Earticle

Purpose: This study aimed to assess the effect of build angle on the trueness of the internal and marginal areas of digital light processing–printed anterior zirconia cores. Methods: A prepared maxillary central incisor was scanned, and a core was designed using the dental computer-aided design (CAD) software. The core was positioned at build angles of 30°, 60°, and 90°. A 90° build angle was defined as the core’s long axis being perpendicular to the platform. After printing, washing, debinding, and sintering processes were performed (n=10 per group). For trueness evaluation, the printed cores were scanned and superimposed onto the reference CAD data, while the root mean square (RMS) values were measured. Statistical analysis was performed using one-way ANOVA and Tukey’s HSD test. Results: In the internal segment, the 30° group (57.38±7.93 μm) showed significantly higher RMS values than the 60° (39.59±3.41 μm) and 90° (36.71±7.60 μm) groups (p<0.001), whereas no significant difference was observed between the 60° and 90° groups. Similarly, in the marginal segment, the 30° group (61.83±8.13 μm) showed significantly higher RMS values than the 60° (43.19±3.36 μm) and 90° (40.51±8.77 μm) groups (p<0.001), whereas no significant difference was observed between the 60° and 90° groups. Conclusion: Due to the limitations of this in vitro study, the 60° and 90° build angles showed lower RMS values than the 30° build angle in both the internal and marginal areas. Among the tested conditions, the 90° build angle showed the lowest mean RMS values.

Purpose: This study was conducted to evaluate the effect of post-curing and interproximal connection thickness on the three-dimensional (3D) trueness of artificial teeth for 3D-printed dentures. Methods: Complete-arch artificial teeth were designed with interproximal connection thicknesses of 60%, 80%, and 100%, and 10 specimens were fabricated for each group using a digital light processing printer. Specimens were scanned before and after post-curing, and the scan data were superimposed on reference data using best-fit alignment. 3D trueness was evaluated based on deviation measurements and color difference maps. Data were analyzed using the Kruskal–Wallis and Wilcoxon signed-rank tests. Results: Before post-curing, median deviations were 94.30, 91.70, and 86.95 μm for the 60%, 80%, and 100% groups, respectively, with a significant difference among the groups (p=0.002). After post-curing, median deviations increased to 140.30, 121.65, and 119.40 μm, respectively, with a significant difference among groups (p=0.001). Significant differences between pre- and post-curing measurements were observed for all connection thicknesses (p=0.005). Color difference maps showed greater negative deviations after postcuring and relatively broader areas of low deviation in the 100% group than in the 60% group. Conclusion: Post-curing significantly affected 3D trueness across all connection thicknesses. Greater interproximal connection thicknesses were associated with lower deviations and improved dimensional stability. Therefore, connection thickness and dimensional changes induced by post-curing should be considered when designing 3D-printed denture prostheses.

Purpose: This study compared the optical properties of pre-shaded zirconia processed by dual-heating microwave sintering versus conventional sintering and evaluated its clinical applicability. Methods: Pre-shaded zirconia blocks were milled into 10.0×10.0×1.5-mm specimens and divided into the conventional sintering (CS) and microwave sintering (MS) groups. Sintering was performed at 1,530℃ as per the manufacturer instructions. Commission Internationale de l'Éclairage (CIE) L*, a*, b* values were measured using a spectrophotometer to calculate color difference (ΔE*) and translucency. Statistical significance was analyzed using an independent-samples t-test (α=0.05). Results: Sintering methods showed statistically significant differences in CIE L*, a*, b* values (p<0.001). The MS group exhibited decreased lightness (L*) and redness (a*), and increased yellowness (b*), alongside higher translucency (all p<0.001). The mean color differences did not reach the visual perceptibility threshold (ΔE≤1.6), and despite minor deviations in maximum values, all color differences reached the clinical acceptability threshold (ΔE≤3.7). Conclusion: This in vitro study revealed that dual-heating microwave sintering provided clinically acceptable color stability alongside enhanced translucency. However, considering study limitations, further investigations evaluating anatomical restoration designs and clinical settings are warranted to fully establish its efficacy as an alternative to conventional sintering.

Purpose: This in vitro study was conducted to compare dimensional accuracy and buildplatform uniformity among three vat photopolymerization dental 3D printing systems using a 20-mm cross-shaped specimen. Methods: Three printer–material–post processing systems were evaluated: Form 4B with Precision Model Resin (Formlabs), NBEE (UNIZ) with TC-80DP (Graphy), and MAZIC L-200 with Model 2.0 (VERICOM). Eleven cross-shaped specimens were distributed across the build platform, and X- and Y-dimensions were measured using a digital caliper. Five replicate print sets per system were analyzed. Absolute deviation from the target of 20.00 mm was the primary accuracy measure, and positions were classified as center, edge, or corner. Kruskal–Wallis and post hoc Mann–Whitney U tests were used for comparisons among systems, and Friedman tests were used for regional comparisons. Results: The mean absolute deviations were 173±4, 22±9, and 22±3 µm for Form 4B, NBEE, and L-200, respectively (p=0.009). Form 4B differed significantly from NBEE and L-200 (adjusted p=0.024), whereas NBEE and L-200 did not show significant difference (p=0.841). Form 4B showed systematic undersizing (signed deviation, −173±4 µm). Regional differences were significant for Form 4B (p=0.007) and L-200 (p=0.008), but not for NBEE (p=0.165). Conclusion: The three printer–material–post processing systems exhibited different patterns of dimensional error and spatial variation. Multi-position evaluation captured patterns that could be missed by center-only measurements, supporting the assessment of the printing system as an integrated workflow rather than based on printer hardware alone.

Purpose: This study examined the independent association between history of primary molar crown treatment and oral hygiene status of anterior teeth in children with mixed dentition using quantitative light-induced fluorescence (QLF). Methods: This retrospective cross-sectional study was conducted among 60 children aged 9 and 10 years (n=30 in each group). Qraycam Pro (AIOBIO) was used to collect fluorescent plaque index scores for the anterior teeth. Due to non-normal data distribution, the Mann– Whitney U test and rank-transformed two-way analysis of variance were used to compare plaque indices according to the presence of primary molar crowns (n=25) and age. To determine independent association, multiple linear regression analysis was performed after adjusting for sex, age, dental visit frequency, and baseline caries experience (decayed and filled teeth index). Results: Median fluorescent plaque index of the anterior teeth in the group with primary molars (2.80) was significantly higher than that in the control group (1.80) (Z=–3.842, p<0.001). No significant differences or interaction effects were observed between the groups with children aged 9 and 10 years (p>0.05). Regression analysis revealed that the presence of primary crowns was independently associated with increased plaque accumulation on anterior teeth (β=0.42, p<0.001). Conclusion: History of primary molar prosthetic treatment serves as a critical clinical risk marker for poorer oral hygiene status in the anterior region. Clinical protocols should incorporate periodic full-mouth QLF screening of standardized anterior teeth following posterior treatment, providing tailored oral hygiene interventions based on visual feedback.

Purpose: This study investigated the association between cumulative health-risk behaviors and poor self-rated oral health among Korean adults using data from the 2024 Korea National Health and Nutrition Examination Survey. Methods: In total, 4,771 adults aged ≥19 years were analyzed. Five health-risk behaviors (current smoking, high-risk drinking, physical inactivity, obesity, and short sleep duration) were scored and summed. Differences in self-rated oral health were assessed using chisquare tests, and logistic regression analyses were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: The prevalence of poor self-rated oral health was 17.6%, 25.7%, 27.5%, and 31.0% among participants with 0, 1, 2, and ≥3 health-risk behaviors, respectively (p<0.001). After adjustment for sex, age group, household income, education level, and marital status, the adjusted ORs for poor self-rated oral health were 1.39 (95% CI, 1.13~1.72), 1.39 (95% CI, 1.12~1.73), and 1.64 (95% CI, 1.27~2.10) for participants with 1, 2, and ≥3 health-risk behaviors, respectively, compared with those with none. Conclusion: A higher number of health-risk behaviors was significantly associated with poor self-rated oral health. These findings suggest that multiple health-risk behaviors should be considered when assessing and promoting oral health among adults.

Purpose: This study aimed to investigate the levels of grit, stress coping, and college life adjustment among dental technology students and identify the effects of grit and stress coping on their adjustment to college life. Methods: A cross-sectional survey was conducted among 151 second- and third-year students pursuing dental technology students at a college in Daejeon, Korea. Data were collected using self-administered questionnaires. The survey included the original grit scale, stress coping scale, and college adjustment scale. Data were analyzed using descriptive statistics, independent t-test, one-way analysis of variance, Pearson’s correlation coefficients, and multiple regression analysis with IBM SPSS Statistics 22.0. Results: The participants demonstrated mean scores of 3.05±0.48 for grit, 3.43±0.43 for stress coping, and 3.41±0.67 for college life adjustment. Among the subdomains of college life adjustment, personal psychology (3.68±0.80) and academic activities (3.67±0.83) scored higher. College life adjustment differed significantly according to academic achievement and peer relationship satisfaction (p<0.05). Grit and stress coping were positively correlated with college life adjustment. Multiple regression analysis showed that grit (β=0.48, p<0.01) and stress coping (β=0.40, p<0.01) were significant predictors of college life adjustment, accounting for 43.2% of the variance. Conclusion: Grit and stress coping were identified as significant factors associated with college life adjustment among dental technology students, with grit showing stronger association.

Purpose: This study aimed to assess the current status of oral health guidance and the challenges faced by guardians of lower-grade elementary school students, identify the factors associated with their needs for oral health education information, and provide foundational data for the development of simulation-based oral health educational materials. Methods: A survey was conducted among 148 guardians of lower-grade elementary students. Data were analyzed using frequency analysis, Pearson’s chi-square test, and binary logistic regression analysis with SPSS version 26.0 (IBM). Results: Among the 148 participants, 82.4% reported brushing their teeth twice or less per day, while “explaining correct brushing techniques” (48.6%) was identified as the most common challenge in providing oral health guidance. The highest educational demand was for “managing the tooth-exchange period” (44.6%), with “Text/SNS links” (61.5%) being the most preferred delivery method. Binary logistic regression analysis showed that guardians with negative dental experiences had approximately 4.06 times higher odds of belonging to the high information-need group (odds ratio=4.059, 95% confidence interval=1.672~ 9.852, p=0.002). Conclusion: Educational simulation materials should emphasize practical demonstrations of tooth-brushing techniques, tooth-exchange management, and individualized product selection. Furthermore, mHealth-based digital delivery channels (Text/SNS) should be actively utilized to bridge the gap between knowledge and behavioral practices.

Purpose: This study aims to investigate and analyze interpersonal and communication factors influencing clinical practice adaptation among dental technology students following the mandatory implementation of field training courses in 2024, and to provide foundational data for improving clinical practice adaptability and enhancing satisfaction. Methods: This study analyzed a total of 224 questionnaires completed by students from dental technology programs located in Gangwon-do and Gyeonggi-do who voluntarily participated in the survey after taking part in on-site clinical rotations at dental laboratories. The data were analyzed using SPSS Statistics ver. 22.0 (IBM) through descriptive analysis, ttests, ANOVA, correlation analysis, and linear regression analysis. Results: The average scores of the study participants were as follows: interpersonal competence score of 3.83, communication skills score of 3.60, adaptation to clinical practice score of 3.78. The explanatory power of the model was 27.5%. Among factors that influence adaptation to clinical practice, the ‘understanding’ factor (r=0.462), and among factors that influence communication, the ‘linguistic’ factor (r=0.347) showed the highest positive correlation. Additionally, in adaptation to clinical practice, both satisfaction within the academic programme and satisfaction within clinical practice showed statistically significant differences across all sub-factors (p<0.001). Conclusion: Communication, friendliness, and comprehensibility in interactions with clinical staff play key roles in clinical adaptation and satisfaction. Therefore, departments should provide pre-placement training for junior students, including clinical site orientation and clear assessment criteria, while also offering staff education on generational communication differences, along with standardized guidelines and objective evaluation frameworks.

Purpose: This study was conducted to compare the scope of practice and service-supply structure of dental technicians in Korea with selected international jurisdictions to identify institutional differences and policy implications. Methods: A qualitative policy and comparative institutional analysis was conducted using Korean laws, judicial precedents, insurance data, and policy documents, together with regulations and literature on Denturists in Ontario, Canada, Clinical Dental Technicians in the United Kingdom, and Dental Prosthetists in Australia. The analysis covered scope of practice, legal frameworks, reimbursement, service-supply structures, and professional autonomy. Results: In Korea, dental technicians may fabricate, repair, and process dental prostheses; however, they are restricted from performing intraoral procedures and independent reimbursement claims, resulting in an indirect supply system centered on dental clinics. In Ontario, Canada, the United Kingdom, and Australia, defined levels of patient contact and professional service provision are permitted within jurisdiction-specific education, registration, and accountability frameworks. Differences were identified in legal status, scope of practice, patient contact, professional accountability, and service/payment relationships. The potential effects on workforce retention, quality control, patient safety, and service sustainability were not empirically assessed. Conclusion: The scope of practice of dental technicians should be considered together with reimbursement arrangements, service-supply structures, and professional autonomy. Foreign professional models should not be directly generalized to Korea because education, registration, professional accountability, patient safety, and reimbursement systems differ. Potential associations with workforce sustainability, quality control, patient safety, and service sustainability warrant further empirical investigation.