Effectiveness of a structured rubric-based assessment in preclinical crown preparation training: a randomized...

Crown preparation is a core but challenging skill for dental students, often assessed through subjective methods with limited reliability. Analytical rubrics provide a structured and transparent approach to teaching and evaluation. This study assessed the effectiveness of a rubric-based assessment system in preclinical crown preparation training.

A randomized controlled trial was conducted with 90 fourth-year undergraduate dental students who met predefined eligibility criteria (mean age: 22 ± 1.2 years). Participants were randomly allocated in a 1:1 ratio using a computer-generated sequence to a control group (n = 45) evaluated conventionally and a test group (n = 45) evaluated using a structured rubric. Both groups prepared an all-ceramic crown on tooth #21 following standard instruction. The primary outcome was the total crown preparation score. Assessments were performed independently by calibrated examiners at baseline and post-training; student blinding was not feasible. No adverse events were reported. Independent and paired t-tests with Bonferroni correction were applied, effect sizes calculated, and post hoc power analysis performed using a 95% confidence interval. Student perceptions were collected using a six-item Likert-scale questionnaire.

Baseline comparisons had no significant differences (p = 1.0). At the end of training, the primary outcome show, test group demonstrated significantly higher scores across all parameters (all p < 0.001). Mean total score was 30.53 ± 4.99 in the test group versus 10.56 ± 4.34 in the control group (p < 0.001; Cohen's d = 4.21). Both groups improved significantly, with greater gains in the test group (22.91 ± 6.42 vs 2.93 ± 2.72). Post hoc power exceeded 0.99 for all outcomes. Student feedback was highly positive, with 95% affirming improved objectivity, self-reflection, and clarity of evaluation criteria.

The use of an analytical rubric was associated with higher crown preparation assessment scores and positive student perceptions regarding clarity and objectivity of evaluation. These findings suggest that rubric-based assessment may support structured performance evaluation and learner understanding in preclinical prosthodontic training.

Not registered. This study evaluated an educational assessment intervention in a preclinical academic setting and did not involve patients or health-related clinical interventions as defined under ICMJE criteria.