors, and the CFA results indicated a good-to-acceptable level of fit for the ten-factor model. Aligned with the American Association of Medical Colleges Premed competencies, this study identified unique attributes specific to the institution, such as confidence, leadership, and entrepreneurship. These findings highlight the importance of developing tailored competencies reflecting the unique needs of institutions and their fields. Conclusions This study demonstrates the feasibility and value of creating institution-specific admission competency models, offering a methodology that aligns with evidence-based mission-driven selection processes. The distinct competencies identified emphasize the need for educational institutions to consider unique institutional and field-specific requirements and move beyond standardized models to enhance the selection of medical students.

With the advent of 3D printing technologies in dentistry, the optimization of printing conditions has been of great interest, so this study analyzed the accuracy of 3D-printed temporary restorations of different sizes produced by digital light processing (DLP) and liquid crystal display (LCD) printers. Temporary restorations of 2-unit, 3-unit, 5-unit, 6-unit, and full-arch cases were designed and printed from a DLP printer using NextDent C&B or an LCD printer using Mazic D Temp (n = 10 each). The restorations were scanned, and each restoration standard tessellation language (STL) file was superimposed on the reference STL file, by the alignment functions, to evaluate the trueness through whole/point deviation. In the whole-deviation analysis, the root-mean-square (RMS) values were significantly higher in the 6-unit and full-arch cases for the DLP printer and in the 5-unit, 6-unit, and full-arch cases for the LCD printer. The significant difference between DLP and LCD printers was found in the 5-unit and full-arch cases, where the DLP printer exhibited lower RMS values. Color mapping demonstrated less shrinkage in the DLP printer. In the point deviation analysis, a significant difference in direction was exhibited in all the restorations from the DLP printer but only in some cases from the LCD printer. Within the limitations of this study, 3D printing was most accurate with less deviation and shrinkage when a DLP printer was used for short-unit restorations.

Objective. The aim of this study was to evaluate the temperature change at various sites within the composite and on the pulpal side of dentin during polymerization of two composite increments. Materials and Methods. Class I cavities prepared in third molars were restored in two composite increments ( n = 5 ). Temperatures were measured for 110 s using eight thermocouples: bottom center of cavity (BC), top center of 1st increment (MC), top center of 2nd increment (TC), bottom corner of cavity (BE), top corner of 1st increment (ME), top corner of 2nd increment (TE), pulpal side of dentin (PD), and center of curing light guide tip (CL). Results. Maximum temperature values (°C) measured during polymerization of 1st increment were MC (59.8); BC (52.8); ME (51.3); CL (50.7); BE (48.4); and PD (39.8). Maximum temperature values during polymerization of 2nd increment were TC 58.5; TE (52.6); MC (51.7); CL (50.0); ME (48.0); BC (46.7); BE (44.5); and PD (38.8). Conclusion. Temperature at the floor of the cavity was significantly higher during polymerization of 1st increment compared to 2nd increment. Temperature rise was higher at the center than at the corner and at the top surface than at the bottom surface of each increment.

This study evaluated the effect of vibration on adaptation of bulk-fill composite resin. A scanning laser doppler vibrometer measured the frequency and amplitude of a vibratory device (COMO; B&L Biotech) used for resin placement and visualized its effect on the resin according to depth. A bulk-fill composite resin (Filtek Bulk Fill; 3M ESPE) was placed in simulated cavities (4 mm diameter, 4 mm depth) by different layering methods (incremental filling with two 2-mm-thick layers vs. bulk filling with a single 4-mm-thick layer). The groups were further divided based on the application of vibration during restoration (no vibration vs. vibration). In addition to the surface void area at the cavity floor, the overall void volume and the void volumes of the bottom, middle, and top thirds were obtained for micro-computed tomography analysis. The frequency and amplitude of the COMO were approximately 149 Hz and between 26 and 51 µm, respectively. When vibration was not applied, incremental filling had a lower void volume in the bottom third of the cavity than did bulk filling ( p  < 0.05). Vibration applied with a 4-mm-thick bulk fill had no significant effect on the adaptation of composite resin ( p  > 0.05). In contrast, vibration reduced the amount of void formation in the bottom third of the cavity during incremental filling ( p  < 0.05). Application of vibration to resin with a 2-mm incremental-layering technique formed a smaller void at the interface between the cavity and resin and within the bulk-fill composite resin.