Visualizing the future: impact of holographic visualization on teaching minimally invasive veneer preparation: a randomized controlled trial.

BACKGROUND: Minimally invasive veneer preparation in prosthodontic education requires advanced spatial understanding and psychomotor precision. Although immersive technologies are increasingly used in dental education, evidence regarding the educational effectiveness of holographic visualization in prosthodontics remains limited. This randomized controlled trial evaluated the impact of holographic visualization on preparation quality and student-reported educational outcomes during preclinical training in minimally invasive veneer preparation. METHODS: Sixty undergraduate dental students were randomly assigned to receive either conventional two-dimensional photographic visualization (n = 30) or holographic three-dimensional visualization (n = 30). Following a standardized calibration session and baseline preparation, participants performed a second veneer preparation after exposure to the assigned visualization modality. Preparations were independently assessed by two blinded evaluators using a predefined scoring rubric. Within-group changes were analysed using Wilcoxon signed-rank tests, and between-group differences were assessed using analysis of covariance adjusted for baseline performance. Student-reported outcomes were compared using Mann-Whitney U tests with false discovery rate correction. RESULTS: Both groups showed significant improvements in preparation quality from baseline to post-intervention (both p < 0.001). However, no significant between-group differences were observed (adjusted mean difference: 0.60 points; 95% confidence interval: -0.48 to 1.67; p = 0.269). Overall student-reported outcomes were comparable between groups. Spatial understanding showed the largest between-group effect in favour of holographic visualization, although this difference was not significant after correction for multiple comparisons. Holographic visualization was highly accepted by students, and 70% supported its future integration into dental education. CONCLUSIONS: Although holographic visualization did not significantly improve immediate preparation quality compared with conventional two-dimensional photographs, it was highly accepted by students and showed the largest observed effect for perceived spatial understanding. These findings suggest that holographic visualization may primarily support spatial understanding and represent a valuable adjunct for teaching complex three-dimensional concepts in preclinical prosthodontic education. TRIAL REGISTRATION: German Clinical Trials Register (DRKS), DRKS00040713, prospectively registered on 22 June 2026.