Digital 3D Assessment of Soap-Carved Tooth Morphology in Vietnamese First-Year Dental Students: A Cross-Sectional Study

To evaluate the reliability and educational applicability of a digital three-dimensional surface-deviation workflow for assessing soap-carved tooth morphology in first-year dental students.

Ninety-eight students completed the dental anatomy module. After written research consent and specimen eligibility screening, 41 students with complete evaluable sets of eight right-side tooth carvings were included (328 student-tooth models). Instructor-carved teeth served as reference models. Models were scanned with a Medit i700 and analysed in Medit Design. The primary outcome was root mean square deviation (RMS); secondary outcomes were percentages of surface area within 0.3-0.7 mm tolerance thresholds. Rater 1 repeated measurements after 2 weeks; Rater 2 independently measured the dataset once. Reliability was evaluated overall and by tooth type.

Pooled RMS intra-rater and inter-rater ICCs were 0.866 and 0.860, respectively. Tooth-stratified RMS ICCs ranged from 0.646 to 0.938 for intra-rater and 0.643 to 0.925 for inter-rater agreement. Overall mean RMS was 0.848 ± 0.365 mm. Mandibular central incisors showed the lowest mean RMS (0.553 ± 0.276 mm), whereas maxillary first molars showed the highest (1.357 ± 0.358 mm). At 0.5 mm, the overall mean surface within tolerance was 64.8%.

Digital surface-deviation analysis provided reproducible quantitative feedback overall, although reliability varied by tooth type. RMS and tolerance-based metrics can complement faculty judgement in manual tooth-morphology training but should not be interpreted as standalone grades.