Reliability of Faculty Evaluations of Dental Students' Grades in Prosthodontics

Objectives: Convergence angles for complete crown preparations have been recommended at 4-12 degrees. This study investigated the variability of faculty evaluation on student scores when assessing complete crown tooth preparations at Faculty of Dentistry, King Abdulaziz University, Saudi Arabia.

Methods: The convergence angles of 70 tooth preparations for complete crowns were evaluated. These comprised a random sample of upper left second premolar teeth prepared by fifth year dental students on dentoform under preclinical exam conditions. Two senior faculty members evaluated the bucco-lingual (BL) and mesio-distal (MD) convergence angles of each preparation. To determine consistency among raters an interrater reliability analysis was performed using the Kappa statistics.

Results: The lowest MD convergence angle evaluation was (13.9+7.9) degrees and the lowest BL evaluation was (10.1+5.5) degrees. The interrater reliability was found to be Kappa = -.047 (p<.0001) for MD and Kappa = .040 (p<.0001) for BL between the evaluators

Conclusions: There was a substantial disparity between the convergent angles evaluated in this study and the ideal configurations recommended in Fixed Prosthodontics textbooks and the dental literature. The student grades were moderately related to the evaluated convergence angles. Interrater reliability showed poor agreement between the two eveluators