RESUMEN
Since different factors are effective in high spreading of TMD this study was conducted to determine the prevalence of TMD and related factors in patients referring to dental school of Azad University of Tehran in 2005. This descriptive-analytical study was conducted on 261 patients reffered to the faculty of Dentistry of Azad University of Tehran in 2005. All samples were evaluated through three frameworks. The data were statistically analysed by chi-square test. The average age of the samples was 34 +/- 12.4. Eighty nine samples were suffering from TMD. The prevalence of TMD was 34/1%. All related factors under the study [age-sex-parafunction habits-trauma-orthodontics-anxiety and depression] showed significant correlation with TMD [P<0.05], while among TMD and occlusion [Angle classification], no significant correlation was observed. The frequency of TMD was almost high. Among All related factors except for the occlusion, there was a significant relationship. Considering the recognized complications of this disease, it is recommended to study the etiology