Retrospective Study On Soft Tissue Profile Of Borderline Malocclusions With Extraction And Nonextraction Treatment

Objective:The aim of this study is to determine whether there are systematic morphologic differences of the dentofacial relationships between the cases of extraction treatment group and the non-extraction treatment group through retrospective study of related literatures about borderline cases.Methods:A literature search was conducted to identify clinical trials that assessedcephalometric soft tissue changes in patients affected by extraction or nonextraction treatment in Angle class II and class II borderline malocclusions. According to the type of malocclusions,these literatures were divided into two groups.(Class I malocclusion group and class II malocclusion group.) Basic information and the characteristic of malocclusions were selected to show according to the literatures.The morphologic features and differences between extraction and non-extraction treatment groups were analysis.Results:The result of the present study indicated that compared with the nonextraction cases, the extraction cases of class I malocclusions, have bigger crowding, higher degree of U1-NA and L1-NB,and more distance of upper and lower lip to E-line as well as smaller nasolabial angle before treatmet.The extraction cases of class II malocclusions have larger ANB angle, and higher MP-FH angle,the distance of upper and lower lips to E line in male,and the distance of lower lip to E line in female were longer than that of the nonextractino cases, the nasolabial angle smaller than that of the non-extraction cases.Conclusions:There are some differences in the dentofacial morphology between the borderline cases of extraction and non-extraction treatment groups, which will contribut to design the treatment plan for borderline cases. Objective:To evaluate the effect of extraction four first premolar treatment on the soft tissue profile of Angle class Ⅱ.division1malocclusion.Methods:I get through searching Electronic databases(The Cochrane library(2014,Issue:2),web of knowledge(1950-2014.2), PubMed(1949-2014.2),Embase(1974-2014.2),CBM(1978-2014.2), V IP(1989-2014.2),CNKI(1994-2014.2),wanfang database(1998-2014.2).On the basis of selection criteria,I gathering and analyzing data.We also searched some Paper version of the magazines. Chinese Journal of Stomatology and relevant conference papers were hand searched. The article about evaluating the outcome of extraction four first premolar treatment on the soft tissue profile of Angle class Ⅱ,divisionl malocclusion were considered. The article collected using systematic review network recommended standards for quality evaluation. The meta-analysis conducted by the relevant software.ResuIts:There is only one article that fulfilled the final selection criteria of this systematic review.The sample consisted of31patients.(16patients treated with extraction of four first permanent molars,15patients treated with nonextraction therapy) The result of meta-analysis revealed a significant decrease on U1-NA(degree),U1-NA(mm),L1-NB(mm)(P<0.05) of the patients treated with four first premolars extraction,compared with the nonextraction patients. The data of Nasolabial angle,labrale superioris-E line, labrale inferioris-E line had a significant increase(P<0.05).Besides, the data of SNB angle,ANB angle,Overbite,Overjet,Ll-NB(degree), labiomental angle didn’t show statistically significance between two groups (p>0.05).Conclusions:Compared with the non-extraction cases, the patients of Class Ⅱ, Division1malocclusion with four first premolar extractions showed that the convex of the upper and lower incisors significantly increase the distance of upper and lower lip-esthetic line significantly decrease,and the nasolabial angle increase.The effect of orthodontic treatment on skeletal relationships,overbite,overjet and soft tissue chin are non-obvious.However, small number of subjects, and the method level was low, to deal with a rational view of the conclusions of this study. More randomized controlled trials are required to analysis the effect of four first premolar extraction and nonextraction treatments on the soft tissue profile of Angle class Ⅱ,divisionl malocclusions.