The Convergence Angle of Full-coverage Crown Preparations Made by Dental Students

Objective: a clinically feasible convergence angle in full-coverage crown preparations, meeting the requirements for proper retention and resistance forms, has always been a matter of interest for laboratory and clinical researches. this study aims to evaluate the angle in teeth prepared by both under- and post-graduate students at tehran university of medical sciences, faculty of dentistry, department of prosthodontics. materials and methods: samples consisted of 196 prepared teeth for full-coverage crown restoration by third year postgraduate and fifth year undergraduate students in the department of prosthodontics. two images were obtained from each die by a scanner and both bucco-lingual and mesio-distal convergence angles were measured, by two different assessors, via auto cad 14 software. the data were analyzed using analysis of variance. results: there were statistically significant differences between the teeth prepared by un-der- and post-graduate students in mesio-distal convergence angles of all maxillary teeth, except for canines. significant differences were found between bucco-lingual convergence angles of the maxillary canines and molars. conclusion: the recently recommended convergence angles are more clinically feasible compared to the classic 4 to 10 degrees that was previously suggested for all teeth. it also seems that clinical experience does not necessarily lead to a decrease in convergence an-gles during preparation.