Three-dimensional Photogrammetric Analysis Of Facial Soft Tissue In Young Adults Of Mongols And Han Nationalities

Objective The facial soft tissue morphology of normal adults in Mongols and Han nationality was collected by 3D Stereo photography,and the depth of facial soft tissue was measured on the 3D images,to compare the differences of facial depth between Mongols and Han nationality,and to provide reference data for clinical design of Orthognathic and Orthodontic Treatment,and for cosmetic surgery.Methods A total of 348 subjects with normal BMI,no abnormal facial appearance,no history of orthognathic surgery and no history of facial plastic surgery were recruited from universities in the Inner Mongolia,age range of 20-25 years,there were 70 adult males in Mongols,79 adult females in Mongols,94 Han males,and 105 Han females.The subjects were divided into four groups according to nationality and sex.The soft tissue of the subjects were scanned by Morpheus 3D facial scanner(Morpheus 3D Company,Korea),and 12 items of the depth of the soft tissue of the subjects were measured by three-dimensional images,which were all linear indexes.All the images were taken and measured by the same researcher.33 subjects(6 males in Mongols,7 females in Mongols,9 males and 11 females of Han nationality)were measured repeatedly,the intra-group Correlation Coefficient(ICC)was used to analyze the intra-group error.SPSS 19.0 software was used to analyze the measured data.The differences of facial soft tissue depth between male and Han nationality in Mongols and between female and Han nationality in Mongols were compared by t test.Results The intra-tester error analysis showed that the investigators' measurements of all items were well consistent(ICC > 0.80).Measurements of facial soft tissue depth in Han Chinese were generally greater than those in Mongols,and in Mongols compared with Han Chinese men,there were significant differences in depth of bilateral frontal depth,bilateral supraorbital depth,bilateral upper facial depth,bilateral nasal depth,bilateral middle facial depth,right oral depth and right sublabial depth,bilateral orbital depth,bilateral alinasal depth and bilateral labio depth(p < 0.001),there were differences in the depth of left oral depth,left sublabial depth and right pogonion depth(p < 0.05),but no significant difference in other indexes.In contrast to Han women in Mongols,there were significant differences in depth of bilateral frontal,right supraorbital,bilateral upper facial depth depth,depth of right nasal,depth of right middle facial depth,depth of right oral depth,depth of right sublabial depth,depth of bilateral oral depth,depth of right alinassal depth,depth of right labio and depth of right pogonion depth(p < 0.001),the depth of left supraorbital,left upper facial depth,left nasal depth,left middle facial depth,left oral depth,left sublabial depth,right lower facial depth,left labio depth were statistically significant(p < 0.05),the rest were not statistically significant.There were significant differences in 12 soft tissue depth indexes between male and female(p < 0.001).Conclusion This study compared the depth of facial soft tissue between adults of Mongols and Han nationality to determine the differences in facial morphology.in particular,there were significant differences in frontal,nasal,orbital and maxillary depth,which were distributed on the face and in the middle third of the face.The Han nationality's measured values were higher than those of the Mongols,it is suggested that the facial features of Han nationality are more stereoscopic than those of Mongols,especially on the forehead,nose and the middle third of the face.In the comparison between male and female,the measurement value of male was larger than that of female,and there was a significant difference(p < 0.001),which suggested that the stereoscopic sense of male face was stronger.It can provide quantitative reference for facial reconstruction,restoration,design of orthognathic treatment,injection and filling of facial micro-plastic injection At the same time,the three-dimensional Stereo photography has many advantages,such as high speed,high accuracy,non-harmfulness.