Correlation Research On Facial Soft-tissue Profile Esthetic Indexes And Facial Esthetics Evaluation

Objective:The objective of this study is to investigate possible aesthetic indexes affect the attractiveness of the soft-tissue profiles between laypersons and orthodontists in Liaoning province.We aimed to provide the esthetic reference values for orthodontic treatment.Materials and methods:According to the inclusive criteria,a total of 30 cases(female,ranging from 18 to 30,average 24 ±2.7 years old),which are all individual normal jaw in Liaoning province,were included in this study.All selected subjects'cranio-maxillofacial regions were scanned with CBCT and the data acquired will be imported to and reconstructed the Invivo5.0 software.The lateral cephalometric radiographs were created from 3D virtual models.Then take lateral profile of the subjects,during which time the subjects should seat in natural head posture.Import the lateral cephalometric radiographs and profile photographs into Adobe Photoshop CS6.Edit lateral cephalometric radiographs,such as,rotate,zoom in,and move,so that they could overlap with profile photographs in natural head posture.Then we get lateral cephalometric radiographs in naturall head posture.Making profile silhouettes with these pictures in Adobe Photoshop CS6.85 laypersons and 29 orthodontists was invited to evaluate the attractiveness of this 30 profile silhouettes.Data collection will be achieved by questionnaire with 5-point Likert scale for rating.Edit personal measurement and analysis program with WinCeph8.0,and use it to measure every kind of facial soft tissue from the aspect of aesthetic indexes for lateral cephalometric radiographs in natural head posture.After all measured and rated data has been verified,it should be logged in Microsoft Excel 2007 and establish a database.Statistical analysis of data in this study are finished by adopting SPSS22.0 software.Paired t-tests were carried out for measured value of aesthetic indexes from two groups with measuring error examined.Average the score in each group for every silhouette.Then by executing paired t-tests,compare the average score of two groups to determine whether there are statistical differences.Then use Pearson correlation analysis to each silhouette score and measured values of aesthetic indexes to find out the soft tissue aesthetic indexes which related to aesthetics evaluation.Take the soft tissue aesthetic indexes as the independent variable,two groups of score value as the dependent variable,make multiple linear stepwise regression analysis respectively and obtain the regression equation.All statistical method inspection standard are a = 0.05.Results:Orthodontists group has on average 0.05 points higher than laypersons.The aesthetic evaluation difference between orthodontists and laypersons is of statistical significance.Pearson correlation analysis results show that the influence of both orthodontists and the laypersons aesthetic evaluation of soft tissue measurements are TLL-TVL,B'-TVL,Pos-TVL.After the multi-factor stepwise linear regression analysis we obtained two regression equations.The score of orthodontists group is Y1=1,949-0.068×X1+0.236×X2+0.115×X3.the score of laypersons group is Y2=2.055-0.080×X1+0.178×X2+0.070xX3.Rating results are is of negative correlation with TLL-TVL,and of positive correlation with B'-TVL,Pos-TVL,among which the maximum absolute value of correlation coefficient is from B'-TVL.The trend in two groups are consistent as the change of independent variable.And the point B' is also the most influential factor on the scores.Conclusions:According to the result of this study,there are statistical differences between orthodontists and laypersons in soft tissue profile esthetic indexes,in which the orthodontists has marginally higher scores and dispersions.This resultsuggests that the orthodontists have clearer concept and preferences of esthetic indexes in soft tissue profiles than the laypersons,whose scores are mainly distributed in the middle stage.The value of TLL-TVL,B'-TVL and Pos-TVL are three key soft-tissue measurements that influence the esthetic indexes both for orthodontists and laypersons.These three measurements are correlated to the real vertical line in natural head position,which indicates that the head position is an element that attributes to the esthetic indexes in soft tissue profiles.The head position should also be considered when the relative nose-lip-chin position is studied in the soft tissue profile esthetics.According to the regression equation concluded from this paper,in both group of the orthodontists and laypersons,the value of TLL-TVL is negative to the score,while the value of B'-TVL and Pos-TV is positive to the score.The value of B'-TVL attributes greatest to the esthetic indexes.This conclusion implies that in certain value ranges,the orthodontists and laypersons equally prefer the profile of relatively shrank lower lip and protruding soft tissue chin in natural head position.The distance between point B' and the vertical line in natural head position should be seriously studied.The regression equation in the study can be used to compare the profile esthetics before and after the orthodontics and the scores before orthodontics can be references in clinical orthodontic scheme.