Comparação dos efeitos do aparelho extrabucal com tração combinada, com e sem expansão rápida maxilar para tratamento da Classe II, Divisão 1

Abstract

The aim of this study was to verify the effects of headgear with combined traction used alone or associated with rapid maxillary expansion on the upper molars, maxilla, mandible and maxillomandibular anteroposterior relationship, as the first step of treatment of Class II malocclusion. The sample comprised 61 patients divided into 3 groups: Group 1, headgear combined traction (CH); Group 2, CH + rapid maxillary expansion (CH + RME); and Group 3, control (CG). In Group 1, patients were treated by headgear with combined traction until a Class I molar relationship was reached. In Group 2, the protocol for headgear was the same; however, the patients received rapid maxillary expansion previously. The results showed distal displacement of molars for both experimental groups (P < 0.001), with distal inclination only in Group 1 (CH) (P < 0.001). There was restriction of the forward growth of the maxilla in Group 2 (CH + RME) (P <0 .05) and clockwise rotation of the maxilla in Group 1 (CH) (P < 0.05). Mandibular projection was observed between T1 and T2 in group 2 (P < 0.05), but no significant difference was found between the other groups (P > 0.05). The maxillomandibular relationship improved in both experimental groups (P < 0.01); however, the variation was greater in group 2 (P < 0.05). Considering the results, it is possible to conclude that the treatment with both protocols was efficient; however, the results were more significant for Group 2 (CH + RME), with shorter treatment time and with less collateral effects.