| Bimaxillary Protrusion is one of the familiar malocclusion.It often occurs in Asian, espeacially in Guangdong province. Skeletal Bimaxillary Protrusion patients often have distinct mandibular and maxillary bone protrusion, which badly effect his profile and mastication function. Furthermore, it can effect the mentality to the extent. Because of these reasons, they insist on orthodontically treating the abnormality to improve profile. At present, there are two main methods for treating severe skeletal bimaxillary protrusion: the first is orthidoontic extraction. By closing space to retract anterior teeth, it can resolve the problem of protrusion. The second method is combining orthognathic and orthodontical treatment. By orthodontical treatment before the surgery, teeth are aligned. When we do the surgery, four premolars are extracted., and upper and lower jaws of the subapical osteotomy are performed. Canine -canine segmental alveolar bone are retruded in order to improve profile. There are different viewpoints to the advantages and disadvantages of the two methods. In our study, we applyed these two methods: orthodontics combined with orthognathia and orthodontic treatment only. By observing the changes of hard and soft tissue of bimaxillary protrusion patients, we compared the advantages with disadvantages of these two methods in order to offer theory for clinical orthodontic treatment, including the selection of indications and effective orthodontic methods, and the index for evaluation.In our study, bimaxillary protrusion patients were divided into two groups :treated by orthodontics combined with orthognathia andorthodontic treatment only. We observed facial profile changes before and after treatment.The changes were evaluated by the measurement of facial profile esthetic index.We compared the effects of the treatments with standard facial profile esthetic indexs of Chinese. The results were as follows:1. Evaluating the effects of orthodontic method by treating 12 adult skeletal bimaxillary protrusion patients. They would not accept the surgery, so we applyed routine orthodontic treatments. Four fist premolars were extracted and closed space by retracting anterior teeth, the problem of protrusion was patially resolved. We compared the changes of 15 soft tissue and hard tissue index before and after the treatment. Furthermore,we calculated the value of Y by profile esthetics formula. The result was that 10 soft tissue and hard tissue index had changed to normal index after the theatment. However, five index, including the SNA, SNB, FMA, A'Ls-FH and G-SN-Pg', did not changed evidently. 8 patients' value of Y were less than 0 after the treatment. Their profile was improved. However, 4 patients' value of Y were still more than 0, the changes of their profiles were not satisfied. The average treatment time was 27. 6 months.2. Evaluating the effect of subapical osteotomy for treating 12 adult skeletal bimaxillary protrusion patients. We applyed orthognathia combined with orthodontic treatment. Teeth were aligned and eliminated the compensation by presurgery orthodontic treatment. And the subapical osteotomy was performed. Canine-canine segmental alveolar were retruded in order to improve the facial. At last, teeth were adjusted by posturgery orthodontic treatment. We compared the changes of 15 soft and hard tissue index and the value of Y beforeand after the treatment. Result:15soft and hard tissue index were changed to the normal range, excluding FMA, which often did not change. 11 patients' value of Y were less than 0 after the treatment.they had reached the standard of satisfied profile. The average time of treatment was 8.9 months. Conclusion: Combined applying orthognathia and orthodontic treatment is an effective method for moderate and severe adult bimaxillary protrusion patients. The advantages are as follows :1. The period is the shorter than orthodontic treatment only.2. The extraction space is utilized sufficiently. 3. Anchorage teeth is stable At the same time, the vertical malfor... |
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