Disorder of Harmonious Masticatory Muscle Activities and an Uneasiness Sense of Occlusal Contacts

Abstract

The magnitude of masticatory muscle activites and its harmonious activities were examined in two patients who visited here having a trouble in their everyday life because of an uneasiness sense of occlusal contacts after receiving the orthodontic treatments for the adult's patient. Nevertheless the satisfactory forms of occlusion had been obtained orthodontically in both cases, the two patients claimed the sense of uneasiness strongly. Therefore, the mental cause as a factor was guessed. As the results of examination; in one case, the muscle activities of posterior and anterior temporal muscle and masseter muscle of one-side were higly unstable at the rest position, and showed remarkably unbalanced magnitude of muscle activities in one side at the time of chewing and mastication. In the another case, the tranquilizer was being taken, the almost same magnitude of muscle activities on the working side and balancing side at the time of mastication were observed. In both cases, the harmonious activities of masticatory muscles were ruined, despite of getting well-balanced form of occlusion by orthodontic treatment. The author has already found that the patient who has malocclusion discloses a harmonious pattem of muscle activities peculiar to the type of malocclusion. Therefore, it was imagined that a habitual harmonious pattern of masticatory muscle activities before application of orthodontic treatment was retained in the adult patients of these two clinical cases. This harmonious pattern could not accommodate to the occlusal contacts obtained from the orthodontic treatment, thus, adding to the mental factor, it was guessed that a heigh sense of uneasiness of occlusal contacts was caused.