Abstract
A clinical observation on 370 traumatized permanent teeth of 202 children was conducted from September 1979 to March 1994 in the Pedodontic Department, Niigata University. The prognoses were surveyed for 49 teeth.
The results are summarized as follows:
1) The highest incidence was found in children 8 years of age, with 7 and 9 years following in order.
2) Boys were more traumatized than girls with a ratio of about 2: 1.
3) The upper central incisors were most frequently affected.
4) The number of traumatized teeth per child was a range of two in over 80%of the cases.
5) The main causes for trauma were falling down, with colliding and dropping next.
6) Loosening was the most frequent, and crown-fracture without pulp exposure was next.
7) Fracture of the teeth was less commonly found in children aged under 7 year than in those over 8 years old.
8) Long-term observations of traumatically injured immature permanent teeth are necessary until completion of permanent dentition at least.
