Patterns of incisor root resorption before and after orthodontic correction in cases with anterior open bites.

External root resorption is a frequent iatrogenic consequence of orthodontic treatment, particularly in the maxillary anterior teeth. Since resorption also occurs is a normal function of aging and since altered behaviors such as bruxism and chronic nailbiting accelerate resorption even in the absence of treatment, it was hypothesized that the long-term orthopedic forces of tongue thrusting leading to anterior open bites would also enhance the rates of clastic activity. In a series of 32 adolescents with open bites, the roots of permanent maxillary central incisors were significantly shorter and exhibited higher modal grades of periapical resorption than a matched series with deep bites before treatment. The open bite group also had less facial bony support for these teeth. Both series experienced discernible resorption during full-banded treatment but to comparable extents so that, after active treatment, the open bite series continued to possess significantly greater degrees of resorption. Consequently, the oral forces leading to apertognathia are themselves destructive of root integrity and merit early recognition and interception.