The aim of this study was to explore the association between signs and symptoms of temporomandibular disorders (TMD) and orthodontic treatment need in orthodontically untreated children and adolescents. One thousand five hundred and ninety-seven subjects aged 11-19 years, without previous orthodontic history, from sixteen randomly selected public schools in Zagreb, Croatia, were examined. Malocclusion characteristics were assessed by using the criteria proposed by Bjork et al., the Dental

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... tic Index, and the Aesthetic Component of Index of Orthodontic Treatment Need. Data on TMD signs/symptoms and parafunctional behaviour were obtained by means of questionnaire and clinical examination, respectively. Multiple logistic regression models were used for analysis. Twenty-two percent of children and young adolescents had one or more signs of TMD, ranging from 17% in age of 11 years up to 24% in age of 19. There was poor correlation between presence of TMD and orthodontic treatment need. Multiple logistic regression models showed that Class III, crowding and spacing were related to mandibular deflection on opening. Ectopic eruption was related to TMJ clicking, and severely tipped teeth with reduced mouth opening. Headaches presented a positive relationship with reverse overjet and severe rotations, and tooth wear with crowding, spacing and lateral openbite. Age, female gender and parafunctional habits were related to several TMD signs. Although logistic regression models were statistically significant (p < 0.05) malocclusions, parafunctional behaviours, age and gender accounted for less than 20% of the variability in TMD signs/symptoms. TMD signs and symptoms seemed to be poorly related to malocclusions or treatment needs.