Retention of preclinical knowledge by clinical students.

To form a sound foundation for clinical subjects, oral biology must be taught in such a way that information gained early in the dental course is remembered when required in the clinical years. Knowledge retention was assessed by having students answer 20 sets of five multiple answer, multiple choice items after one term's study of oral biology and the same test after a lapse of 20 months with no intervening teaching in the subject. An analysis of the results obtained in these tests is presented and the scores are compared with performance in other oral biology examinations. Performance in the professional examination was most highly correlated with the examination closest to it in time, although this was a practical examination and was considered to be measuring different skills.