A Meta-analysis:The Effect Of Extraction Treatment On Soft Tissue Profile In Borderline Cases

Objective:The aim of this study is to search for the best evidence for the effect of tooth extraction on the soft tissue profile through meta-analysis in borderline cases,and to find deficiencies in existing evidence by bias analysis,thus providing a theoretical reference for improving the evidence.Methods:Literatures were collected concerning comparison of soft tissue profile changes after extraction and non-extraction orthodontic treatment.“Extractions”,“nonextractions”,“soft tissue profile”,“malocclusion”,“orthodontics”etc.were searched in online Databases such as Cochrane library,Web of knowledge,Pubmed,CNKI and Wanfang.Manual searching and literature trace-back were also applied to obtain further information.High quality studies were selected according to inclusion and exclusion criteria.Quality evaluation of the included studies was conducted based on Cochrane Collaborative Network bias evaluation risk assessment criteria.Statistical techniques of meta-analysis were used to comprehensively analyze the soft tissue indicators before and after orthodontic treatment in extraction and non-extraction treatment in borderline cases.Based on the heterogeneity test results,a fixed effect model or a stochastic effect model was used to calculate mean difference of the combined statistics and their 95%confidence interval in Revman5.3.Result:Ten studies were included in this study.Heterogeneity test showed that the heterogeneities of NLE,MLE,UL-E,LL-E,UL-S,and LL-E were acceptable(I~2<50%),so fixed effect model was adopted.The heterogeneity of G-Sn-Pos was more than 50%,so random effect model was adopted.Meta-analysis results showed that the mean difference of combined statisticsof NLE,UL-E,LL-E,UL-S,and LL-E changes between extraction group and non-extraction group,and their 95%CI,were statistically significant.Conclusion:Compared with non-extraction treatment,the protrusion degree of upper and lower lips decreased and the nasolabial angle increased to some extent after extraction treatment.Two intervention methods had no difference in changes in chin-lip angle.The existing research is insufficient,there for,strictedly designed original researches in accordance with the standard for evidence-based medicine research are required to provide reliable evidence for clinical practice.