Frontal Cephalometric Comparative Study of the Dentoskeletal Effects induced by Three Rapid Maxillary Expansion Appliances

Danilo Furquim SIQUEIRA, Renato Rodrigues de ALMEIDA, Jose Fernando Castanha HENRIQUES

This cephalometric comparative study analyzed the effects of three types of rapid maxillary expansion (RME) appliances, with the objective of observing, by means of frontal cephalograms, the dentoskeletal alterations resulted from the expansion and the possible differences among the used appliances. The sample consisted of 63 patients (23 male and 40 female) divided into three groups: - Group I, composed by 20 patients that used the modified Haas expander, being 12 female and 8 male, aged 13 years and 5 months in average by the time the appliance was applied; - Group II, composed by 21 patient that used the modified Hyrax type appliance, 14 female and 7 male, aged 12 years and 10 months in average by the time the appliance was applied, and - Group III, composed by 22 patients that used the bonded rapid palatal expansion appliance, 14 female and 8 male, aged 12 years and 5 months in average by the time the appliance was applied. All patients were x-rayed in the preexpansion phase, immediately after the expansion, and after three months of active retention with the appliance, totalizing 189 posteroanterior radiographs for the accomplishment of this study. Based on the employed methodology and in the obtained results, it was verified that: - the three appliance types demonstrated similar orthopedic results, like the increase of the inferior portion of the nasal cavity and of the maxillary width, which were kept stable during retention period; - the maxillary molars (anchorage teeth) showed similar behavior; - the mandibular intermolars distances increased in the three groups, but with significant differences among Group III, that presented few alterations, and the other groups; - the central maxillary incisors presented similar behavior in the three groups, during the expansion and retention periods, characterized by the inclination movements and by the root divergence and convergence of the crowns; - analyzing the overbite and the lower anterior facial height variables, it was concluded that the three appliance types showed similar vertical alterations, due to RME.

Keywords: Rapid maxillary expansion. Posterior crossbite. Posteroanterior radiographs. Orthodontics. Cephalometric.

Saturday, December 28, 2024 22:27