ABSTRACT

Aim: To measure the convergence angle (CA) of tooth preparation for single metal-ceramic crown carried out by fourth and fifth-year undergraduate dental students and to compare angles with the recommended CA.

Design: Observational study Place and duration of study: Qassim University, College of dentistry, from January to June 2020 Methodology: A total of 45 preparations, made by 23 male and 22 female students, were randomly selected for evaluation of the buccolingual and mesiodistal convergence angles. Each tooth was scanned using Sirona Cerec 2 scanner to produce 3-dimensional digital object. A digital analysis software program ‘image j” was used to calculate the convergence angles for each abutment tooth. One sample t-test was used to compare the mean convergence angle values and two-sided t tests were performed to compare the buccolingual and mesiodistal angles between the genders.

Results: The mean mesiodistal convergence angle was 18.22 ± 7.99 degrees, and the mean buccolingual convergence angle was 16.55±8.51 degrees. The mean buccolingual convergence angle in preparations by male students was 16.16±10.19 degrees, compared with 16.96±6.52 degrees by female students, whereas, the mean mesiodistal convergence angle prepared by male students was 19.03±8.08 degrees, compared to 17.37±7.98 degrees by female students. No statistical difference was observed between the genders. The overall mean reported convergence angle value was 17.38 which was significantly greater (p < 0.000) than the recommended values.

Conclusion: There was a considerable difference between the CA values recorded in this study and the recommended guidelines. The recommended CA (<12°) was difficult to achieve clinically by the students.

Key words: convergence angle, tooth preparations, dental education, metal-ceramic crowns, dental students, pre-clinical training.