Clinical Research Of The Effect Of Arch Expansion Using SmartClip^TM Self-ligation Appliance

Development of appliance is an important driving force to promote the development of orthodontic. With the development of appliance and appliance technology, because of the advantages of preservation of teeth in orthodontic clinical, non-extraction orthodontic treatment gradually occupies the position and can not be ignored. With its low-friction, not neutered, shorten the operation time and duration, self-ligation appliance are gradually more and more concerned by orthodontic doctors. Especially in recent years, Dr. Damon point the effect of arch expansion using self-liagtion appliance, has opened new avenues of non-extraction orthodontic treatment.Crowding is the most common malocclusion, an incidence rate of 60% -70%. The treatment principle of crowding is to reduce tooth and (or) increased bone mass. Expanding the dental arch is a common means to correct moderate crowding, the method of arch width expansion include orthopedic expansion, orthodontic expansion and functional expansion. Dr. Damon said that during the course of treatment, Damon self-ligation appliance can provide the power that close to the optimal light force to achieve arch expansion. However, there have not yet seen the long-term research results about the stability of the self-ligation expansion effect and the mechanism of the dental arch expansion are also more controversial. There is no report about the effect of arch expansion using SmartClipTM self-ligation appliance now.Objective The purpose of this study is to study the effect of arch expansion using SmartClipTM self-ligation appliance through model analysis and clinical observations on the cases of non-extraction, and compare with MBT straight wire appliance. To explore the mechanism of arch expansion using SmartClipTM self-ligation appliance.Materials and Methods Patients with non-extraction orthodontic treatment and opt SmartClipTM self-ligation appliance for voluntary in 18 cases, as SmartClipTM group, and patients with non-extraction orthodontic treatment and opt MBT straight wire appliance for voluntary in 18 cases, as MBT group. Get the model of treatment in newly diagnosed patients and the model of four phase within 1 month, 3 months, 6 months and 12-month. Measuring the width of maxillary arch, the length of maxillary arch and the width and length of maxillary alveolar arch, and then calculated the difference at various stages of the model data and initial model, then compare the difference between the two sets of appliance. Measurement the data obtained by using the statistical software spss13.0, and t- test statistical analysis.Results 1 month after treatment, compared with the MBT group, the effect of the expansion of posterior width of maxillary arch, the mid-length of maxillary and the length of maxillary alveolar arch are different in SmartClipTM Group (P <0.05). 3 months after treatment, the expansion of preceding arch width and preceding length of maxillary arch in SmartClipTM group was more significant than the MBT group (P <0.05).6 months after treatment, compared with the MBT group, the expansion effect of the preceding width of maxillary arch, the length of maxillary alveolar arch are differences in SmartClipTM Group (P <0.05).12 months after treatment, the results of expansion effect of the preceding width of maxillary arch, the prevceding length of maxillary arch as well as the length and width of maxillary alveolar arch in SmartClipTM group and the MBT group were significantly different (P <0.05), from the third month after treatment, the expansion of preceding width of maxillary arch and the preceding length of maxillary arch in SmartClipTM group has been more significant than the MBT group (P <0.05), from the first month after treatment, the expansion of the length of maxillary alveolar arch in SmartClipTM group has been more significant than the MBT group (P <0.05). During 1 to 6 months, the expansion of the width of the maxillary alveolar arch have no significant difference between the MBT group and SmartClipTM group. During 1 to 6 months, changes of preceding width of maxillary arch are declining, and changes of preceding width of maxillary arch shown a slight increase after 6 month; after 6 month, the changes of preceding length of maxillary arch and the length of maxillary alveolar arch was significantly decreasing; after 1 month, the changes of maxillary alveolar arch width was increasing.Conclusion 1, Both the SmartClipTM self-ligation appliance and MBT straight wire appliance have the effect of the expansion of dental arch. 2, After 6 month, the changes of preceding length of maxillary arch and the length of maxillary alveolar arch was significantly decreasing in both SmartClipTM group and MBT group. 3, Compare with the MBT straight wire appliance, expansion of the preceding width of the maxillary arch, preceding length of maxillary arch and the length of maxillary alveolar arch, the width of alveolar arch in SmartClipTM self-ligation appliance is significantly different; and the effect of expansion on the preceding width of the maxillary arch, preceding length of maxillary arch and the length of maxillary alveolar arch, the width of alveolar arch are shown at different periods of time.