Distribution of malocclusion types in 7-9-year-old Iranian children.

This study assessed the malocclusion types, very severe crowding and need for serial extraction among a random sample of 7-9-year-old children in Shiraz, Islamic Republic of Iran. Of the 3776 children 30.6% had normal occlusion, 47.4% class I malocclusion, 13.7% class II division 1 malocclusion (male/female ratio 3:2), 1.0% class II division 2 malocclusion (male/female ratio 3:1) and 2.1% class III malocclusion. Among the children examined, 47.9% had crowding problems and 14.7% of them had class I malocclusion with very severe crowding-more girls (17.3%) than boys (12.1%). No correlation was observed between the types of malocclusion and family size, parents' occupation or level of education.