Research On The Dynamic Aesthetics Characteristics Of Yunnan Hani Nationality And Han Nationality In Spontaneous Smile

Objective:To explore a method of obtaining the naturally and repeatably spontaneous smile and to analysis the dynamic aesthetics characteristics of lips-teeth-gingivae of Yunnan Hani nationality and Han nationality in spontaneous smile.Methods:50 volunteers were selected randomly to watch and score comedy films. Different comedy films were watched successively and the same comedy film was watched again after one month in order to check the validity of the video. Multi-stage, stratified sampling was used to randomly select 227 subjects of Yunnan Hani nationality and Han nationality, which Hani nationality were 93, Han nationality were 134. It was recorded the facial dynamic characteristics by high definition video recorder when subjects watching the short video clips, and was used to analysis the dynamic aesthetics indicator of lips-teeth-gingivae in spontaneous smile by computer video processing software and image measurement software. Then analyzed the factors of gender, nationality influence on the aesthetic characteristics.Results:(1) There was no statistical difference of the upper central incisor exposure and intercommissural width at the maximum smile between different films and between different times of the same film (P> 0.05). (2) The display of maxillary incisor teeth were more than maxillary lateral incisor and canine whether different nationality or different gender.(3) The gingival exposure of the two nationalities revealed that women were significantly more than males,especially the gingival exposure of female hani nationality is about twice as much as the male. (4) The change of the mouth-lips of Hani and Han nationality subjects from posture to spontaneous smile were:upper lip length shorten by 30%; upper lip thickness reduced byf 35%; intercommissural width increased by 30%.(5) the smile ratio of Hani and Han nationality at spontaneous smile is respectively 4.55,4.70; buccal corridor ratio were 8.6%,10%.(6)The majority subjects of Hani nationality and Han nationality in spontaneous smile are medium and high smile line, but there is a clear national differences, of which 59% of hani samples are high smile lines,60% of the han nationality samples are median line. (7) Han nationality in the spontaneous smile when exposed to a higher proportion of first premolar (58%), and Hani nationality revealed to the higher percentage (61%) of the second premolar.Conclusions:(1) It has been established a reliable method to obtain the spontaneous smile in the minimum interference state, it is a method of combining dynamic recording of the video recorder with analysis and measurement of computer software. (2) It has been obtained the dynamic aesthetics characteristics of lips-teeth-gingivae of Yunnan Hani nationality and Han nationality in spontaneous smile. The dynamic aesthetics database of Yunnan Hani nationality and Han nationality in spontaneous smile has been built up.