Cleft type and Angle's classification of malocclusion in Korean cleft patients.

This study was performed to investigate the contributing factors, such as cleft type, side of cleft, patient's age, and gender, associated with Angle's classification of malocclusion in Korean cleft patients. The records of 250 cleft patients (175 males, 75 females) who attended the Department of Orthodontics, Seoul National University Dental Hospital between 1988 and 1999 were examined. The percentages of subjects with cleft lip (CL), cleft lip and alveolus (CLA), cleft palate (CP), and cleft lip and palate (CLP) were 7.6, 19.2, 9.6, and 63.6, respectively. The overall distributions of unilateral and bilateral clefts were 76 and 24 per cent, respectively. The overall percentages of Class I, II, and III malocclusions were 18.5, 8.8, and 72.7. The frequency of Class III malocclusions was most prevalent in all age groups. Bivariate analysis showed that whilst gender was not significant, the type of cleft significantly influenced the development of a Class III malocclusion (P < 0.01). Using logistic regression analysis, subjects in the CP (P < 0.05) and CLP groups (P < 0.01) were 3.9 and 5.5 times more likely to have a Class III malocclusion than those in the CL group. There was, however, no statistical difference in the prevalence of a Class III malocclusion between the CL and the CLA groups (P > 0.05). When the degree of cleft involvement in the palate increased, so did the predominance of a Class III malocclusion.