Development and Assessment of Discrimination Exercises for Faculty Calibration in Preclinical Operative Dentistry.

The aims of this study were to identify the level of interexaminer agreement among preclinical operative dentistry faculty members when grading Class II preparations performed by first-year dental students; to develop discrimination exercises for specific preparation components where interexaminer agreement was poor; and to evaluate if the discrimination exercises were able to improve inter- and intraexaminer agreement. In the preliminary phase of this study, 13 components of 32 Class II cavity preparations were assessed by eight course faculty members at one U.S. dental school. Analysis of average interexaminer agreement on these components revealed that six were below 60%. These were proximal contact clearance, retention groove placement, retention groove depth, preparation walls, preparation margins, and preparation toilet/debris. A 30-minute calibration session was subsequently developed to provide discrimination exercises utilizing 3-D models and digital images of various levels of student performance for five of the six components. Immediately following calibration, the course faculty assessed the same 32 preparations (Phase I) followed by a delayed assessment without calibration (Phase II) approximately six months later. The results showed that overall interexaminer reliability improved after calibration. Although there was a decline in interexaminer reliability after an interval of six months (Phase II), the degree of variation among examiners was lower than in the preliminary assessment. These findings support the use of discrimination exercises for preclinical operative dentistry course faculty to increase interexaminer agreement and thereby improve the consistency of faculty-student communication.