Variations in occlusal and space characteristics in a series of 6-18-year olds, in Ilala District, Tanzania.

This study was carried out in Ilala District, Tanzania as part of a major oral health survey. The aim of the study was to investigate the variation in different occlusal and space characteristics among children and adolescents in different age group. A total of 698 children and adolescents aged 6-18 years were examined clinically. The subjects were categorized into three age groups, 6-9 years with early mixed dentition, 10-14 years with late mixed dentition and 15-18 years with permanent dentition. The examiners were calibrated before the survey and the agreement was satisfactory. Anteroposterior relationships of the dental arches were measured according to Angle's classification. Other occlusal and space variables included overjet, overbite, openbite, crossbite, crowding, spacing, and separate determination of diastema mediale. Most of the subjects in different age groups, 93-96%, had Angle's Class I molar occlusion. Large overjet (> 5 mm) occurred in 3-5% of the subjects. Deep bite (> 5 mm) was observed in about 2% of the children in all age groups. Anterior open bite was the most prevalent occlusal anomaly in all age groups, noted in 9-13% of the subjects. Transversal occlusal anomalies were rare. More than 33% of the subjects had spacing while less than 10% had crowding of the dentition. These results indicate that using the present criteria, most 6- to 18-year olds in Ilala district have optimal sagittal occlusion and a lot of spacing. The most common occlusal anomaly was anterior openbite.