Accurate Evaluation of Balancing-side Contacts in Relation to Internal Derangements of the Temporomandibular Joint : Possible Roles of Balancing-side Protection

Balancing-side contacts were precisely evaluated in relation to internal derangements of the temporomandibular joint. Balancing-side contacts were classified into the three following groups: 1) Severe balancing-side interference, 2) balancing-side interference and 3) balancing-side protective contacts. Balancing-side protective contacts were defined as balancing-side occlusal contacts on lower first and/or second molar in lateral excursive movements, which are observed only when clenching forces are exerted. The prevalence of the balancing-side protection was revealed to be highly correlated with that of internal derangements of temporomandibular joint. These results strongly suggest that balancing-side protection might play an important role as a regulating mechanism in the etiology of internal derangements of temporomandibular joint