Observation Of Long-Term Therapeutic Effects Of The Correction Of Class â…¢ Malocclusion With Maxillary Protraction In Mixed Dentition

Objective The purpose of this study was to analyze and compare the changes of skeletal, dental and soft tissue contributing to the correction of Class â…¢ malocclusion with maxillary protraction and rapid maxillary expansion in the mixed dentition of aged from 7 to 11 years.Methods 28 patients with Class â…¢ malocclusion of 7-11 years in mixed dentition were treated with RME for 1 week and maxillary protraction for 6 months. Lateral cephalometric films taken at the beginning(T0), the end of treatment(T1) and 5 years after the active treatment(T2), were analyzed with Pancherz analysis and SPSS11.0 statistical software.Results After active treatment, the maxilla complex moved forward, the mandible exhibited a downward and backward rotation andthe relationship between the jaws improved significantly. The anterior boundary of the maxillary complex ( A, ANS ) obviously moved forward. The maxillary molars moved mestally and the mandibulary molars moved distally resulted in significant changes of molar relationship. anterior low facial height and the ratio increased. The overjet was corrected by anterior displacement of upper incisors and posterior displacement of the lower incisors. The soft tissue facial profile also improved obviously.Five years after active treatment, while the maxilla moving forward continuously, the mandible grew forward more rapidly. B point and Pog point moved forward obviously. SNB angle increased. ANB angle and NA-PA angle decreased. The relationship between the jaws showed a tendency to replase.To compare with before treatment, at the time of 5 years after active treatment, the maxilla and the mandible had grown forward and downward obviously. The anterior boundary of the maxilla ( A, ANS ) and mandible ( B, Pog )obviously moved forward. The overjet was corrected by anterior displacement of upper incisors and posterior displacement of the lower incisors. The molar relationship was corrected. The soft tissue facial profile improved obviously.Conclusion 1. Combined RME and maxillary protraction was an effective method to treat Class â…¢ malocclusion in mixed dentition.Sagittal correction of Class HI malocclusion was primarily a result of forward and downward movement of the maxilla and clockwise rotation of the mandible. Labial tipping of the upper insiors and lingual tipping of the lower insiors, overjeU overbite and molar relationship had significant changes. The soft facial pofile also improved obviously. 2. After active treatment, while the maxilla moving forward continuously, the mandible grew forward more rapidly. The relationship between the jaws showed a tendency to replase. 3. To compare with before treatment, at the time of 5 years after active treatment, the maxilla and the mandible had grown forward and downward obviously. The overjet and molar relationship was corrected. The soft tissue facial profile improved obviously.