The Research Of The Directory Of Clinical Orthodontic Extraction With Extraction Index EI

Objective:To explore the significance of EI the clinic application, it was compared the relativity between the extraction index (EI) and practical extraction in the teenagers when treating the cases of classâ… ,classâ…¡, and classâ…¢malocclusion, in order to find out the diferences between slight congestion group and congestion group,male group and female group, classâ… malocclusion group classâ…¡malocclusion group and classâ…¢malocclusion group.Methods: Data were obtained from 141 cases after successful treatment with malocclusion. The age is 12~18 years old. Masculine patient 57 examples,feminine patient 84 examples. Dividing the patients into slight congestion group and congestion group;Categorizing the patients into classâ… , classâ…¡,and classâ…¢by Angle malocclusion method;further more, dividing each group into the slight congestion group and congestion group. Analyzing the function of congestion factor between the groups,and doing the retrospective test of EI at the same time.Results: Precision predicting to all exponent is 74.17% using extraction index EI . The EI forecast is consistent in the young people masculine patient group rate is 81.63%. In the young people feminine group is 69.01%. A ccording to the malocclusion type classification,the total unanimous rate is 75.00% in Angleâ… cases,80.00% in Angleâ…¡cases,69.50% in Angleâ…¢cases. But the slight congestion group and the congestion group consistent rate contrast existence significant difference in Angleâ…¢cases. In the total sample EI forecast to 54 examples crowded case of illnessis consistent rate is 64.81%, But is consistent to 66 examples mild crowded case of illness forecast rate is 81.82%, The crowded group has significantdifference with the mild crowded group. In the EI predicting extraction group,There is no different significance of the practical extraction between congestion group and slight congestion group(p>0.05); In the EI predicting non-extraction group, There is significant diference of the practical extraction between congestion group and slight congestion group(p<0.05).Conclusion: The extraction index EI has some guidances in the strategy of malocclusion design whether in diferent congestion group or in diferent Angel classes. Classifies patient EI to Angle's malocclusion the effect is same. But in each group, The slight congestion group is consistent rate always is bigger than congestion group. However, the higher rate in slight congestion group than in congestion group suggests that extraction index EI has neglected the factor of congestion in the clinic decision to extract or not. Thus, it should be analyzed the congestion of model to make a decision.