Study Of The Relationship Between Facial Feature And Occlusal Vertical Dimension

Objectives:As is known to us, disease such as edentulous, dentiton defect and severe worn dentition will not only lead to loss of occlusal relationship, but also disturb the equilibrium relation between occlusion, temporomandibular joint and muscle,then give rise to several complication. As a result, occlusal reconstruction should be devoted to this kind of patient, among which establishment of occlusal vertical dimension(OVD) is of key importance. This study would like to explore the novel method to obtain the OVD by combination of lateral radiographs and digital photo. We also try to find out the relationship between OVD and facial feature by measurement of the length and angle of facial hard and soft tissue landmarks.Method:The study sample consisted of100participants, who were patients in Zhejiang University School of Medicine Affiliated Stomatological Hospital. Criteria for case selection include:1) older than50;2)have own of stable occlusal relation;3)their dental arch of maxillary bone and mandible bone are basically harmonious;4)Cross bite and TMJ disease should not be found. We will overlap the lateral radiographs and digital photo by photoshop, then use ratiomethod to measure the length and angle of facial hard and soft tissue landmarks. All of the data was analysed by SPSS18.0. Pearson correlation analysis will be taken to the data, and the data in each group was compared by Kruskal-Wallis H test. Result:The mean value of OVD is62.83±6.11mm, which is related to age, but has no relationship with gender. After the correlation test, we found that OVD has correlations with has correlations with several facial feature, among which he ight of upper lip (HUL)、middle1/3height of the face、distance between su pramental and nasion(NB)、distance between supramental and orbital(OB)、distanc e between supramental and subspinale (AB)、distance between nasion of soft tiss ure and menton of soft tissure (NS-Mess)、distance between nasion of soft tiss ure and pogonion of soft tissure (NS-POS) have strong correlations with OVD se parately. What is more,OVD has great relativity with SNA、SNB、Facial Angl e、Angle of Convexity、Mandibular Plane Angle and Y axis. Regression equation is obtained with the regression analysis of relevant data, the most significant o nes are as follow:OVD=1.234*HUL+34.691(R=0.686,F=87.033);OVD=0.794*Mi ddle1/3height of the Face+49.094(R=0.728,F=110.371);OVD=0.289*NS-POS+29.024(R=0.546,F=11.074);OVD=0.267*NS-Mess+28.727(R=0.588,F=8.502);OVD=0.455*NB+16.624(R=0.575,F=17.877);OVD=0.672*OB+14.626(R=0.621,F=20.006); OVD=0.605*AB+38.667(R=0.493,F=15.684)Conclusion:Overlapping lateral radiographs and digital photos, as a new and unique method to obtain the OVD in clinical,has their own strengths. With this method, we found relationship, even linear relation between OVD and several facial feature.