Objectives. It is generally accepted that the aetiology of craniomandibular dysfunction (CMD) is multifactorial. Different types of malocclusion, oral parafunctions especially bruxism, trauma of the mandible or temporomandibular joint (TMJ) and emotional stress are known aetiologic factors. Research has been conducted into the relationship between each of these aetiologic factors and the signs and symptoms of CMD. However, such an approach does not control for the simultaneous effect of other factors responsible for the development of the dysfunction. The purpose of this study was to investigate the effect of each aetiologic factor on the signs and symptoms of CMD in children, controlling for the effect of all other known factors by means of a multifactorial analysis. Methods. A sample of 314 children, aged 6-8 years, was examined clinically for signs of CMD and morphologic and functional malocclusion. Symptoms of CMD and oral parafunctions were recorded by the same investigator in an interview. Emotional stress was measured through urinary catecholamines including epinephrine, norepinephrine and dopamine, detected in a 24-h urine sample, using high performance liquid chromatography. A questionnaire was distributed to the parents to collect information regarding socioeconomic factors and the history of dentofacial injuries. A logistic multiple regression was carried out to estimate the partial effect of each aetiologic factor. A 95% probability level was used. Results. Posterior crossbite with lateral shift significantly affected the probability of child developing deviation of the mandible on opening. Similarly, posterior crossbite and epinephrine had a significant impact on TMJ tenderness, overjet had an effect on clicking, clenching and biting of objects had an effect on muscle tenderness, and lip/cheek biting influenced dysfunctional opening. Of the symptoms reported, pain on wide opening was affected significantly by lip/cheek biting. Conclusion. On the basis of these results, it can be suggested that parafunctional and some structural and psychological factors may increase the probability of the child developing the signs and symptoms of CMD
