Relationship of third molar development and root angulation.

Angled roots are seen in mandibular third molars, which have a high frequency of incomplete impaction. We examined the relationship between incomplete impaction and angled roots. We enrolled orthopantomographs to determine the prevalence of angled roots in 239 men and 222 women aged 21--35 years with bilateral mandibular third molars. Angled roots were more frequent in subjects in whom the third molars had a different status on each side than in those with the same status on both sides (men: P<0.05; women: P<0.01). The incidence of women with angled roots in those with bilateral incomplete impactions was higher than that in those with bilateral eruption (P<0.01). Angled roots among mandibular third molars are related to environmental factors. Angled roots occur more frequently in women with incomplete impaction than in those with full eruption.