Criterion-oriented grading system for preclinical operative dentistry laboratory course.

The object of this study was to evaluate instructor reliabilities when using empirical or traditional and criterion-oriented grading methods. To do so, 52 sample preparations made in plastic teeth by freshman dental students in the preclinical operative dentistry laboratory course were graded by 12 instructors. The preparations included those for amalgam, inlay, and gold foil restorations. The instructors were divided into two groups according to their teaching experience. Intraclass correlation coefficients were calculated by using a one way analysis of variance technique. The criterion method, in general, yielded greater intraclass correlation coefficients. The increase in the intraclass correlation coefficient was found to be significant at the alpha = 0.10 error level for all restorations judged by experienced instructors. The different degrees of increase in correlation may be attributed to the vary ing clinical biases of the instructors and the differences in the types of preparations.