Oral manifestations seen in association with a case of trisomy for the short arm of chromosome 9.

A case of trisomy for the short arm of chromosome 9 in a 13-year-old boy is described. Particular emphasis is placed upon a number of abnormal dental findings, which include enamel hypoplasia, hypodontia, and severe dental crowding. The difficulties of providing comprehensive dental treatment in cases such as these is discussed.