Abstract
According to our recent investigation that the increase in the occlusal vertical dimension made the appendage muscle strength got higher, the occlusal appliances were made by increasing the occlusal vertical dimension "from the centric relation" position of the mandible. In this experiment, the authors tried to study the change in the appendage muscle strength due to increase in occlusal vertical dimension from intercuspal position(ICP) of mandible with the same subjects and manner as the former experiment. For this study, ten male athletes in a mean age of 23 year who were joined the former study were selected. All the subjects had a complete or almost complete set of natural teeth and reported no subjective symptoms of temporomandibular disorders. Upper and lower casts were mounted on the semi-adjustable articulator at the intercuspal position and a point was marked on the attached gingival area between the right canine and the right 1st. premolar in each upper and lower cast. From the points, the occlusal vertical dimension was increased by 2mm, 3.5mm and 5mm, and then each 10 maxillary type occlusal splint at each 3-increased position were fabricated with heat curing clear acrylic resin. Including the intercuspal position, the 3 kinds of occlusal splints were placed on the subjects individually, and then isokinetic muscle strength on 7 parts of the human appendage which are shoulder, knee, ankle, wrist, forearm, elbow and hip was measured with the CYBEX 6000 SYSTEM (Lumex, NewYork, USA). The results were as follows: The highest mean value in muscular strength was shown at the position of 2mm-increased vertical dimension. The muscle strength during internal/external rotation of shoulder and knee, plantarflexion of ankle, flexion of elbow, and flexion and extension of hip at the increased occlusal vertical dimension position were significantly higher than them at the intercuspal position (p<0.05). Only in view of the increase in the appendage muscle strength, regardless of the way of making the occlusal splints by elevating the occlusal vertical dimension from the centric relation position or intercuspal position, the occlusal splints had an effect on the increase of isokinetic muscle strength at the occlusal vertical dimension which increased within the proper range on the habitual arc of closure.
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