Posterior crossbite - treatment and stability

posterior crossbite is defined as an inadequate transversal relationship of maxillary and mandibular teeth. even when eliminating the etiologic factors, this malocclusion does not have a spontaneous correction, and should be treated with maxillary expansion as early as possible. this treatment aims at providing a better tooth/skeletal relationship, thereby improving masticatory function, and establishing a symmetrical condyle/fossa relationship. should posterior crossbite not be treated early, it may result in skeletal changes, demanding a more complex approach. additionally, an overcorrection expansion protocol should be applied in order to improve the treatment stability. although the literature has reported a high rate of relapse after maxillary expansion, the goal of this study was to demonstrate excellent stability of the posterior crossbite correction 21 years post treatment.