Inter-Rater Reliability and Acceptance of a Software-Based Digital Assessment of Preclinical Preparations: A Multicentre Analysis.

INTRODUCTION: In preclinical dental education, training in different tooth preparation techniques is an important part of teaching. Visual grading of prepared teeth by preclinical supervisors is often subjective. The development of a digital grading interface could improve objective assessment and the quality of teaching. The aim of this study was to determine the acceptance of a digital grading interface by preclinical supervisors and the inter-rater reliability. MATERIAL AND METHODS: A digital grading system was developed for preclinical training in which 78 prepared teeth were digitised and processed. All visualised teeth were imported into a digital grading system and graded by 49 examiners from three universities. Data were statistically analysed using the Kruskal-Wallis/Bonferroni and Fleiss-Kappa tests. RESULTS: In 35.0% of cases, there was a significant difference in dental grading between universities. A significant difference was found for grading classes 3 to 5. Grading classes 1.5 and 6 had an Interquartile range (IQR) of 0.5, Grade 2 had an IQR of 0.88, and 2.5, 3, 3.5, 4.5, 5 and 5.5 had an IQR of 1.0. Acceptance of the digital grading interface was around 88.0%. The inter-rater reliability of the 49 examiners was 0.11. CONCLUSION: Pre-clinical grading is highly subjective and can vary by up to one grade, so it is reasonable to assume that three grades are recommended to make grading more objective. In critical grading cases, the grading should be reviewed by different graders. The use of a digital grading interface could reduce the workload of assessors.