Premaxillary-maxillary suture asymmetry in a juvenile Gorilla. Implications for understanding dentofacial growth and development.

A specimen of juvenile gorilla was found that had the premaxillary-maxillary suture coursing between the lateral deciduous incisor and deciduous canine on one side of the jaw, but between the central and lateral deciduous incisors on the other; in the latter, the suture also separates the alveolus of the lateral deciduous incisor from the crypt of the growing successional lateral incisor. Rather than dismiss this exception to the traditional dictum of tooth identification--which is based on the position to teeth relative to this suture--as some inconsequential anomaly, an attempt is made to understand how this can occur within the confines of present understanding of dentofacial growth and development and developmental theory. An hypothesis relating tooth and tooth class identification is presented in the context of ectomesenchymally predifferentiated stem progenitors and subsequent tooth class proliferation.