[The clinical study of protraction face mask combining with MEAW technique to correct skeletal Class III malocclusion in the early permanent tooth].

PURPOSE: To investigate the clinical effects of combined multiloop Edgewise arch wire(MEAW) with protraction facemask to treat Class III malocclusion in early permanent dentition, and compare the changes of the periodental tissue and teeth between pre- and post- treatment to explore the mechenism of the method applied to correct Class III malocclusion. METHODS: 23 cases with Class III malocclusion were selected, including 11 males and 12 females, aged from 12 to 14 years old. MEAW and protraction facemask were used to treat Class III malocclusion in early permanent dentition. Lateral cephalometric films were taken for comparison in three stages:before the treatment(T1), seven months (T2) after treatment and in the end of the treatment(T3).SPSS10.0 software package was used for statistical analysis. RESULTS: The alveolar bone changes mainly happaned in the T2 stage, SNA increased by 2.37 degrees in average, OP-MP increased by 4.85 degrees in average; Wits increased by 2. 50 degrees in average. The difference was significant(P<0.05). However there was no significant difference between T2 and T3 stage. In the T2 stage,the overjet and overbite increased 4.43mm and 2.66mm in average, and increase continued after treatment. CONCLUSION: It is suggested that MEAW with protraction facemask is an effective technique to treat Class III malocclusion in early permanent dentition by improving maxillary growth.