Age-related and sexual features of the mobility of the temporomandibular joints

Introduction. Pathology of the temporomandibular joints (TMJ) is widespread even among young people, and the frequency of its occurrence increases with the age of patients. In this case, there is violated one of the main characteristics of the joints — mobility, which is measured by the mouth opening width (MOW). There is not enough information in the literature on the age and sex characteristics of the TMJ mobility in individuals without pathology of this joint.The aim of the study is to research the mobility of the TMJ in different age groups in men and women without pathology of this joint.Materials and methods. There were examined 714 patients who applied for dental care, aged 20 to 79 years (504 women and 210 men), without pathology of the TMJ. The range of motion in the TMJ was measured using a caliper with thin lips during the opening of the mouth in a neutral head position. The subjects were divided into age groups: 20–29, 30–39, 40–49, 50–59, 60–69 and 70–79 years old.Results. It was found that the most common MOW value was 4,9 cm (range from 4,5 to 5,2 cm). A distribution of relative frequencies corresponding to the normal Gaussian distribution was observed for this indicator. The mobility of the TMJ changed little with age. Analysis of the distribution of temporomandibular joint mobility by age groups of patients with a step of 10 years showed the similarity of the average MOW values in all groups of subjects, except for the group of 20–29 years. Their average values (4,75 cm) were lower than those of the other groups (4,9 cm, p<0,05). It was found that men have a higher mobility of the TMJ compared to women in all age groups (on average by 0,28 cm, p<0,05).Conclusion. Mouth opening widths of 4,6 to 5,2 cm (average 4,9 cm) can be considered as normal. TMJ mobility is not related to age. Consequently, a decrease in the mobility of the TMJ in persons of older age groups cannot be considered as normal age-related changes. TMJ mobility depends on sex. Men have higher TMJ mobility than women in all age groups. Thus, the TMJ differ from other joints not only in their complexity (two joints always work together), but also in age and sex patterns of mobility.