Relapse measurements in experimental tooth movements

Abstract

An experimental study of relapse after experimental orthodontic movements produced in rats with a specially designed appliance (López O tero et al (1973) J. Period. Res 8:327-333) is presented. The orthodontic dírice, which moved the upper first molars in a vestibular direction, was removed after 48 hours (Goup I) or 96 houn (Group II) of treatm ent. The animals in both groups were killed either 7 or 15 days after removal. The intermolar da tan ce was measured to evaluate tooth movement on casts prepared from the upper jaw. Relapse was proved in every case, being greater in Group I than in Group II. The histometric evaluation of alveolar bone was performed on histologic sections. It revealed an increment in bone formation areas in the alveolar surface in detriment of bone resorption and an increment of bone volume. These resuits demonstrated the real increment of alveolar bone following appliance removal.