• Physical Therapy Korea
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• v.15 no.4
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• pp.43-49
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• 2008

The objective of this study was to compare the differences on the activity and power of the wrist flexors and extensors in subjects before the use of a wrist extension splint, after nighttime wearing of the splint, and after daytime wearing of the splint. Ten healthy male and ten healthy female students (mean: $22.4{\pm}1.2$ years old) volunteered to wear custom-made wrist splints either during the night or during the day, The hand force of the wrist flexor and extensor, and grip force were measured by PowerTrack II and Dynatron, respectively. At the same time, the activities of the wrist flexor and extensor were recorded by' surface electromyography. The maximal hand force and motor unit recruitment of the flexor carpi ulnatis (FCU) increased significantly (p<.05) when tile subjects wore the wrist splints during the daytime, but the maximal hand power of the FCU decreased with nighttime use of the splints. The maximal hand power and motor unit recruitment of the extensor carpi radialis (ECR) and the ECR/FCU ratio decreased both during nighttime and daytime use. The decrement of the ECR/FCU ratio was significant (p<.05). Wearing a wrist extension splint during nighttime led to the maintenance of a lengthened position of the wrist flexor, resulting in the wrist flexor becoming weak. Wearing a wrist extension splint during the day induced the wrist flexors to be greater. In healthy people, the imbalance between the wrist flexors and extensors may be caused by the use of a wrist extension splint. This study indicates that therapists have to consider whether a splint will be effective, as well as the wearing time, when prescribing splints to people with problems of the musculoskeletal system.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.231-244
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• 2001

This study was conducted to observe the effect on appendage muscle strength according to increase in occlusal vertical dimension. For this study, ten males with a mean age of 21 were selected. The subjects had a complete or almost complete set of natural teeth and reported no subjected symptoms of pain or dysfunction in the masticatory system. The tested occlusal splints were made at the position of increased occlusal vertical dimension of 2mm, 3.5mm, and 5mm from the ICP. Before and after wearing occlusal splints, the appendage muscle strength were tested by CybexII Dynamometer in each subject. The results were as follows : 1. When occlusal vertical dimension was increased, most of mean muscular strength values were increased except for those of supination and pronation of forearm at the position of 5mm increased occlusal vertical dimension. 2. The statistical analyses demonstrated that the increased occlusal vertical dimension position to be significantly stronger than intercuspal position for the muscle strength of the flexion and extension of hip, supination of forearm, external and internal rotation of knee, dorsiflexion and plantarflexion of ankle (p<0.05). 3. At the position of 3.5mm increased vertical dimension displayed the highest mean muscluar strength value than other positions. 4. Statistically demonstrated values, except for supination of forearm, internal rotation of shoulder, were related to lower appendage. Therefore splint was more effective on lower appendage than upper appendage to make muscle strength increased. 5. The mean increased rate of muscular strength tested on knee(57%), ankle(42%), and wrist(20%) were higher than hip(31%), elbow(14%), and shoulder(17%).

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.3
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• pp.169-183
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• 2003

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.