Dentition of monozygotic twins concordant for Down's syndrome: a case report.

Examination of the dental casts of Down's syndrome twins showed a high percentage of concordance and mirror-imaging relative to crown morphology and static occlusion. These supplemental dental findings supported an earlier diagnosis of monozygosity determined by other clinical means. Reduction of mesiodistal dimension of the dental crowns and deviations in their morphology is consistent with Down's syndrome.