Statement of Problem: In recent years, the prevalence of temporomandibular disorders among children and adolescents has increased, however, no study on the correlation between occlusal relations and temporomandibular disorders, in Mashhad adolescents, has been conducted yet.

Purpose: The aim of this study was to survey the relationship between occlusal indices and temporomandibular disorders (TMD) among Mashhad adolescents, with the age range of 11-14 years old.

Methods and Material: In this descriptive cross-sectional study, 1066 students (533 males and 533 females), age ranging from 11-14 years old (12.620.96 years), from seven Mashhad educational regions, were selected. Temporomandibular joints were thoroughly examined for all subjects. All occlusal indices including dentition system, angles classification, types of malooclusion such as cross-bite, deep-bite as well as types of lateral occlusion, premature contacts in lateral and protrusive movements were investigated. Data were analyzed statistically using, Chi-Square and logestic regression tests.

Results: The prevalence of TMD was 23.5%. There was no significant relation between TMD and type of dentition, angles classification and type of occlusion in lateral movements, however, statistically significant relation was found between TMD and deep over bite (P<0.05). Premature contacts in lateral movements at balancing side were proved to be significant etiologic factors of TMD (P=0.003).

Conclusion: In the present study, premature contacts at balancing side and secondary deepbite malocclusion were considered to be the most important etiologic factors of TMD.