摘要：OBJECTIVE: To evaluate the effects of face mask therapy (RH) on middle cranial base and maxillo-mandibular complexes, and to compare the responses with untreated class 3 subjects. MATERIALS AND METHOD: The treatment group comprised 20 skeletal class 3 children (14 girls, 6 boys; mean age: 11 years 3 months) treated with RH assisted by rapid maxillary expansion (mean treatment time: 9.6 months). The control group included 22 skeletal class 3 subjects (9 girls, 13 boys; mean age: 10 years) observed for 9.5 months. Cephalometric measurements were performed by counterpart analysis. For intragroup statistical comparisons paired t-test, and for intergroup comparisons independent t-test was used. RESULTS: The treatment group revealed significant increases for SNA, ANB, SN-GoGn, Co-A and Co-Gn (p<0.001), and decrease for SNB (p<0.001). The treatment group revealed significant increases in the effective dimension of the middle cranial base (Ar-SE, p<0.05; So-Hor, p<0.001), maxilla (p<0.001), and anterior-posterior nasomaxillary complex (p<0.001, p<0.05, respectively), and decrease in the effective dimension of the mandibular corpus (p<0.05). According to the intergroup comparisons, treatment group revealed more pronounced maxillary advancement (p<0.001), posterior rotation in the mandible (p<0.001), significant increase in the effective dimension of the middle cranial base (So-Hor, p<0.01) and decrease in the effective dimension of the mandibular corpus at a significance level of p<0.001. CONCLUSION: Revealed by the effects on the middle cranial base morphology, favorable treatment responses were achieved with the use of the RH technique.
