Investigation of the relationship between oral parafunctions and temporomandibular joint dysfunction in Turkish children with mixed and permanent dentition.

The purpose of this study was to investigate the relationship between temporomandibular joint (TMJ) dysfunction, bruxism and oral parafunctions in the permanent and mixed dentition of Turkish children. Examinations were performed on 59 children (26 girls and 33 boys) without TMJ dysfunction and 123 children (54 boys and 69 girls) with TMJ dysfunction in the mixed dentition. In the permanent dentition 89 children without TMJ dysfunction (45 girls and 44 boys) and 123 children with TMJ dysfunction (69 girls and 54 boys) were inducted into this study. The children with oral parafunctions (bruxism, nail biting and thumb/finger sucking) were determined through questionnaires. The Z-test was used for the analyses of the correlation between variables and differences between the groups. Generally a significant correlation was found between finger/thumb sucking and nail biting and TMJ dysfunction in the mixed dentition and bruxism was observed significantly to be associated with TMJ dysfunction in the permanent dentition (P < 0.05). The evaluation of the results showed that in the mixed dentition groups nail biting was significantly higher in the girls with TMJ dysfunction and finger or thumb sucking was significantly higher in the boys with TMJ dysfunction compared with those without TMJ dysfunction (P < 0.01). In the permanent dentition; bruxism and thumb/finger sucking were significantly higher in girls with TMJ dysfunction higher than those without TMJ dysfunction (P < 0.05). However, thumb/finger sucking was significantly higher in boys without TMJ dysfunction than with TMJ dysfunction (P < 0.05). The results of this study showed that the association of parafunctions and TMJ dysfunction is present in the mixed (thumb/finger sucking and nail biting) and the permanent dentitions (bruxism).