Occlusal disharmonies in mongolism (Down's syndrome)

Abstract

Class I. Twenty-three (46 per cent) Class I relationships with the following irregularities: Right lingual unilateral posterior cross-bites; bilateral lingual posterior cross-bites; anterior open-bites; anterior cross-bites of lateral incisors and end-to-end occlusion; anterior cross-bite; overjet; anterior flaring; maxillary anterior crowding; bimaxillary protrusion. Class ZZ. Sixteen (32 per cent) Class II relationships, twelve Class II, Division 1, and four Class II, Division 2. CZass ZZZ. Eleven (22 per cent) Class III relationships. The most striking feature in evaluating the occlusal relationships in this group was the high incidence of Class III relationships and the prevalence of lingual unilateral and bilateral posterior cross-bites. In a high percentage of the cases studied, a contributing factor to the Class III relationships and the posterior cross-bites was a generalized reduction in palatal width and length. The tongue played a minor role in the Class III relationships, since there were only a small number of cases (two) that manifested a true macroglossia. Occlusal disharmonies are pathognomonic of Down’s syndrome in the present study, since in no single instance was there a harmonious occlusal relationship.