two groups of Class III malocclusion patients treated with Haas expander, submitted to two distinct RME protocols.
Method: Twenty individuals, aged 5 to 9 years old, were divided into two groups. Group 1, 10 patients were submitted to seven weeks of alternated rapid maxillary expansions and constrictions, protocol modified of Liou and Tsai (2005), 2/4 turn per Day. In eighth week, it was repeated 2/4 turn per day of expansion, totaling 2 weeks of expansion. Group 2,10 patients were submitted to two weeks of RME screw activation of 2/4 per day. Both group were followed by 24 weeks of maxillary protraction. The evaluation was accomplished through lateral cephalometric radiographies and Cone-beam computerized tomography, in different times: in the beginning of the treatment (T1), after eighth week of alternated expansions and constrictions of maxilla in Group 1 (T2), after two weeks of rapid maxillary expansion in Group 2 (T2) and after 24 weeks of treatment of maxillary protraction (T3) in both groups. The t-student test was used to compare the Groups 1 and 2. The Friedman test was used to compare results at T1, T2 and T3 for both groups.
Result: The results obtained for both groups were similar. The maxilla was displaced slightly forward and downward in a counterclockwise. The mandible rotated downward and backward with an increase of the anterior facial height and the sagittal maxillomandibular relationship with the soft tissue profile and the facial convexity improvement was observed.
Conclusion: Both protocols were efficient in expansion of maxilla with similar results, some results are still missing and will be concluded in this study to assess whether the protocols are really similar of maxillary protraction