The Effects Of Quick Self-ligating System On Elarging Maxillary And Alveolar Arch

[Objective] The aim of this study was to analyze the effects of Quick self-ligating bracket on enlarging the maxillary alveolar arch, discussing the key index and the relative enlarged arch of Quick self-ligating bracket on expending alveolar arch by means of models and cephalometric radiographs, to investigate the basic and precise theory for the orthodontist in order to make a plan fordeveloping the non-extraction treatment programs.[Method] Randomly selected 60 patients who were used Quick self-ligating bracketappliance for treatment from Orthodontics department of affiliated Stomatology Hospital of Kunming Medical University, aged from 10 to 16 years, mean 12.8 years old. The maxillary dentition was flatted and smoothed by the heat activated nickel-titanium wire (FeiFan Company, German), then assessed by occlusalplane analysis method. The maxillary model and cephalometric radiographs were collected and measured before and after treatment.Statistical analysis was done by SPSS20.0 statistical software using a t-test, Pearson correlation coefficient analysis, Spearman correlation coefficient analysis, multiple regression method for data analysis and modeling.[Result] 1.According to the statistic test,to varying degrees, all the non-extraction patients had a statistically significant (p<0.01) enlarged on their maxillary alveolar after they were treated by Quick self-ligating bracket appliance. 2.The variation of angle of anterior teeth was increased gradually with the increase of ∠ANB and the crowding degree of arch; Besides, increasing ∠FMA and crowding degree would lead to the variation inpremolar teeth. At the same time, the arch length showed an upward trend which was grew with the increase of ∠ANB and the crowding degree of arch, whereas it saw a fall with the increase of the angle of anterior teeth. Class Ⅲ variation relaed parts changes are obvious. When canines wih initial lip position, arch length changes significantly. Whill the second molar eruption or not, the first premolar has clear width variation,whether first molar has little changes.3.Formula can predict the location which expansive most obvious and the variation.[Conclusion] The crowding degree of arch, ∠FMA, ∠ANB, the angle of the anterior teeth, malocclusion classification, canines initial position, he second molar eruption or not, were essential factors affecting the result of non-extraction Quick self-lagating bracket appliance treatment on enlarging the maxillary alveolar. The Prediction formula may provide a reference for the development of future appliance treatment. Formula can predict the location which expansive most obvious and the variation.