[Root dysplasias of human teeth: a review].

Tooth development is a complex physiological process, which goes through bud stage, cap stage, bell stage and root development stage. The aim of this review article is to report the clinical manifestations of root malformations and the mechanisms of root dysplasias of human teeth. The effects of epithelial root sheath on the development of tooth roots were also elaborated.牙齿发育是一个复杂的生理过程，经历蕾状期、帽状期、钟状期和牙根发育期。本文主要介绍人类牙根发育异常主要疾病的临床表现以及目前所知发病机制，并阐述上皮根鞘（epithelial root sheath）在牙根发育过程中的影响。.