Incisal overjet and traumatic injuries to upper permanent incisors. A retrospective study.

The relationships between traumatic injuries to upper incisors and incisal overjet were studied in a sample of 1445 orthodontically untreated children aged 7 to 16 years. Traumatic injuries of the hard dental tissues and exarticulations of teeth were recorded. The frequently of injuries was 14.2% in children with normal overjet (0--3 mm), 28.4% in children with increased overjet (3.1-6mm), and 38.6% in children with extreme overjet (greater than 6 mm). The severity of injuries was also greater in children with extreme overjet than in children with overjet ranging from 0 to 6 mm. Furthermore, the range of injuries increased in relation to the overjet. Two or more injured incisors were found in 19.2% of the children with normal overjet, in 22.2% of the children with increased overjet, and in 46.7% of those with extreme overjet.