JMIR Publications

ABSTRACT

Background:

Minimally invasive dentistry requires precise visualization to preserve healthy tooth structure. In endodontics, access cavity preparation involves navigating the complex anatomy of the pulp chamber and root canal system, often requiring indirect vision using a dental mirror—a skill that is challenging for dental students to master. Although virtual reality (VR) simulators provide immersive environments for dental training, most existing systems primarily focus on procedural simulation and haptic feedback, with limited capabilities for real-time mirror positioning and indirect visual guidance.

Objective:

This study aimed to evaluate the effectiveness and usability of a VR-based mirror guidance system in improving indirect vision during minimally invasive endodontic access cavity preparation.

Methods:

Eligible fourth-year preclinical dental students were recruited through institutional email invitations and public announcements. A randomized controlled crossover trial was conducted with 20 participants, who completed all VR sessions in a simulation laboratory under direct investigator supervision to ensure standardized implementation of the training protocol. Participants performed simulated maxillary first molar access cavity preparations under four VR mirror guidance conditions—verbal guidance, visual guidance, haptic guidance, and no guidance—following a randomized 4 × 4 Latin square sequence with a 48-hour washout period between sessions. The primary outcome was the duration of maintaining visibility of the operating area. Secondary outcomes included operating area obstruction, operator posture error, task completion time, outcome error score, and scores from the Virtual Reality System Usability Questionnaire. Performance and usability outcomes were analyzed using crossover analysis of variance, with estimated marginal mean differences, 95% confidence intervals (CIs), effect sizes (η²ₚ), and post hoc Dunnett comparisons.

Results:

A significant overall effect of guidance condition on operating area visibility was observed (F(3,54) = 4.30, P = .012, η²ₚ = 0.193). Post hoc Dunnett comparisons demonstrated that visual guidance resulted in significantly greater operating area visibility than the no-guidance condition (estimated mean difference 41.69 seconds, 95% CI 4.10–79.27; P = .022). No significant differences were observed among the four conditions in operating area obstruction, operator posture error, task completion time, or outcome error score. Usability ratings were generally high across all guidance modalities; however, visual guidance received comparatively lower ratings for clarity and ease of use.

Conclusions:

This study evaluated a VR-based mirror guidance approach that extends conventional VR dental simulators by providing real-time feedback to support indirect mirror positioning and visuomotor alignment. Visual guidance selectively improved maintenance of the operative field, highlighting the potential of targeted guidance mechanisms for developing indirect vision skills. These findings contribute to the advancement of simulation-based dental education and provide a foundation for future adaptive VR training systems integrating optimized visual, verbal, and haptic feedback to enhance psychomotor skill acquisition. Clinical Trial: Thai Clinical Trials Registry (TCTR20260126008), https://www.thaiclinicaltrials.org/show/TCTR20260126008