15-Point versus pass/fail grading in orthodontic education: A randomized controlled trial.

Objectives: There is a lack of evidence on whether a grading system or a pass/fail system influences manual skills in dental education. This parallel-group randomized controlled trial aimed to assess the influence of a 15-point grading system compared with a pass/fail evaluation on the quality of orthodontic appliances in dental education.

Methods: Predoctoral dental students of three orthodontic courses (n = 139) were randomly assigned to either the test group (15-point grading system) or the control group (pass/fail) using sealed envelopes. In both groups, the fabricated orthodontic appliances were assessed by five calibrated dentists using standard criteria. The primary outcome was the quality of the orthodontic appliances using a 15-point grading system. Group differences were evaluated with Mann-Whitney U tests and Fisher ́s exact tests.

Results: The quality of the orthodontic appliances was slightly higher in the test group (n = 68) compared with the control group (n = 70) in all three courses with mean grading values of 11.63 ± 0.75 versus 11.59 ± 0.99, 10.96 ± 0.83 versus 10.85 ± 0.82, and 10.93 ± 1.15 versus 10.14 ± 1.03. However, a statistically significant difference was found only in course 3 (p = 0.0222). Female participants performed better than males in all three courses (p = 0.0207).

Conclusion: The implementation of a 15-point grading system has a positive impact on the quality of appliances in orthodontic education and can be recommended. However, the differences were small and clinically meaningful in only one of the three courses evaluated.