• The Journal of the Korean dental association
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• v.12 no.2
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• pp.123-129
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• 1974

The electrical activities of masseter muscle were recorded on 9 subjects with unilateral fracture of mandible. The electromyographic studies were executed with 2 channel RS dynograph recorder for electromyography. The graphs were recorded in the physiologic rest position, incisal occlusion, molar occlusion, left lateral excursion, right lateral excursion, and protraction. The following conclusions were drawn; 1. In the physiologic rest position, incisal occlusion, molar occlusion, and protraction, the electrical potentials of the masseter muscle were greater in the affected side. 2. In the right lateral excursion, the electrical potentials of the masseter muscle were greater in the right side, and in the left lateral excursion, greather in the left side. There is no correlation mutually between the affected side and unaffected side.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.4
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• pp.358-361
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• 2001

We had experienced a case of traumatic myositis ossificans arising in right masseter muscle, inferior to zygomatic arch occurred on 25 year old male. He had some trauma on the site one year ago and visited with complaint of mouth opening limitation and swelling. Palpable mass with facial disfigurement was noted. and several ovoid radiopaque masses were revealed on C.T. examination. On histopathologic examination, multiple bone trabeculae with osteoblasts in its periphery was noted in connective tissues and invaded to neighbouring muscles, but any chondroid components were not revealed.

• 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.

• The Korean Journal of Pain
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• v.8 no.1
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• pp.86-92
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• 1995

Temporomandibular disorders typically present findings of limited or asymmetric patterns of jaw opening and joint sounds usually described as clicking, popping, grating, or crepitus. Recently, patients with temporomandibular disorders have received an increasingly aggressive treatment with a greater emphasis on surgical and dental reconstruction. Scientific studies have not clearly identified the specific causes of the temporomandibular disorders and therefore some of the treatments are empiric, without a firm scientific foundation. We carried out a study on the patients of pain clinic OPD and concluded that the causes of the temporomandibular joint(TMJ) pain are the prolonged contraction of the muscles of mastication, especially the masseter muscle. Therefore, the spasmolytic treatment of masseter muscle would be a better treatment for TMJ syndrome rather than the surgical and dental reconstruction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.423-426
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• 2010

Hemangioma is a benign vascular proliferation. Intramuscular hemangiomas are rare, accounting for less than 1% of all hemangiomas, and occur normally in the trunk and extremities. Approximately 10-20% of intramuscular hemangiomas are found in the head and neck region, most often in the masseter muscles. The typical clinical characteristic is a painful soft tissue mass without cutaneous changes. The suggested treatment is a surgical excision. We report a case of an intramuscular hemagnioma of the masseter muscle. The patient was a 56 year old male who visited our clinic complaining of left facial swelling after 2 years of follow up at a different clinic. After magnetic resonance imaging (MRI), the mass was excised under general anesthesia. The biopsy revealed the mass to be an intramuscular hemangioma. We report the clinical and pathological characteristics as well as the treatment of a case of an intramuscular hemangioma of the masseter muscle.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.269-281
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• 1995

To study the characteristics of EMG power spectrum of masticatory muscles during sustained isometric contraction and recovery at various contraction times, the author analysed the EMG signals of anterior temporal and masseter muscles before, during, and after sustained isometric contraction at 50% level of maximum voluntary contraction (MVC) for 15,30,60 seconds. Twelve normal subjects were included in this study. The author came to following conclusions from the results. 1. MMF of anterior temporal muscle in the contraction period was significantly higher than that of masseter muscle during sustained isometric contraction regardless of isometric contraction times (p<0.05). 2. MMF in the contraction period decreased as the contraction time increased during sustained isometric contraction in both temporal and masseter muscles(p<0.05). 3. SMF in the contraction period increased as the contraction tie increased during sustained isometric contraction in both temporal and masseter muscles(p<0.01). 4. MMF in the first part of recovery period (20 seconds) decreased as the contraction time increased during sustained isometric contraction(p<0.05). However, MMF in the later parts of recovery period (20-120 seconds) showed no significant differences. 5. MMF of anterior temporl muscle in the recovery period was significantly higher than that of masseter muscle after sustained isometric contraction regardless of isometric contraction times (p<0.05). 6. The recovery rate of MF reached 100% in 100 seconds after the isometric contraction regardless of isometric contraction times.

• The korean journal of orthodontics
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• v.47 no.4
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• pp.222-228
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• 2017

Objective: To evaluate soft- and hard-tissue changes in the mandibular angle area after the administration of botulinum toxin type A (BoNT-A) injection to patients with masseteric hypertrophy by using three-dimensional cone-beam computed tomography (3D-CBCT). Methods: Twenty volunteers were randomly divided into two groups of 10 patients. Patients in group I received a single BoNT-A injection in both masseter muscles, while those in group II received two BoNT-A injections in each masseter muscle, with the second injection being administered 4 months after the first one. In both groups, 3D-CBCT was performed before the first injection and 6 months after the first injection. Results: Masseter muscle thicknesses and cross-sectional areas were significantly reduced in both groups, but the reductions were significantly more substantial in group II than in group I. The intergonial width of the mandibular angle area did not change significantly in either group. However, the bone volume of the mandibular gonial angle area was more significantly reduced in group II than in group I. Conclusions: The repeated administration of BoNT-A injections may induce bone volume changes in the mandibular angle area.

• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.19-25
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• 1992

The pressure pain thresholds of head and neck muscles of patients suffering from tensiontype headache220, all female, ages ranged from 13 to 50 years (28.4$\pm$9.6) and 39 healthy controls, all female, ages ranged from 14 to 46 years (24.4$\pm$9.2) were recorded by the electronic algometer (Electyronic Algometer Type I, Somedic, Stockholm, Sweden). And the obtained results were as follows : 1. The pressure pain thresholds of patient group were lower than those of controls in superior sternocleidomastoid muscle, middle sternocleidomastoid muscle, and trapezius insertion muscle (P<0.001) 2. The pressure pain thresholds of patient group were not different from those of controls in anterior temporal, middle temporal, posterior temporal, deep masseter, anterior masseter, inferior masseter, medial pterygoid, posterior digastric, splenius capitus and upper trapezius muscle (P>0.05). 3. Seventy-one percent of tension-type headache patients had more than one muscle, of whicb pressure pain threshold was lowered significantly (less than mean of control - 1.5SD). 4. The pressure pain thresholds of head and neck muscles should be considered as a criterion for the diagnosis of tension-type headache.

• Journal of Oral Medicine and Pain
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• v.12 no.1
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• pp.41-46
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• 1987

In order to study of muscle fiber proportion of masticatory muscle, 6 rabbits masticatory muscles (masseter, temporal, internal pterygoid, external pterygoid) were excised. Muscle specimens were fixed in 10% neutral buffered formalin fixer and sectioned $5{\mu}$ for PAS staining. With the light microscopic photograph the proportion of muscle fibers of each muscle were computed. The results were as follow; 1. Average classical red fiber proportion of rabbit masticatory muscles was 85.7% 2. Masseter muscle revealed 90.3% of classical red fiber in the rabbit masticatory muscles.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.4
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• pp.174-179
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• 2019

Patients with masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) experience limited mouth opening due to restricted muscle extension. Hyperplastic aponeurosis and tendons lead to the restriction of muscle extension. The criteria for the diagnosis of MMTAH are limited mouth opening that progresses very slowly from adolescence, intraoral palpation reveals a hard cord-like structure along the overhang of the anterior border of the masseter muscle on maximum mouth opening, and a square mandible. Conservative treatment, including pharmacotherapy, occlusal splint and physical therapy are ineffective. The standard therapy is surgical treatment, such as anterior partial aponeurectomy of the masseter muscle and coronoidectomy. The long-term results are very satisfying.