Comparação da protração maxilar em pacientes portadores de maloclusão classe III após dois protocolos de expansão rápida da maxila

• Autor(a) principal: Vecchi, Ariadna
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional PUCRS
• Texto Completo: http://hdl.handle.net/10923/448
• topic: ODONTOLOGIA; ORTODONTIA; OCLUSÃO DENTÁRIA; MAXILARES - CIRURGIA; MALOCLUSÃO; MANDÍBULA

The aim of this study was to evaluate and compare two groups of patients with Class III malocclusion treated with Hyrax expander, using different protocols of rapid maxillary expansion associated to reverse pull face mask, using an approximate force of 500g per side, directed 30° downward to the palatal plane, used for at least 14 hours per day. Eighteen individuals, between 7 and 14 years old, were divided into two groups. Group 1 has undergone 7 weeks of alternate rapid maxillary expansions and constrictions protocol, suggested by Liou and Tsai (2005), followed by 17 weeks of maxillary protraction. Group 2 has undergone daily 4/4 of turn activation during 7 days, followed by 23 weeks of maxillary protraction. The total treatment time was 24 weeks for both groups. Lateral cephalometric radiographs were taken before the treatment (T1), after 7 weeks of alternate expansions and constrictions of maxilla, in Group 1 and after 1 week of rapid maxillary expansion, in Group 2 (T2), and at 24 weeks of active treatment (T3). The t-student test was used to compares the Groups 1 and 2. The Friedman test was used to compare results at T1, T2 and T3 for both groups. The results obtained for both groups were similar. According to the results of the present study the maxilla has moved forward and downward. Also the palatal plane has rotated clockwise, in Group 1, and counterclockwise, in Group 2. No mandibular changes were observed. The ANB angle increased, and the maxillary incisors moved forward and downward. Facial convexity has increased. Only in Group 2, inferior facial height has increased and maxillary molars moved downward.