# Precision dentistry in preclinical education: analytic rubrics for enhanced objectivity in metal-ceramic crown preparations

## TL;DR

This study shows that using analytic rubrics improves objectivity and consistency in grading dental students' crown preparations.

## Contribution

The study introduces and validates an analytic rubric system for evaluating metal-ceramic crown preparations in dental education.

## Key findings

- The analytic rubric achieved substantial to almost perfect inter-rater reliability (kappa values 0.67–0.85).
- Examiner scores showed no significant differences, indicating consistent grading across evaluators.
- Finish line form and gingival protection received the highest scores, while incisal reduction and taper were weakest.

## Abstract

Preclinical dental training requires students to master precise tooth preparation skills that directly influence clinical success. Traditional grading methods often lack objectivity and consistency. Analytic rubrics, by deconstructing complex procedures into measurable components, may improve reliability and feedback in preclinical assessment. This study evaluated the application of an analytic rubric system for assessing anterior metal-ceramic crown preparations performed by undergraduate dental students.

A cross-sectional, double-blind study was conducted among fourth-year Bachelor of Dental Surgery students at King Khalid University. Forty-five students prepared the maxillary right central incisor for a metal-ceramic crown under standardized conditions. Preparations were independently evaluated by four calibrated prosthodontists using an analytic rubric comprising eight criteria, each scored on a 0–1 scale. Descriptive statistics, one-way ANOVA, and post hoc Tukey's HSD were employed to analyze examiner variation. Inter-rater reliability was assessed using Cohen's kappa.

The overall mean score across examiners was 3.436 ± 0.522. Among the parameters, incisal reduction (57.5%) and degree of taper (61.8%) recorded the lowest scores, while finish line form (76.9%) and gingival protection (76.4%) showed the highest. ANOVA indicated no significant differences among the four examiners across all parameters (p > 0.05). Tukey's HSD confirmed no pairwise examiner differences, demonstrating consistent grading. Inter-rater reliability yielded kappa values ranging from 0.67 to 0.85, indicating substantial to almost perfect agreement.

The analytic rubric proved to be a reliable and transparent tool for evaluating preclinical crown preparations, minimizing examiner subjectivity and enhancing feedback.