Relapse after rapid palatal expansion

Abstract

We investigated the morphological changes in the dental arch and skull, and histological changes in the sutures of the nasomaxillary complex after retention following rapid platal expansion. Morphological analysis based on model measurements, frontal and lateral head x-rays, and occlusal radiography revealed that relapse occurred even in animals retained for 6 months, and that the incidence of relapse of the nasomaxillary complex increased as the retention period became shorter. Relapse occurred more frequently in the posterior region of the dental arch than in the anterior. After three months of retention, normal histological features were observed except in the frontomaxillary and frontozygomatic sutures, where there was extension of connective tissue fibers.