The Effect Of Protraction For Skeletal Class Ⅲ Malocclusion At Various Time:a Meta-analysis

ObjectiveAccording to the method of Meta analysis,the patients with skeletal Class Ⅲmalocclusion were grouped according to the timing of correction,and the data were extracted for statistical analysis to evaluate the premaxillary premaxillary group,the growth peak group,and the post growth peak group.The clinical effect of traction and correction provides a certain reference for patients with skeletal Class Ⅲmalocclusion in the field of clinical diagnosis and treatment of the timing of correction.MethodBased on the research methods of evidence-based medicine,this article uses computers to search PubMed,Cochrane and other professional knowledge comprehensive service platform,etc,collect relevant upper jaw Domestic and foreign literature on the timing of anterior traction correction（as of November 31,2020）.The two scholars strictly implemented the determined inclusion and exclusion criteria and data information of the relevant trials,and then carried out the methodological quality assessment.According to RevMan 5.4,the characteristic data information of the documents containing the same parameters were extracted,and the data information was quantitatively analyzed using Meta analysis.On this basis,forest maps were made to test their heterogeneity.The weighted average difference（WMD）is based on the heterogeneous data information,one by one selection and matching effect mode,and finally merge.In addition,a descriptive analysis of the data that cannot be used for forest map statistics due to different corresponding indicators describing the results.ResultMeta-analysis data confirmed that according to the classification of deciduous dentition,mixed dentition group and permanent dentition group,there is not much difference in the efficacy of early and late traction treatment.According to the grouping of bone age,it can be concluded that the treatment effect during the peak growth period and the pre-peak growth period is similar,more bone reconstruction can be obtained,and less tooth compensation can be obtained,which are better than those after the peak growth period.The heterogeneity of scientific research based on cervical spine bone age grouping is much smaller than that of research based on dental age grouping.ConclusionBone age can be used as a key evaluation index for the timing of anterior traction and correction.For patients with skeletal Class Ⅲ malocclusion at the peak of growth,differentiation and development,anterior traction treatment can produce more bony effects and less dental compensation.For patients after the peak,the skeletal effect is reduced and the dental compensation increases.Therefore,the best period for anterior traction treatment should be before or during the peak period of growth,differentiation and development,and the curative effect obtained at this time is better.In addition,women develop earlier than men,and individual differences are greater.Clinically,we can observe the stages of cervical spine bone age based on X-ray lateral radiographs to determine the stage of growth,differentiation,and development of patients,and choose the right time for anterior traction correction.