Study Of The Relationship Between Facial Feature And Occlusal Vertical Dimension & Maxillary Anterior Teeth Position For The Normal Occlusion Human

Object To study the relationship between facial feature and occlusal vertical dimension ( OVD ) and maxillary anterior teeth position for the normal occlusion human to provide guidances for clinically identifying occlusal vertical dimension and maxillary anterior teeth arrangement.Methods (1) According to the inclusion criteria of the normal occlusion human, screen 125 normal subjects from the Grade 2004-2006 undergraduate students in Fujian Medical University, 55 men and 70 women. (2) Direct Measurement Method: Use centrometer to measure the interpupillary distance (IPD) of the subjects, and use the vertical distance measurement device and digital vernier caliper to measure their OVD and the the eye to ear distance.(3)Indirect Measurement Meathod: Photographs the front image of mandibular postural position(MPP) by the use of digital cameras in a unified standard and the side image of intercuspal position(ICP) as well as the ICP front image of the exposed upper front teeth. Then transmit the image to a computer, using image measurement software to measure the innercanthal distance(ICD), the outercanthal distance(OCD), IPD, ICD to the side of OCD, eyes width, interalar width, intercommissural width(ICm), OVD, width of maxillary six anterior teeth and distance between the tips of upper canines. (4) Respectively apply statistical methods such as the two-sample t-test, single-factor analysis of variance, linear regression and correlation ,and multiple linear regression and regression and so on to statistically analyze the experimental results.Result (1) In the use of the direct measurement method, the relevant occlusion between the IPD and the OVD is strongest----mean total of the IPD is 63.98±3.26 mm, for men 65.46±2.96 mm and for women 62.86±3.05 mm; mean total of the OVD is 65.35±4.70mm, 68.16±4.23mm for men, women 63.22±3.86 mm; respectively, the correlation coefficient is r total = 0.633, r male = 0.563, r female = 0.531.(2) In the digital photos, the relevant occlusion between the middle 1/3 height of the face and OVD is strongest , in which the left side of the middle 1/3 height of the face is 67.33±4.15 mm, for men 69.70±3.98 mm, and for women 65.53±3.31 mm; The correlation coefficients are r total = 0.619, r male = 0.616 and r female = 0.354 respectively. In the right side of the middle 1/3 height of the face , the average height is 68.07±4.09mm, 70.60±3.79mm for men, 66.16±3.19mm for women, and the correlation coefficients between occlusal vertical distance and the middle 1/3 height of the face are r total = 0.618, = r male 0.645 and r female = 0.292 respectively; mean total of the OVD is 61.79±4.37mm, 64.38±4.02mm for men, 59.83±3.53mm for women. (3) In the digital photos, the relevant occlusion between the male IPD and width of maxillary six anterior teeth is the strongest correlation, r = 0.618, and the male ICD and the distance between the tips of upper canines is most relevant , r = 0.599; in different arch type, however, the IPD and width of maxillary six anterior teeth of square-round type is the strongest correlation, r = 0.627, and the IPD and the distance between the tips of upper canines of the oval type is the strongest, r = 0.568. (4)Under multipling linear regression analysis to the ICD,the OCD, Intercommissur- al width, Interalar Width, the IPD and the different arch types and width of maxillary six anterior teeth and distance between the tips of upper canines of the men and women,we obtain the multiple correlation coefficient, respectively r1=0.660, r2 = 0.614.Conclusion (1) The results showed in the direct method that the IPD and the OVD of the Fujian normal occlusion youths was significantly correlated, and the IPD can be defined as the reference for clinically identifying the OVD .However, there is no significant correlation between the Fujian normal occlusion youths'eye to ear distance and the OVD. Therefore, it's of little clinical significance. (2) Indirect method (digital photos measuring method) showed that the middle 1/3 height of the face, the OCD and the OVD was significantly correlated, and the middle 1/3 height of the face can be identified as a clinical reference of the OVD . (3)The indirect method (digital photos measuring method) showed that, regardless of the breakdown by sex or the type of arch, the IPD, the ICD ,the OCD are significant inter-related with the width of maxillary six anterior teeth and distance between the tips of upper canines. Hence, the IPD, the ICD ,the OCD can be used as a reference indicator for arranging maxillary anterior teeth.(4) Multiple regression analysis showed that taking the joint sex, arch type, the IPD, the ICD ,the OCD, interalar width and intercommissural width of the common factors as maxillary anterior teeth arrangem- ent forecast can improve the accuracy of forecast .