Reliability of a Novel Grid-Based Dental Rubric as an Effective Assessment Tool for Evaluating Class II Tooth Preparations in Preclinical Settings

Introduction Assessment of preclinical operative skills is often limited by subjectivity and inconsistent grading. Traditional glance-and-grade methods provide minimal formative feedback. Criteria-based rubrics may improve objectivity, reliability, and learning outcomes in preclinical dental education. The aim of the present study was to test the reliability of a novel, criteria-weightage-based rubric for the evaluation of Class II restorations in preclinical settings. Methods A purposive sample of 10 subject-matter experts and 10 non-subject-matter experts was selected, and the rubric document was shared with them. Face Validity Index (FVI) and Content Validity Index (CVI) were calculated. The validated rubric was pilot-tested to evaluate preclinical competency in Class II cavity preparation (N = 36 BDS second-year students). Agreement between scores of two sets of evaluators using the traditional and rubric methods was used to measure inter-examiner reliability (consistency), and agreement between scores of the same examiners evaluating the same preparation after a seven-day washout period was an indicator of intra-examiner reliability (reproducibility). Results The rubric exhibited an adequate FVI of 0.96 and CVI of 0.98. The rubric's inter-examiner reliability and intra-examiner reliability were significantly higher than those of traditional methods. For the rubric method, the intraclass correlation coefficient (ICC) showed moderate agreement (ICC = 0.526), while the Pearson correlation coefficient indicated a statistically significant positive correlation between observers (r = 0.584, p < 0.001). Overall, the rubric-based method produced consistently higher ICC values for intra-examiner reliability (0.573-0.600) compared with the traditional method (0.265-0.396). Conclusion Based on the findings of the pilot study, the rubric-based assessment method is recommended as the primary tool for evaluating preclinical cavity preparations, as it demonstrated comparatively better inter- and intra-observer reliability than the traditional glance-and-grade approach.