The distribution of occlusal contacts in the intercuspal position and temporomandibular disorder

The aim of this study was to describe the distribution of occlusal contacts in subjects with signs or symptoms of temporomandibular disorder (TMD), and to assess whether any difference exists with healthy subjects. Twenty-five university dental students with complete natural dentition who exhibited TMD (13 females and 12 males, age from 19 to 30 years) and 25 age- and sex-matched controls entered the study. Occlusal contacts were evaluated in the intercuspal position and wax registrations were made in all subjects. Occlusal contacts were classified according to location and intensity. No differences were found between TMD and control groups for the overall number and distribution of contacts or for any side and intensity of contact. An intra-subject analysis showed that TMD subjects had significantly greater bilateral asymmetry in the number of contacts than controls. Median absolute difference of the number of contacts on right and left sides was 3 (95% CI, 2-4) in TMD subjects and 2 (95% CI, 1-2) in controls. In TMD subjects with mono-lateral TMD there was a significant concordance (88.9%) between the side of disorder and the side of higher number of contacts. These findings, while confirming that a significant relationship exists between distribution of occlusal contacts and TMD, further suggest that in young adults it may be primarily expressed by asymmetries in occlusal contact patterns. Existence and aetiology of any association of TMD with occlusal contacts should be further investigated.