The prevalence of various dental characteristics in the primary and mixed dentition in patients born with non-syndromic unilateral cleft lip with or without cleft palate.

This retrospective study was carried out on consecutively collected dental casts, x-rays, and photos of 129 Swedish children who had been born with non-syndromic unilateral (U) cleft lip (CL), cleft lip and alveolus (CLA), or cleft lip and palate (CLP). The following dental characteristics were investigated in the primary and permanent dentitions: 1. the presence, eruption, position, and shape of the lateral incisor; 2. the prevalence of rotation and enamel hypoplasia of the permanent central incisor; 3. the occurrence of hypodontia outside the cleft region; and 4. the transition from the primary to the succeeding permanent lateral incisor in the cleft region. Patients with clefts involving the palate (UCLP) exhibited a high frequency of hypodontia. In patients with clefts, which did not include the palate, malformed lateral incisors were a common finding. In the primary and permanent dentition, the lateral incisor had erupted distal to the cleft in 31.8 and 24.8 per cent of the UCLA and UCLP patients, respectively. No significant pattern was seen regarding the transition from the primary to the succeeding permanent lateral incisor (P = 0.15). The central incisor was rotated in 55 per cent of the patients and this positional deviation was particularly frequent in cases where the lateral incisor was missing in the premaxilla (P < 0.05). Hypodontia outside the cleft region was recorded in 15.5 per cent of the patients. Patients with UCLP had more often crossbite than patients with a UCL or a UCLA phenotype (P < 0.001).