Etiological and predisposing factors related to traumatic injuries to permanent teeth.

Etiological and predisposing factors related to traumatic injuries to permanent teeth were studied in an epidemiological material comprising 1610 children with 286 registered traumatic dental injuries. The results showed that (1) postnormal occlusion, (2) an overjet exceeding 4 mm, (3) short upper lip, (4) incompetent lips, and (5) mouth breathing were all factors which significantly increased susceptibility to traumatic dental injury. The average overjet in children with injuries limited to enamel fracture was 4.3 mm. In cases exhibiting more severe injuries (dentine fracture, pulp lesion, root fracture, exarticulation) the mean overjet was significantly greater, 5.0 mm. The most common causes for injury were 'falls and blows' which were recorded as etiological factors in 69.9% of the boys and in 86.7% of the girls. Dental injuries sustained during participation in sports were twice as common in boys (18.2%) as in girls (8.2%). The frequency of tooth injuries caused by traffic accidents was comparatively low, 9.7% in boys and 5.5% in girls.