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Objective : Through the Adult Class Ⅲ low-angle cases extraction treatment , investigate standard edgewise technique extraction treatment efficacy , as well as soft tissue and cephalometric improve the situation. Materials and Methods: Dalian Ortho Dental Clinic in July 2009 admitted to Class Ⅲ malocclusion patients one case , male, aged 22 years, 5 months , mandibular protrusion, molar and canine relationship is completely mesial , anterior occlusal anti repeatedly covered up and down crowding , maxillary midline left side, right side mandibular midline . Through the analysis of the patient's model , cephalometric analysis, subtrahend unplug the mandibular first premolars and third molars , using the standard edgewise technique correction . In the week before and after treatment uptake cephalometric X-ray film , select Tweed, MEAW, Beijing University and other analysis of the measurements , a total of 25 were observed before and after treatment changes. Results: The treatment course of 20 months. The analysis and comparison of before and after treatment : molar relationship becomes neutral by the relationship between class Ⅲ , Ⅲ type facial type is improved ; SNA has not changed , SNB reduced 2 °, ANB increased 2 °, AO-BO increased 3.5 mm; mandibular clockwise increases the mandibular plane angle (FMA by the 17 ° increased to 19 °, Po-NB by a 2.5mm reduced to 1.5mm); cutting teeth on the shaft changed little , the lower incisors vertical (IMPA by the 102 ° less as small as 88 °), the upper and lower midline alignment ; soft tissue profile improved , Li-E decreases 4mm. Treatment of patients and parents satisfied with the results . Conclusion: Class Ⅲ malocclusion adult patients with low-angle , tooth extraction , using edgewise technique , combined with early treatment class Ⅲ traction control in three dimensions the movement of the teeth , increasing the mandibular plane angle , correct molar and canine relationship , anterior overbite coverage and improving the soft tissue profile were obtained satisfactory results .
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