Dental education in order to be accepted to an American dental school, most candidates must possess at least a bachelor's degree, which requires the successful completion of all appropriate pre-requisite courses. The first 2 years of dental school consist mostly of didactic education, in addition to simulation courses[clarification needed]. The last two years generally involve direct patient care under supervision. There tends to be much overlap in most schools' curricula; the didactic years may have some clinical components, while the last two years still have significant didactic coursework.