Association between loss of occlusal support and symptoms of functional disturbances of the masticatory system

The purpose of this study was to evaluate the association of loss of occlusal support with symptoms of functional disturbances of the masticatory system, in particular with the ones related to the temporomandibular dysfunction. A total of 483 adult subjects randomly selected from the population living in the municipality of Segrate, northern Italy, were studied. Subjects were interviewed by questionnaire about oral conditions and occurrence of symptoms of disturbances of the masticatory system. Also, denture was examined by dentists during the interview. Loss of occlusal support was observed in 60.2% of the subjects, symptoms of functional disturbances in 68.7% and temporomandibular dysfunction in 55.1%. At univariate analysis loss of occlusal support was mainly associated with a feeling of stiffness or fatigue of the jaws (P < 0.001), difficulty in closing the mouth (P < 0.005) and difficulty on mastication (P < 0.0001). Association with temporomandibular dysfunction as a whole was significant also (P < 0.001). Multiple age- and sex-adjusted logistic analysis disclosed a significant strong impact of loss of occlusal support on difficulty with mastication (odds ratio = 7.0, P < 0.0001). At that analysis, no significant relationship resulted with symptoms of temporomandibular dysfunction. These findings confirm that presence of an adequate occlusal support is a relevant factor in maintaining an efficient chewing, and also suggest that it may play any indirect role in preventing occurrence of symptoms of temporomandibular dysfunction.