• Journal of Oral Medicine and Pain
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• v.14 no.1
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• pp.35-42
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• 1989

악구강계의 질환을 진단하고 치료후의 예후를 판정하기 위하여 maximal clenching시에 측정된 tooth contacts의 수와 분포가 이용되어 왔다. 그러나 maximal clenching시 반복된 tooth contacts의 측정은 저작근 피로등 문제점을 가지고 있다. 본연구는 건강한 성인 15명을 대상으로 maximal clenching 및 habitual clenching시 T-Scan system을 이용하여 치아접촉 수와 접촉시간을 측정, 비교 검토하여 habitual clenching을 이용한 방법이 Tooth contacts의 연구에 이용될 수 있는지를 확인 하는데 목적이 있으며, 연구결과는 다음과 같다. 1. Habitual clenching시 upright, semisupine position에서의 전측두근의 근활성은 maximal clenching시의 64.5%, 61.9% 및 73.3%로 나타났다. 2. Maximal clenching시 치아접촉 수와 접촉시간은 16.82개 및 0.429초로 나타났으며 habitual clenching시에는 11.65개 및 0.177초로 나타났다. 3. 치아접촉수와 접촉시간은 체위에 따라 크게 변화되지 않았다. 4. 치아접촉수와 접촉시간의 측정시에 habitual clenching을 이용하는 방법이 maximal clenching을 이용하는 방법보다 재현성이 더 높은 것으로 나타났다. 5. Tooth contacts의 연구시 habitual clenching을 기준으로 사용할 수 있다.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2476-2479
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• 1998

The masticatory muscle relaxation appliance is developed to improve the malhabit of tooth clenching of the wearer. The repeated clenching of the tooth causes excessive attrition of tooth set. The intraoral appliance measures the tooth clenching pressure data and transmits the data to masticatory muscle relaxation appliance. The appliance compares the pressure data with the reference value and generates the warning signal. The relaxation appliance also stores the clenching pressure data for clenching habit analysis. The appliance is designed with a microprocessor, real time clock, nonvolatile read write memory and dual serial communication ports.

• Journal of Oral Medicine and Pain
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• v.16 no.1
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• pp.25-32
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• 1991

The author studied the changes of electromyographic activities of the masseter and anterior temporal muscles during maximal clenching before and after stabilization splint wearing. It also studied the changes of the symmetry of the muscle activity during maximal clenching. For this study, 15-healthy-female-students were selected. The obtained results were as follows : The EMG activities of right and left anterior temporal muscles and right masseter muscle during maximal clenching immediately after wearing of the stabilization splint were not changed compared with before wearing of the stabilization splint. The EMG activities of right and left masseter and anterior temporal muscles during maximal clenching were significantly increased after 1 week and 4 week-use of the stabilization splint(p<0.01). The asymmetric indices of the EMG activities of right and left masseter and anterior temporal muscles during maximal clenching immediately after wearing of the stabilization splint were not changed compared with before wearing of the stabilization splint. The asymmetric indices of the EMG activities of right and left anterior temporal muscles during maximal clenching were significantly decreased after 1 week and 4 week use of the stabilization splint(p<0.01). and that of masseter muscles showed a decreased tendency but there were no significant differences(p>0.05).

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.327-339
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• 1997

This study aimed at evaluating tile relationship between pressure pain threshold(PPT) and electromyographic(EMG) activity in 30 healthy volunteers and 30 patients with temporomandibular disorders. PPTs were determined with electric pressure algometry over masseter, temporalis anterior, sternocleidomastoid, and trapezius muscle during resting and clenching. To obtain more reliable result, two examiners measured PPTs two times on each muscles, randomly. Resting and clenching EMG activity and tenderness of all muscles were measured to evaluate the relationship with PPTs. The collected data were processed by SAS/STAT program. The obtained results were as follows : 1. Pressure pain thresholds in tendered muscles were lower than those in non-tendered muscles. This tendency was more prominant in masticatory muscles than in cervical muscles and in clenching than in resting. 2. There ware a tendency of higher PPTs in unaffected side than in affected side, but there were no significant difference statistically. 3. There wert no difference of PPTs between in preferred side and in ipsilateral side, significantly. 4. There was a significantly positive correlation between resting and clenching PPTs, but there were no correlation between PPTs and EMG activities. 5. Comparison of EMG activity between in higher group and in lower group by resting PPTs didn't show any significant difference. But resting EMG activity in the higher group of clenching PPTs were lower, on the contrary, clenching activity were higher than those in lower groups of clenching PPTs. From this results, the author concluded that the clenching PPTs was more important than resting PPTs in diagnosis of muscle dysfunction. And the author recommanded that all of three following test were performed for the proper diagnosis and treatment of orofacial Pain : muscle tenderness, EMG activity, and PPT.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.1
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• pp.71-92
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• 1999

This study is to analyze the stress and displacement on the jaws during the bilateral and unilateral clenching task on three dimensional finite element model of the dentated skull. For this study, the computed tomography(G.E.8800 Quick, USA) was used to scan the total length of human skull in the frontal plane at 1.9mm intervals. The CAD data were extracted from the tomograms through digitizer(Summa Sketch III, USA) and then reconstructed by means of the spline method in the CAD program. In this project, a commercial software I-DEAS(Master Series ver-sion 3.0, SDRC Inc, USA) was used for three-dimensional stress analysis on the finite element model. which consists of articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. The results are as follows. ; 1. During the bilateral clenching, each major muscle forces caused high stresses on various areas of skull: masseter muscle on articular disc and teeth ; temporal muscle on mandible and periodontal ligament ; medial pterygoid muscle on the temporomandibular joint. During the unilateral clenching, masseter muscle induced the maximum stress ; medial pterygoid muscle the minimum stress. 2. During the bilateral clenching, higher compressive stresses on articular disc were generated by the masseter muscle and higher deformation occurred on the most front outer sites. And during the unilateral clenching, temporal muscle and medial pterygoid muscle exerted their forces to twist temporomandibular joint area of the balancing side and induced a higher compressive stresses on the front outer sites of articular disc. 3. During the bilateral clenching, the masseter muscle bended the mandible outwardly, and then caused tensile stresses on the lingual surface of mandibular symphysis. And the medial pterygoid muscle caused tensile stresses on the labial surface of mandibular symphysis. 4. When each muscles were simultaneously applied on jaws, a high stress and displacement took place on mandible rather than on the maxilla. Also, a high stress and displacement took place during the unilateral clenching rather than during the bilateral clenching.

• Journal of Oral Medicine and Pain
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• v.20 no.1
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• pp.159-169
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• 1995

The purpose of this study was investigating the effects of pivot splint on width of the temporomandibular joint space in order to get the basic data for clinical applications. Pivot splint could be used for treating the patients with temporomandibular disorders, especially for chronic closed lock which would not be reduced by joint manipulation or with other methods. So it is necessary to have a lot of underlying data for using pivot splint, but there is few available reports related to mechanical principle or clinical results of the splint. Healthy twenty dental students wee collected for this study and pivot splint with 2.5mm high right-side pivot was used. Next, transcanial projection was taken and width of joint space at there mandibular positions were measured : habitual occlusion position, clenching position with splint, and clenching position with splint and mandibular force. The data were processed with SAS statistical program. The obtained results were as follows : 1. Ipsilateral posterior joint space width was increased on clenching the pivot splint, but joint space widths of contralateral side were not significantly changed. 2. Superior and posterior joint space width were increased on clenching the pivot splint with mandibualr force on both ipsilateral and contralateral side. 3. Ipsilateral joint space widths were not significantly changed from habitual occlusion position to clenching the pivot splint with active mandibular force, but in case of with passive mandibular force, posterior joint space width was significantly increased. 4. Correlationships between mandibular positions were more significant at anterior joint space than at superior or posterior joint space. But the correlation between clenching and clenching with mandibular force was significant at all the three joint space.

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.45-53
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• 1991

저자는 두개하악 장애로 교합상치료를 받고있는 42명의 환자를 대상으로 치료전, 치료후 1개월, 3개월, 6개월째에 주관적 평가, 임상적 검사, 근전도 검사, 컴퓨터 교합 분석을 시행하여 다음과 같은 결론을 얻었다. 1. 주관적 평가인 visual analogue scale과 Helkimo's anamnestic dysfunction index는 유의하게 감소하였다. 임상적 검사시 MM(mandibular movement), TM(TMJ capsule palpation), EM(extraoral muscle palpation), Di(Helkimo's clinical dysfuction index)는 유의하게 감소하였고 무통성 개구량은 유의하게 감소하였다. 2. 42명의 환자중 10명에서 교합변화가 관찰되었으며, 5명에서 치주질환, 2명에서 치아 과민감, 1명에서 구토경향이 관찰되었다. 3. 치주칠환을 보이는 10명의 환자중 3명은 교합상치료 이전부터 치주질환에 이환된 상태였으며 3명에서는 교합변화가 함께 관찰되었다. 4. 교합변화를 보인 10명의 환자중 교합상의 장착시간을 줄였을 때, 3명이 원래의 교합상태로 회복되었고 4명은 부분적으로 회복되었으며 3명에서는 변화를 관찰할 수 없었다. 5. 악관절 내장 제 5기 환자에서 교합변화가 더 빈번히 나타났으며 통계적으로 유의한 차이를 보였다. 6. Habitual clenching 시와 Maximal clenching 시 사이의 치아접촉점 수, maximal clenching 시의 치아 접촉점의 수와 접촉 치아수 사이에 매우 유의한 상관관계를 보였고, habitual clenching 시의 치아접촉점의 수와 접촉 치아수, Habitual clenching 시와 maximal clenching시 사이의 치아 접촉시간에서도 유의한 상관관계를 보였다.

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.105-115
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• 1991

The purpose of the study was to evaluate the occlusal stability at the moment of dynamic occlusal tooth contact and to investigate the correlation between the occlusal stability and the masticatory muscle activities. It also evaluated the effect of short-term use of occlusal splints on the occlusal stability and the masticatory muscle activities in patients with temporomandibular disorders during maximum voluntary clenching by synchondronized with temporomandibular disorders during maximum voluntary clenching by synchronized use of the T-Scan system(Tekscan, Inc, USA) and K6-Diagnostic system(Myo-tronics Research, Inc, USA) The author measured its distance from retruded contact position(RCP) to intercuspal position(IP), average of contact intervals(ACI), total left-right statistics(TLR), average muscle activities of masseter and anterior temporal muscles during maximum voluntary clenching in 20 patients with temporomandibular disorders and 22 dental students as a control group. The data were compared between two groups and investigated for any correlations between the parameters. The results were as follows : 1. Both of the mean average of contact intervals and the mean absolute value of total left-right statistics during maximum voluntary clenching were increased in the patient group when compared with the control group. 2. Muscular disharmony of anterior temporal muscles of patient group is significantly greater than that of control group. However, muscular disharmony of masseter muscles of patient group is not significantly greater than that of control group. 3. There were significant correlations between muscular disharmony of anterior temporal muscles and average of contact intervals as well as total left-right statistics, and also between muscular disharmony of masseter muscles and total left-right statistics. 4. There were not any significant correlations between distance from RCP to IP and any other parameters. 5. There were a significant decrease in total left-right statistics and muscular disharmony of anterior temporal muscles during maximum voluntary clenching after a 1week use of occlusal splint in the patient group.

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.27-35
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• 1991

In order to evaluate muscular activity patterns of masticatory muscles and asymmetry patterns of muscular activity according to the levels of occlusal force, twenty-one individuals of age ranged from 23 to 27 years were examined. They were selected according to the following criteria : 1) no symptoms of temporomandibular disorder, 2) complete dentition except third molars, 3) normal or Angle's class I molar relationship and 4) no experience of dental treatment. The electromyographic amplitudes was measured for evaluation of muscular activity and asymmetric patterns of masseter and anterior temporal muscle during unilateral clenching at the levels of 10%, 20%, 40% and 50% of the maximum occlusal force by use of electromyogram and bite force meter. The obtained results were as follows : 1. The muscle activity indices of masticatory muscles of clenching side at the clenching levels of 10%, 20% and 30% of the maximum occlusal force were -19.12, -9.87, -0.49%, so that activity of anterior temporal muscle was dominant than that of masseter muscle. At the levels of 40%, 50% of the maximum occlusal force, muscle activity indices were 4.68%, 6.70%, so that activity of masseter was dominant at all level and as the levels of occlusal force was increased, muscular activity index was tend to decrease. 2. In masseter, asymmetry indices of muscular activity at the levels of 10%, 20% of maximum occlusal force were -10.34 and -1.24%, so that muscular activity of non-clenching side were dominant and at the levels of 30%, 40% and 50% each of maximum occlusal force, muscular activity was dominant on clenching side as 4.68, 7.18 and 10.9%. In anterior temporal muscle, asymmetry indices were 33.38%, 25.46, 2095, 10.23 and 15.45% at the levels of 10%, 20%, 30%, 40% and 50% each of maximum occlusal force, so that activity of clenching 15.45% at the levels of 10%, 20%, 30%, 40% and 50% each of maximum occlusal force, so that activity of clenching side was dominant than that of non-clenching side at all levels, but as the levels of occlusal force was increased, asymmetry indices of muscular activity was tend to decrease. 3. Between both sides, average electromyographic amplitudes of masseter and anterior temporal muscle were correlated, so that as the levels of occlusal force was increased, average electromyographic amplitudes of both side in same muscle were increased proportionally. But asymmetry indices between muscular activities of masseter and anterior temporal muscle were not correlated.

• Journal of Oral Medicine and Pain
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• v.13 no.1
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• pp.85-93
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• 1988

The author studied maximum clenching EMG activities of temporalis anterior and masseter muscle during canine guidance and centric occlusion. It was performed before and after anesthesia of maxillary and mandibular canines. The 22 normal subjects (15 males and 7 females) who had healthy maxillary and mandibular canines were selected. Their occlusal contact scheme was canine guidance during movement and they did not have temporomandibular disorder. The results were as follows : 1. The maximum clenching EMG activities of temporalis anterior and masseter muscle during guidance were less than those during centric occlusion. 2. After left maxillary and mandibular canines were anesthetized with 2% lidocanine with 1:100,000 epinephrine, the maximum clenching EMG acivities of temporalis anterior and masseter muscle during left canine guidance were greater than those before anesthesia of left maxillary and mandibular canines(p<0.01) 3. The maximum clenching EMG activities of temporalis anterior and masseter muscle during right guidance were not significantly different between before and after anesthesia of left maxillary and mandibular canines(p>0.05).