• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.389-412
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• 1992

Along with form and function relationship of craniofacial growth comes a concern for the masticatory muscles with postnormal occlusion. It is the aim of this study to grope the certain differences upon the electromyographic activities of the masticatory muscles between normal occlusion and class II malocclusion during the varieties of oral functions. 26 persons of normal occlusion whose mean age were 18.9-25.6 years and another 26 persons of class II malocclusion whose mean age were 19.0-28.9 years served for this study. The electromyographic recordings processed by $Medelec^{\circledR}$ MS 25 EMG apparatus were taken from the anterior and posterior temporal, and anterior and posterior masseter muscles of both sides, and suprahyoid muscles as well. Analyses of the data toward such specific activities as mandibular rest, maximal biting, chewing gums and swallowing peanuts turned out the following summary and conclusions. 1. The maximal mean amplitude of the posterior temporalis showed significant augmentation in class II malocclusion, however the anterior temporalis, posterior masseter, and suprahyoid muscles manifested meaningful diminutions. 2. Stronger posterior temporalis and weaker anterior masseter and suprahyoid muscles were arranged in maximal biting with parameters of maximal mean amplitude. 3. The anterior temporalis of working side expressed smaller maximal mean amplitude in class II malocclusion. Significant swelling in duration were shown at anterior and posterior temporalis of working side, and posterior temporalis of balancing side in class II malocclusion, and marked reduction at anterior masseter of balancing side and posterior masseter of working side as well. The lessened latency were expressed at anterior masseter of working side, and anterior and posterior masseter of balancing side. Class II malocclusion group had significant prolongation of silent period duration. Mean silent period duration of 10.75 msec in normal occlusion and 24.37 msec in class II malocclusion were calculated. 4. Significant augmentations of maximal mean amplitude while swallowing peanuts were yielded at right anterior temporalis and posterior temporalis of both sides, however left anterior masseter and right posterior masseter showed diminution. No significant differences in duration showed at every muscle examined in class II malocclusion group.5. Weaker masseter and stronger temporalis were suggested as characteristics of class II malocclusion.

• Journal of Oral Medicine and Pain
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• v.39 no.2
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• pp.55-62
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• 2014

Purpose: This study aims to evaluate the changes in soft tissue thickness of the masseteric region after injection of botulinum toxin type A (BTX-A). Methods: Twenty-four data acquired from medical records were classified into 4 groups: bruxer group that received masseter muscle injection only (M-B), bruxer group that received both masseter and temporalis muscle injections (MT-B), non-bruxer group that received masseter muscle injection only (M-NB) and non-bruxer group that received both masseter and temporalis muscle injections (MT-NB). Injection dose of BTX-A was 30 units for each masseter muscle and 20 units for each temporalis muscle. We measured the reduced thickness of the masseteric region before and after 12 weeks after injection using cone-beam computed tomography. Results: Among the patients that received both masseter and temporalis muscle injections, bruxer group showed a tendency to have more reduction in masseter muscle thickness than non-bruxer group. The difference in reduced thickness between M-B and MT-B tended to show greater than the difference between M-NB and MT-NB. Conclusions: In case of masseter hypertrothy patients with bruxism there was a tendency to show a difference in reduced thickness of soft tissue between the group that received both masseter and temporalis muscles injection and the group that received masseter muscle injection only hence a thorough inspection before the injection of BTX-A is condisered to be needed.

• 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).

• The Korean Journal of Pain
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• v.30 no.4
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• pp.304-307
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• 2017

A 19-year-old male patient presented with facial hemi-atrophy with unilateral spasms of the masseter and temporalis muscles. Ultrasound therapy and Transcutaneous Electric Nerve Stimulation therapy, known as combination therapy, were given on alternate days for 2 weeks. At the end of 2 weeks of combination therapy the patient reported a drastic reduction in the number of episodes of muscle spasm. The visual analog scale score for tenderness of the masseter and temporalis was also markedly reduced. No one has previously used combination therapy for the treatment of facial hemi-atrophy with hemi-facial spasms. The encouraging results of the combination therapy has prompted us to document this study.

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.37-44
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• 1991

The author has synchronously recorded average electromyographic activities of temporalis anteriors and masseter muscles and the maximum bite force on the mandibular first molar on the prferred chewing side. These activities were recorded in order to study the EMG activity pattern of the working side and the balancing side to maximum bete force and functioning state of muscle in 30 patients with TMD and in 30 healthy subjects as controls. The results were as follows : 1. The maximum bite force on the mandibular first molar on the preferred chewing side was 20.63kg in TMD patients and 53.30kg in the healthy subjects(p<0.01). The maximum bite force in TMD patients was 38.7% of the healthy subjects. 2. The average electromyographic activities of temporalis anterioris and masseter muscles on the working side and the balancing side during maximum bite force were lower in TMD patients than in the healthy subjects(p<0.01). The average electromyographic activities of each muscle in TMD patients were 61.0%-62.8% of the healthy subjects. 3. The proportionalities of average electromyographic activities of temporalis anteriors and masseter muscles on the working side and the balancing side to maximum bite force were greater in TMD patients than in the healthy subjects(p<0.01). 4. Between the working side and the balancing side, the proportionality of average electromyographic activity of temporalis anterior to maximum bite force on the working healthy subjects (p<0.01). The proportionality of average electromyographic activity of working side and the balancing side in both groups (p<0.05).

• Journal of Oral Medicine and Pain
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• v.13 no.1
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• pp.43-52
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• 1988

The author studied masticatory muscle activity and bite force in normal persons without Temporomandibular Disorders(TMD) signs and symptoms, The number of subjects was 15, and the age of them was from 22 to 25 years. Electromyography was used to record the muscle activity in tapping and clenching movement with or without occlusal splint. 3 splints were made from 3 different mandibular position, that if, centric occlusion position, Rocabado's mandibular rest position, Dawson's centric relation position. The thickness of splint was 3.0-3.5㎜ at molar region. The muscle examined were Masseter and Anterior Temporalis attached with surface electrodes and the device used to measure the EMG level was Bioelectric processor Model EM2. After recording the EMG, the author measured the bite force level in clenching movement with bite force meter Model MPM-3000 in the dame position used in the EMG experiment. The obtained results were as follow : 1. With occlusal splints insetion, the amount of decreased muscle activity in Anterior Temporalis was more than those in Masseter. 2. In the three maxillomandibular relationships with occlusal splints, Masseter showed slightly increased level of muscle in centric occlusion but Ant. Temporalis showed decreased level of muscle activity reversely in that position. 3. Muscle activities between Rocabado's rest position and Dawson's centric relation position were generally similar whatever the muscles or the movements the author examined. 4. Bite force in clenching movement increased with splints insertion, especially with the splint registered in centric occlusion position.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.291-296
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• 2021

This study examined the effects of the forward head posture on the maximum mouth opening of the jaw joint and the muscle activity and asymmetry of the temporalis and masseter. The craniovertebral angle was measured in 50 subjects (23.10±2.73 years) who met the selection requirements of the study. The maximum mouth opening, muscle activity, and muscle asymmetry were measured by reducing 0%, 10%, and 20%. As the craniovertebral angle decreased, the maximum mouth opening decreased (p<.001), the muscle activity of the right and left temporalis decreased (p<.001), and the muscle activity of the left temporalis also decreased. (p<.01). The asymmetry rate of the added muscles of the left and right temporalis, left and right temporalis, and masseter increased according to the change in condition (p<.01). The results of this study are expected to help establish a treatment strategy and comprehensive diagnosis for the temporomandibular joint and present a theoretical basis of manual therapy and therapeutic exercises used for the treatment of TMD.

• Journal of Oral Medicine and Pain
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• v.24 no.4
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• pp.421-437
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• 1999

This study was performed to investigate the electromyographic(EMG) activity, firing time and sequence of the mandibular elevator muscle on gum chewing. For this study, 28 patients with temporomandibular disorders(TMD), especially internal derangement of TM joint, and 16 dental students without any signs and symptoms in the masticatory system were selected as the patients group and as the normal group, respectively. The patients group was composed of 14 right and 14 left side affected patients. For recording of EMG activity(${\mu}V$) of the anterior temporalis(TA) and the masseter muscle(MM), and measuring of firing time(millisecond) from the start of mandibular opening movement to the firing of the muscles, BioEMG, BioEGN, and Combo program integrated in the Biopak system(Bioresearch Inc., Milwaukee, USA) were used. Gum chewing stroke was performed in both right and left side for several times, and the first and the second chewing strokes were analysed and compared with regard to EMG activity, firing time, firing sequence, correlation between EMG activity and firing time. The data obtained were analysed by SPSS windows program and the results of this study were as follows : 1. In the patients group, chewing on the affected side showed higher EMG activities in the masseter of the side than those of the contralateral side, but chewing on the unaffected side showed higher EMG activity in the masseter and in the anterior temporalis of the side than those of the contralateral side. 2. There were no difference of firing time between both sides on chewing on the affected side, but firing time in the chewing side were earlier than that of contralateral side on chewing on the unaffected side in patients group. 3. In the normal group, EMG activities in the masseter and in the anterior temporalis in the chewing side were always higher than those of the contralateral side, and there were no difference of firing time between the two sides. 4. In general, firing sequence of four muscles of both sides were ipsilateral TA, ipsilateral MM, contralateral TA, and contralateral MM in earlier order of time in both groups. Correlation coefficients between EMG activity and firing time were negative value, and more significant correlation were appeared in the normal group than in the patients group.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.165-176
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• 1986

The purpose of this study was to investigate electromyographically the relationship between preferred chewing side and side of initial muscle pains. In this study, 20 normal healthy subjects were selected , and each subject chewed randomly chewing gum for 20 minutes to establish preferred chewing side. To induce initial muscle pains, biting force of 10Kg on the gnathodynamometer was maintained by the subjects. And the Bioelectric processor EM2(Myo-Ironies Research, Inc. U.S.A.) with the surface electrodes was used to record the EMG activity during all experimental procedures. The results were as follows; 1. A majority of the present subjects (60%) had a preferred chewing side, but with few exceptions, subjects were unable to explain why a given side was preferred; explanations were only 'comfort' and 'habit' 2. The chewing, or working side was determined largely by the mean voltage of the surface electromyogram (EMG); in comparison with EMG from the non-wlring (contralateral) side, the working (ipsilateral) side showed a higher amplitude. 3. After the effort, the right masseter muscle is the most frequent site of pains, followed by the left masseter muscle, the anterior part of the right temporalis muscle and tile anterior part of the left temporalis muscle. 4. After the effort, mean voltages of masseter muscles were slightly increased, but mean voltages of temporalis anterior were slightly decreased at physiologic rest position. 5. No relationships could be established between preferred chewing side and side of initial muscle pains.

• Journal of Oral Medicine and Pain
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• v.26 no.4
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• pp.355-367
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• 2001

치의학 분야에서 디지탈 근적외선 체열측정 장치(digital infrared thermographic imaging; DITI)의 응용이 미미한 것은 과거 열측정장치의 기술력이 부족한 것이 주된 요인이었다. 그러나 최근들어 기술이 진보함에 따라 실시간 열영상을 재현할 수 있게 되었고 이는 치의학 및 의학계에 많은 관심을 일으키고 있다. 지금까지의 연구를 보면 두개하악장애시 구강영역의 온도변화의 임상적 효용 가능성을 제시하였으나 안면 및 두경부에 대한 실제 기기 및 측정방법의 신뢰도에 대한 연구는 이루어지지 못한 상태이다. 본 연구에서는 DITI에 대한 신뢰도를 조사하였다. DITI의 모니터 상에서 비활동성 발통점의 부위를 찾아내기가 쉽지 않다. 따라서 모니터상에서 안면발통점(joint, temporalis anterior, masseter anterior, masseter inferior)의 부위를 찾아 온도를 찾아내는 방법과 미리 발통점 피부상에 링모양의 마크를 부착하여 모니터상에서 쉽게 찾아내는 방법을 사용하여 신뢰도를 조사하여 비교한 결과 다음과 같다. 1. 조사한 발통점 중에서 temporalis anterior, joint, masseter anterior과 masseter inferior의 순서로 피부온도가 유의하게 온도가 높았으나(p<0.05) masseter 내에서는 유의한 차이를 보여주지 않았다. 2. 4개의 발통점 모두에서 높은 열적 대칭성을 보였으며, 좌우 온도차이는 $0.1^{\circ}C$미만이었다. 3. 다른 시기에 조사한 조사자내 신뢰도는 두 조사자 모두 높은 상관관계를 보여주지 않았으며 대조군과 마크를 사용한 군간에는 뚜렷한 차이를 볼 수 없었다. 4. 동일한 시기에 조사한 조사자간 신뢰도는 두 시기 모두 joint 부위의 일부를 제외하고 높은 상관관계를 보여주었으며, 마크를 사용한 경우 사용하지 않은 경우 보다 훨씬 신뢰도가 높은 상관관계를 나타내었다. 이상의 결과로 보아 DITI는 두개하악장애환자에 대한 두경부 발통점의 온도변화를 측정하는 데 있어 시간에 따른 신뢰도는 결여되었으나 동일 시기의 측정에는 매우 유익할 것으로 사료되며, 특히 발통점에 대한 표시를 사용하는 경우 매우 정확한 온도를 조사할 수 있을 것으로 판단된다.