Oral habits and their association with signs and symptoms of temporomandibular disorders in adolescent girls.

A group of 248 randomly selected high school girls, aged 15-16 years, completed a questionnaire and were examined clinically with regard to various oral habits and signs and symptoms of temporomandibular disorders (TMD). Common habits reported in the literature, such as gum chewing, nail biting, biting foreign objects, clenching and bruxism, eating seeds and crushing ice, as well as two less reported habits, 'jaw play' and continuous arm leaning, were evaluated. The most outstanding finding was the high prevalence and intensity of gum chewing among our study group: 92% of the girls chewed daily and 48% chewed gum for more than 3 h a day (intensive gum chewing). Statistically significant associations were found between intensive gum chewing and muscle sensitivity (P<0.001) and joint noises (P<0. 05), and between crushing ice and muscle sensitivity to palpation (P<0.005). A positive association was found between 'jaw play' and joint disturbances: reported joint noises (P<0.01), catching of the joint (P<0.01) and joint tension (P<0.001). A positive association was also found between arm leaning and reported joint noises (P<0. 05), catching (P<0.05), and joint tension (P<0.005). There was no association between the presence of bruxism and muscle sensitivity to palpation or joint disturbances. The potential harmful effects of intensive gum chewing, 'jaw play', continuous arm leaning and ice crushing are presented in this study. In light of these findings, the professional community should address these habits with proper data gathering, examination and consultation.