Tooth eruption in patients with cleft lip and palate.

In boys with a total unilateral cleft the course of eruption of deciduous and permanent teeth in the quadrant of the maxilla with the cleft was investigated and compared with the intact quadrant of the maxilla. The greatest retardation (two years) during eruption was found in deciduous and permanent second incisors in the maxillary quadrant affected by the cleft. This retardation is according to the authors associated with gross morphological changes such as duplication of the second incisor and its altered shape. The second upper permanent incisor erupts only in 60% of the patients and this can be explained by frequent hypodontia. Retarded eruption was observed also in the maxillary quadrant with the cleft in the permanent canine (one year), the first (one and a half year) and second permanent premolar (six months). In these teeth the crowns are not perceptibly malformed and the delayed eruption may be associated with lack of space in the hypoplastic quadrant of the maxilla on the side of the cleft. The permanent first incisor and permanent first and second molar erupt symmetrically in both maxillary quadrants.