To Study The Relation Between The Depth Of The Curve Of Spee And Tempommandibular Disorders Of College Students

Objective:By measuring the depth of curve of Spee of a large number of college students and correlating the results of statistical analysis to explore the relation between Temporomandibular joint disorders (TMD) and the curve of Spee, so as to provide a theoretical basis for the role of the depth of curve of Spee in the development of Temporomandibular joint disorders.Materials and Methods:Selecte 192 undergraduate students of Shandong University School randomly (83 males and 109 femalesaged 19-24 years old, average age 22.3), and divide them into two groups according to the diagnostic criterias of temporomandibular joint disorders. And calculate the CMI of TMD group. After the preparation of the plaster models and standardization shoot pictures, import AUTOCAD2014 for analysis. Measure the depth of bilateral Spee curve and calculate the mean, then analyze the measurement results by SPSS 17.0.Results:(1) Relation between the incidence of TMD and the depth of curve of Spee: According to the mean depth of curve of Spee, devide the 192 samples into groups,0.25mm as the interval, and calculate the incidence of temporomandibular joint disorder of each packet. The incidence of each group was tested by spearman correlation (0.05 confidence level). Incidence of TMD and depth of Spee curve were negatively correlated (r=-0.731) in the range of 0-2mm; incidence of TMD and depth of Spee curve were positively correlated (r= 0.786) in the range of more than 2mm.(2) Relation between the depth difference of the left and the right sides of Spee curve and TMD:Divide 192 samples into two groups nalmely TMD group and control group according to the diagnostic criterias of TMD. The depth of the left and right sides of curve of Spee will be paired samples T-test (confidence level 0.05 level) in each group. The results showed that the depth of two sides Spee curve in TMD group had statistics difference(P= 0.01), while that of the control group had no statistics difference (P= 0.109).(3) Relation between the mean depth of Spee curve and TMD:Divide 192 samples into two groups nalmely TMD group and control group according to the diagnostic criterias of TMD and calculate the mean depth of the curve of Spee, Analyse the datas by independent sample T-test (0.05 confidence level). The result was that the mean depth of TMD group and control group were 2.29±0.92 and 2.05±0.58, t= 1.89, P= 0.062. It prompted that the two groups had no statistics difference in mean depth of Spee curve.(4) Relation between the CMI index and the mean depth of bilateral side Spee curve:Calculate the mean depth of the two sides of Spee curve of 65 TMD samples and divede them into groups 0.25mm as the interval. The samples’ whose mean depth was in the range of 0-2 mm and beyond the range of 2mm corresponding CMI index were tested by pearson detection (0.05 confidence level). The results were that in the range of 0-2mm, n= 39, P= 0.064, r= 0.141, beyond the range of 2mm, n= 26, P= 0.045, r= 0.336. It showed that CMI index had no relevance with the mean depth of the bilateral Spee curve in 0-2mm, while weak relevance was showed when the depth was greater than 2mm.(5) Relation between the CMI index and bilateral Spee curve depth difference: Calculate the depth difference of bilateral Spee curve of 65 TMD samples and test each sample’s corresponding CMI index by pearson detection (Confidence 0.05 level), The test result was that P= 0.037, r= 0.356. It implied the CMI index had weak correlation with the depth difference of bilateral Spee curve.Conclusion:1.For teenagers, the incidence of TMD had relevance with the depth of Spee curve. The incidence was lowest when the depth was nearby 2mm. The depth deviated from 2mm more seriously, and the possibility of occurrence of TMD also increased.2.For TMD patients, the depth of the bilateral Spee curve often had significant difference,while it had no significant difference for the normal. This indicated that for the same individual, with the increase of the depth difference of bilateral curve of Spee, the risk of TMD increased.3.CMI index is a indicator which is used for valuing TMD severity, but for TMD patients, the size of the mean depth of Spee curve and the size of bilateral differences, they two both didn’t show a significant correlation with CMI index. It suggested that for TMD patients, depth difference of Spee curve possibly had no significant impact on severity of TMD symptoms.