2 Objectives: To determine the prevalence of temporomandibular disorder and associated factors in an 3 adolescent sample from Recife, Brazil. Materials and Methods: A cross-sectional study was conducted 4 with 1342 adolescents aged 10-17 years. The Research Diagnostic Criteria for Temporomandibular 5 Disorder (RDC/TMD) was used by calibrated examiners to evaluate the presence and levels of chronic 6 pain. To evaluate the socioeconomic conditions, the Brazilian Economic Classification Criteria (CCEB)7questionnaire was answered by the subjects. Data were analyzed by means of binary logistic regression in 8 SPSS. Results: The results showed that 33.2% of the subjects had TMD irrespective of age (p= 0.137) or 9 economic class (p=0.507). Statistically significant associations were found between TMD and gender (p= 10 0.020), headache/migraine in the past six months (p=0,000) and the presence of chronic pain (p=0,000). In 11 final model, logistic regression showed that chronic pain contributes to the presence of TMD. Conclusions:
12The prevalence of TMD was considered high (33.2%) and adolescents with chronic pain were more likely 13 to have TMD. Clinical Relevance: The data contribute to the understanding of TMD among adolescents 14 and to the development of preventive measures and polices to identify the dysfunction promptly. 15 16 17 19 temporomandibular joint (TMJ), masticatory muscles and associated structures occasionally occur in 20 infants, children and adolescents. Temporomandibular disorder (TMD) is a collective term for a group of 21 musculoskeletal and neuromuscular conditions that include several clinical signs and symptoms, such as 22 pain, headache, TMJ sounds, TMJ locking and ear pain [1], involving the muscles of mastication, the TMJ 23 and associated structures [2]. 24 The prevalence of TMD in adolescents has been reported in recent studies showing a percentage 25 of 9.0% to 48.7%, evaluated by the Research Diagnostic Criteria for Temporomandibular Disorders 3 38 with poorer oral health-related quality of life (OHRQoL). The Brazilian Economic Classification Criteria 39 (CCEB) was developed by the Brazilian Association of Research Companies [23] for population 40classification into groups according to economic class. This classification is based on the possession of 41 goods and not based on family income, scores vary from zero (the poorest) to 46 (the richest).
42The cumulative effect of muscle activities increases the likelihood of presenting painful TMD [24].
43Prolonged masticatory muscle pain is likely to become a chronic condition, and continuous pain may 44 eventually produce chronic centrally mediated myalgia [25]. Through evaluation of adolescents diagnosed 45 with moderate to severe TMD, a higher level of electromyographic activity was found in the masseter and 46 temporal muscles at rest and during chewing [26]. Recent findings have suggested that prepubertal children 47 with high levels of sedentary behavior, low levels of cardiorespiratory fitness and low body fat content may 48 have increa...