• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.2
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• pp.131-135
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• 2004

The purpose of this study was to evaluate the resistant force of medial pterygoid muscles against the mandibular advancement and distraction to anterior, and inquire into the relationship between medial pterygoid muscles and cephalometric variables. Sixty six patients with class III malocclusion underwent bilateral sagittal splitting of ramus with intraoralvertico-sagittal ramus osteotomy for mandibular set-back. The spring scale was used to measure the resistance of medial pterygoid muscles after splitting of ramus. Skeletaldental cephalometric analysis was made and statistic package was used for correlation between resistance and cephalometric variables. The resistant force of the right medial pterygoid muscle was greater than the left one in Koreans with class III malocclusion, and the force had a linear regression relationship with facial depth. The results suggested that facial depth has significant correlation with the resistance of medial pterygoid muscle, which can be acquired from patient's cephalometric analysis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.5
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• pp.313-320
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• 2020

Objectives: The aim of this study was to evaluate the relationship between masticatory muscle thickness and mandibular morphology in young Korean adults with normal occlusion and mandibular prognathism. Patients and Methods: Multidetector computed tomography (MDCT) was used to measure the masticatory muscle thickness on the right side in 100 Korean young adults (50 normal occlusion group, 50 mandibular prognathism group). Cephalometric analysis was done to measure mandibular morphology. Pearson correlation analysis was done to investigate the relationship between the masticatory muscle thickness and mandibular morphometry. Results: The four masticatory muscles showed positive correlation with intergonial width in all subjects. All muscles, except temporalis, positively correlated with height of the ramus and mandibular length. Positive correlation was also observed in all muscles, except medial pterygoid, with thickness of the ramus. In the normal occlusion group, all four masticatory muscles showed positive correlation with intergonial width and ramus thickness. Positive correlation was also observed in all muscles (except lateral pterygoid) with mandibular length. Masseter and lateral pterygoid positively correlated with height of the ramus. In the mandibular prognathism group, all masticatory muscles, except lateral pterygoid, showed positive correlation with intergonial width. The masseter muscle showed negative correlation with ANB. Conclusion: The results suggest a positive correlation of the thickness of masticatory muscles with both horizontal and vertical dimensions of the mandible. However, thickness of the masseter was found to decrease in patients with increasing severity of mandibular prognathism.

• Korean Journal of Head & Neck Oncology
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• v.10 no.2
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• pp.128-136
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• 1994

Maxillary cancer is usually detected late, and the majority of patients have advanced($T_3\;or\;T_4$) diseases at the first diagnosis. It invades outside the maxillary antrum, superiorly the orbit, ethmoid sinus and the anterior cranial base, anteriorly the facial skin. If the cancer extends through the posterior antral wall, the pterygoid plates, pterygoid muscles and infratemporal fossa are to be involved that make the conventional maxillectomy impossible to remove all the involved structures in infratemporal fossa completely. So, more extensive surgical apprdoach is necessary. We report surgical experience using infratemporal fossa approach(lateral facial approach) in four cases of maxillary cancer and one case of hard palate cancer which extends through the posterior antral wall and involving pterygoid muscles, pterygoid plates and temporalis muscle.

• 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.

• Korean Journal of Cleft Lip And Palate
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• v.4 no.2
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• pp.45-50
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• 2001

Recents reports have demonstrated that force and direction is important during mandibular distraction osteogenesis. The purpose of this study was to evaluate the resistant force of internal pterygoid muscles and inquire into relationship between internal pte'Ygoid muscles and cephalometric parameters. Eighty four patients with class III malocclusion underwent bilateral sgittal splitting of ramus with intraoral vertico-sagittal ramal osteotomy. A spring scale were used for measuring for resistence of internal pterygoid mescles after splitting of ramus. Skeletal-dental cephalometric analysis was made following statistic package was used for correlation between resistence and cephalometric parameters. The resistant force of right internal pterygoid muscle was greater than left muscle in Korean with class III malocclusion and the force had a linear regression relationship with facial depth (distance between nasion and gonion). The results suggested that facial depth has significant correlation of the resistance of internal pterygoid muscle (p<0.05).

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.31-34
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• 2004

Purpose: To compare the size of the masseter and lateral pterygoid muscle between the affected and the unaffected side of the patients who have the chief complaints of the mandibular asymmetry. Materials and Methods: Twenty two patients (male: 4, female: 18, average age: 21.3 year-old) were radiographed using posterior-anterior (P-A) cephalography and computed tomography (CT). On P-A cephalography, the degree of deviation was determined by the distance from the mentum to the vertical reference line through the crista galli and the anterior nasal spine. On the scanned tracing papers of the maximum cross-sectional area of the masseter and lateral pterygoid muscle using axial CT images, the pixel number was measured. The ratio of the affected : unaffected sides were obtained. For the masseter and lateral pterygoid muscle, the relationship between the muscular volume and degree of skeletal hypoplasia was studied. Results : The half cases showed no skeletal asymmetry. The lateral pterygoid muscle of the affected side was larger significantly than unaffected side (p<0.05). However, there was no significant difference between two sides in the cases of skeletal asymmetry. There was only significant difference in the cases without skeletal asymmetry (p<0.05). Conclusions : To some extent, the slight mandibular hypoplasia could affect the growth of some masticatory muscles.

• Journal of Oral Medicine and Pain
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• v.35 no.4
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• pp.275-281
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• 2010

The lateral pterygoid muscle is one of the masticatory muscles basic to jaw function. Because of its deep location in the masticatory system, digital palpation of the muscle is usually difficult to perform and unreliable. Therefore, diagnosis of the myalgic disorders involving the lateral pterygoid muscle is a perplexing problem for clinicians. Local anesthetic injection can be a more effective method to examine the lateral pterygoid muscle for the purpose of discriminating the source of pain. Furthermore, immediate elimination of muscle pain facilitates stretching of the muscle in the full range. We report two cases of lateral pterygoid myalgia that were diagnosed and managed successfully through the use of intramuscular local anesthetic injection.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.1_2
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• pp.146-153
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• 1992

In the outpatient clinic, we have many patients who suffer from temporomandibular joint disorders. These vary from MPD syndrome to osteoarthrosis, and many cases have tender spots or areas on the temporomandibular joint region and/or masticatory muscles. Further, they frequently have masticatory muscle pain when opening the jaw. This paper presents the results of our research on the differential diagnosis for tendernesses and pain on opening the jaw in the temporomandibular joint region and the masticatory muscles by joint cavity pumping with local anesthestic. The areas of tenderness and jae-opening paw in 65 patient suffering from temporomandibular joint disorder were examined and recorded before and after anesthetizing the upper joint cavity with 2% lidocaine. Maximum interincisal distance was similarly recorded. The results were as follows : In the area surrounding the upper joint cavity including the lateral pterygoid muscle, the tenderness and jaw-opening pain vanished almost entirely after anesthesia. This was considered a direct infiltrative effect of the local anesthesia. After the anesthesia, 86% of the tendernesses on the sternocleidomastoid muscles, and 66% of those on the posterior belly of the diagstric muscles vanished, while the disappearance rates on the masseter, temporal, and medial pterygoid muscles were 50~60%. Apart from the temporomandibular region, pain on opening the jaw was found on the masseter, temporal, posterior belly of the digastric muscles, and medial pterygoid muscles before anesthesia. The disappearance rates after anesthesia were 90~100% except for the pain of the posterior belly of the digastric muscles, for which the rate was 66%. These results suggest that more than 88% of the tendernesses on the sternocleidomastoid muscle, more than 60% of the tendernesses and jaw-opening pains on the digastric muscle, and more than half of the tendernesses and almost all of the jaw-opening pains in the jaw-closing muscles are referred pains from the temporomandibular joint. The tendernesses that had no change after anesthesia were considered to be derived from spasms of the muscles proper. Generally, maximum interincisal distance increased after anesthesia. The average distance was 34mm before anesthesia, but increased to 41mm after anesthesia. In a few cases, however little or no change was found in those distances. In these cases, pathological changes were found in the joint cavities arthrographically or arthroscopically.

• Journal of Oral Medicine and Pain
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• v.37 no.4
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• pp.227-231
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• 2012

Localized myositis ossificans is a disease with the main feature of formation of heterotropic bone and fibrous tissue involving muscle. It also called traumatic myositis ossificans. Myositis ossificans is likely to occur in the femoral region or brachium but, rarely in the head and neck including the masticatory muscles. It arises from traumatic episodes caused by prolonged mouth opening, surgical procedure, local anesthesia injection. The main clinical feature is the mouth open limitation. The diagnosis of myositis ossificans is usually based on the patient's history, clinical symptoms and on imaging finding. We present the case of patient with localized myositis ossificans of the temporal and lateral pterygoid muscles.

• Journal of Oral Medicine and Pain
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• v.38 no.2
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• pp.149-159
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• 2013

The purpose of this study was to investigate the relationship between horizontal morphology of lateral pterygoid muscle and onset of temporomandibular joint disorders. Randomly selected 150 subjects, assigned with equal number in terms of gender and age group, were included. The axial and sagittal images in their magnetic resonance images of the temporomandibular joints were used to measure the morphologic characteristics of lateral pterygoid muscles and temporomandibular joints. The measurement variables were maximal horizontal width and insertion angle to the condyle, position of the articular disc, condylar deformity, and joint effusion. In addition, presence or absence of the temporomandibular joint pain was examined through history and palpation of the joints. The relationships among measurement variables were analyzed and the results were as follow. The insertion angle of the lateral pterygoid muscle to the condyle was higher in the joint of anterior disc displacement without reduction than that in the joint of normal disc position. In addition, the maximal horizontal width of the lateral pterygoid muscle was significantly increased in joints with pain than those without pain. Also, the insertion angle was significantly higher in younger age group and the maximal width was significantly greater in male than in female. These results suggest that high insertion angle of lateral pterygoid muscle might be an important anatomic predisposing factor for anterior disc displacement in temporomandibular joint and muscular activity of lateral pterygoid muscle might be affected by preauricular pain. In conclusion, there might be a bi-directional interaction between lateral pterygoid muscle and joint in the progression of anterior disc displacement in temporomandibular joint.