Earticle

Purpose: This study aimed to assess the effect of slicer-based tolerance compensation on the dimensional accuracy (trueness and precision) of dental models fabricated via masked stereolithography (MSLA) 3D printing. It focused on how different offset values affected the internal and external surfaces. Methods: Simplified, hollow, crown-shaped specimens were designed and categorized into four groups (A~D) based on the internal and external tolerance compensation values (−50 μm or 0 μm). Sixteen specimens per group were printed under identical conditions. After post-processing, the models were digitized with a dental scanner. The 3D deviations between the designed data (STEP) and scanned data (STL) were analyzed using Geomagic Control X. Conformity was quantified by root mean square (RMS) values. Results: Trueness analysis showed significant differences (p<0.001). For the internal surface, Group C (–50 μm internal, 0 μm external) showed the highest trueness (lowest RMS). Conversely, Group D (0 μm internal, 0 μm external) showed the highest trueness for the external surface. Precision analysis showed no significant differences among the groups (p>0.05). Color deviation maps confirmed that applying a –50-μm internal tolerance increased the surface area within the acceptable deviation range (±10 μm). Conclusion: Adjusting tolerance compensation in the slicer stage markedly influences the volumetric accuracy of the MSLA-printed dental models. These findings suggest that optimizing distinct tolerance parameters for internal and external surfaces is crucial for improving the dimensional accuracy and clinical fit of dental prostheses in the digital workflow.

Purpose: The present study aimed to assess the effect of palatal thickness and reinforcement insertion on the three-dimensional precision of the mucosal surface of maxillary denture bases after polymerization. Methods: Fifteen edentulous maxillary casts were fabricated and divided into three groups (n=5). The convention, complete denture, double-layer of base plate wax (CCD) group was fabricated with a double-layer baseplate wax without reinforcement. The reinforcement material, complete denture, double-layer of base plate wax (RCD) group used the same wax thickness with reinforcement insertion, whereas the reinforcement, complete denture, triple- layer of base plate wax (RCT) group was fabricated with triple-layer wax and reinforcement. After conventional heat polymerization, the mucosal surfaces were scanned, and the STL data were analyzed using best-fit superimposition. Precision was quantified by measuring the surface deviation values (μm), and the color difference maps were generated for visual analysis. Statistical analysis was performed using one-way ANOVA and Duncan’s post hoc test (α=0.05). Results: The CCD group showed the lowest mean surface deviation (46.69±10.65 μm), followed by the RCD group (63.10±16.70 μm), and the RCT group (82.76±20.94 μm). Significant differences were observed among all groups (p<0.001). The color difference maps revealed more uniform deviation patterns in the CCD group, whereas the RCT group presented with broader negative deviations in the central palatal region and mixed deviation patterns in the peripheral areas. Conclusion: Increased palatal thickness and reinforcement insertion significantly influenced the three-dimensional precision of the denture based-mucosal surface. Thus, structural optimization considering both reinforcement design and thickness control is required to maintain morphological stability.

Purpose: This study aimed to investigate the effects of microwave and conventional sintering methods on the marginal and internal fit of 3-unit full-contour zirconia bridges. Methods: The zirconia specimens were designed as 3-unit full-contour bridges, and a total of 20 units were fabricated. Ten specimens of each commercial zirconia brand were divided into two subgroups (n=10) and sintered at a maximum temperature of 1,530°C using two methods: conventional and microwave sintering. The marginal and internal fit of the preshaded zirconia prostheses was evaluated using the silicone replica technique, followed by the two-dimensional analysis. An independent sample t-test was then performed to compare and analyze the data between the two groups (α=0.05). Results: The results showed no significant difference in the fit of zirconia bridges between the groups (p>0.05). All specimens remained within the clinically acceptable limit of 120 μm, indicating that the microwave speed sintering protocol is suitable for clinical application. Conclusion: This study demonstrates the potential of the microwave sintering method as a viable alternative to conventional furnace sintering. It not only significantly reduces the processing time but also helps achieve a precise fit that ensures long-term clinical outcomes.

Purpose: The present study aimed to develop a resin-free computer-aided design/computer- aided manufacturing wax block and evaluate its milling accuracy and manual modifiability. The null hypothesis was that there would be no significant difference in the milling accuracy between the developed resin-free wax block (NPD) and the commercial LDPE-based wax block (LPD). Methods: An NPD block was fabricated using an optimized wax composition. Mandibular molar crowns (n=16 per group) were produced via five-axis dry milling. Milling accuracy was assessed through 3D superimposition (root mean square values) and one-way analysis of variance (α=0.05). Manual modifiability was qualitatively evaluated by an expert using an electric carver and optical microscopy. Results: The NPD group achieved stable dry milling without thermal deformation. No significant difference in milling accuracy was observed between the NPD and LPD groups (p>0.05), thereby supporting the null hypothesis. In the qualitative assessment, the NPD group exhibited superior carving properties and seamless fusion with modeling wax compared to the LPD group. Conclusion: The newly developed resin-free wax block maintains high precision comparable to commercial products while allowing greater manual modifiability. It serves as a practical alternative for enhancing efficiency in digital dental workflows.

Purpose: This study aimed to assess the level of awareness of Oral Health Day among community residents and to examine its associations with oral health behaviors, perceptions, and efforts to obtain oral health information, thereby exploring the role of Oral Health Day as a community-based oral health promotion strategy. Methods: A cross-sectional survey was conducted among residents of Gimcheon, Korea, from June 10 to July 31, 2025. Data were collected through an online questionnaire and a face-to-face survey administered to participants at the 80th Oral Health Day event. A total of 172 responses were included in the analysis. The data were analyzed using chi-square tests, independent-samples t-tests, logistic regression analysis, and multiple linear regression analysis. Results: Awareness of Oral Health Day differed significantly by age and educational level, with higher awareness observed among middle-aged and older adults and individuals with higher levels of education. Participants with higher awareness levels reported more frequent daily tooth brushing and were more likely to have participated in Oral Health Day events. Perceived importance of oral health was positively associated with awareness of Oral Health Day, whereas perceived preventability of oral diseases was negatively associated with awareness of Oral Health Day. In addition, higher awareness levels were associated with greater efforts to obtain oral health information. Previous experience with oral health education was not significantly associated with awareness of Oral Health Day. Conclusion: These findings suggest that Oral Health Day may serve as a public health mechanism that promotes oral health practices and information-seeking behaviors among community residents. Future Oral Health Day promotion and community oral health programs should integrate digital-based promotion strategies with community participation initiatives.

Purpose: This study aimed to investigate the association between denture and implant status and health-related quality of life (HRQoL) among Korean adults using data from the 9th Korea National Health and Nutrition Examination Survey (Year 2, 2023). Methods: This study included adults aged ≥19 years who completed the oral examination and responded to a questionnaire measuring their denture/implant status and the Healthrelated Quality of Life Instrument with 8 Items. Descriptive statistics, cross-tabulation, and correlation analyses were performed using SPSS version 22.0 (IBM). Results: Implant status was positively associated with most HRQoL domains, including stair climbing, pain, vitality, daily activities, memory, sleep, and happiness (r=0.058 to 0.182, p<0.01). In contrast, denture use showed significant negative correlations with the same domains (r=−0.071 to −0.181, p<0.01). Overall, implant users reported a higher quality of life, whereas denture wearers showed lower scores, particularly in physical and functional aspects. Conclusion: Prosthetic rehabilitation was significantly related to HRQoL beyond masticatory recovery. These findings highlight the importance of improving access to appropriate prosthetic treatments and provide evidence supporting oral health policies targeting older adults.