Malocclusion and Orthodontic Treatment Need among 12-15-year-old Children in Nairobi.

OBJECTIVE To describe the pattern of occurrence of malocclusion and orthodontic treatment need. DESIGN A descriptive cross-sectional survey. SETTING Six public primary schools in Nairobi, Kenya. SUBJECTS A randomly selected sample of 1382 children aged 12 to 15 years. Clinical examination for malocclusion was conducted using the Dental Aesthetic Index (DAI). Orthodontic treatment need was derived using the regression equation stated in the DAI. RESULTS Among the 1382 (672 males and 710 females) children examined, 70 children (5.1%) had missing teeth. Crowding and spacing in the incisal segments occurred in 652 (47.2%) and 644 (46.6%) children respectively. Anterior irregularities were found in 533 (38.6%) of the subjects in the maxilla and 430 (31.1%) in the mandible. Anterior crossbite was found in 86 (6.2%) of the children. The anterior open-bite occurred in 194 (14%) of the children with significantly more open-bite in females than males (p=0007). The maxillary median diastema and antero -posterior molar relation discrepancies were found in 289 (20.2%) and 344 (24.9%) of the sample respectively. The sample mean DAI score was 26.6 (SD 7.8). Seven hundred and thirty two (53.0%) of the children examined had either no need or slight need for treatment whereas 650 (47%) were found with orthodontic treatment needs ranging from elective 318 (23%), highly desireable 176 (12.7%) to mandatory 156 (11.3%). CONCLUSION There was an overall high prevalence of malocclusion with 11.3% of the sample exhibiting handicapping malocclusion. Notably, there were no significant gender differences for most of the traits except for anterior open-bite which was found to occur more in females than males.