Background: For the rehabilitation of stroke patients, it is necessary to confirm the differences in the mechanical properties of the paretic- and non-pareticside masseter muscles. Objectives: To investigate the muscle tone and stiffness of masseter muscles in patients with chronic stroke. Design: A case study. Methods: This study included 20 stroke patients. Muscle tone and stiffness of the paretic and non-paretic masseter muscles in stroke patients were measured using MyotonPRO. Measurements were performed under relaxation and masseter muscle contraction conditions. Results: There was no significant difference in the muscle tone and stiffness of the paretic and non-paretic side masseter muscles in the relaxation conditions (P>.05). In male, left hemiplegia, right hemiplegia and infatction, the nonparetic side masseter muscles showed significantly increased than musle tone and stiffness of the paretic side masseter muscles in the contraction (P<.05). In female and hemorrhage, the non-paretic side masseter muscles showed significantly increased than musle tone the paretic side masseter muscles in the contraction (P<.05). Conclusion: The muscle tone and stiffness were lower on the paretic side than on the non-paretic side during masseter muscle contraction in stroke patients; thus, muscle strengthening training was required.

Background: For the elderly, masticatory function is one of the most important oral functions and the masticatory ability is related to the wearing of dentures. Many older people wear dentures for their masticatory function, but a significant number of older people who use dentures have found that they feel uncomfortable when performing their daily activities, such as performing masticating functions or talking. Objects: The purpose of this study is to investigate how the forward head posture (FHP), respiratory function and thickness of masseter (MS), and sternocleidomastoid (SCM) are affected by the presence or absence of dentures in the elderly, and what kind of correlation there is between these variables. Methods: The study was conducted on 11 patients in the normal group and 13 in the denture group. The participant’s cognitive ability was evaluated using Mini-Mental State Examination Korean (MMSE-K), and the FHP was evaluated by measuring the craniovertebral angle (CVA). The thickness of the MS and SCM muscles were measured using ultrasound, and respiration was measured with a spirometry. As for the statistical method, the correlation of each variable was investigated using Spearman’s correlation coefficient. Results: In the normal group, there was a significant correlation between forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) (p < 0.001), and in the denture group, FVC and FEV1 (p < 0.001), maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) (p < 0.001), CVA and Lt. MS (p = 0.012). Conclusion: CVA and Lt. MS of the denture group have a high negative correlation, it is related that the thickness of MS may be thick when the elderly wearing dentures are FHP.

Background: Patients with dysphagia after stroke are treated with neuromuscular electrical stimulation (NMES), but its effect on masseter muscle thickness and bite force in the oral phase is not well known. Objectives: To investigated the effect of NMES on masseter muscle thickness and occlusal force in patients with dysphagia after stroke. Design: Two group, pre-post design. Methods: In this study, 25 patients with dysphagia after stroke were recruited and allocated to either the experimental or the control groups. Patients in the experimental group were treated with NMES to the masseter muscle at the motor level for 30 minutes and were additionally treated with traditional swallowing rehabilitation for 30 minutes. In contrast, patients in the control group were only treated with traditional swallowing rehabilitation for 30 minutes. Masseter muscle thickness was measured using ultrasonography before and after intervention, and bite force was measured using an bite force meter. Results: The experimental group showed significant improvement in masseter muscle thickness and bite force compared to the control group. Conclusion: NMES combined with traditional dysphagia rehabilitation is effective in improving masseter muscle thickness and bite force in patients with dysphagia after stroke.

Pseudosarcomatous fibromatosis (PSF), also known as nodular fasciitis and pseudosarcomatous fasciitis, is a rare, benign proliferation of fibroblasts and myofibroblasts. It is often misdiagnosed as sarcoma because of its characteristic rapid progression, leading to unnecessary and aggressive surgery. Here we report a case of PSF found in the masseter muscle in a 26-year-old female. The mass that could be misdiagnosed because of its rapid growth characteristics was surgically excised by an intraoral approach and diagnosed as PSF by histopathologic examinations.

Background: Temporomandibular disorder (TMD) is characterized by pain and limited range of motion in the jaw. TMD patients generally prefer to chew on the unaffected or less-affected side, and this tendency often results in asymmetries in masseter muscle thickness and range of mandibular motion. Objects: The purpose of this study was to compare the asymmetries in masseter muscle thickness and range of mandibular motion in subjects with and without temporomandibular disorders. Methods: Thirty-nine subjects were divided into two groups: A TMD group (n1=19) and a control group (n2=20). The jaw opening range and laterotrusion were measured using a digital vernier caliper. The masseter muscle thickness was examined in both the resting state and the maximal clenching state using ultrasonography. The absolute asymmetry indices calculated based on the laterotrusion and masseter muscle thickness of the respective right and left sides. A two-way ANOVA and a Mann-Whitney U test were used for statistical analysis. Results: No significant different was found in the masseter muscle thickness between the TMD and control group. A significant difference was found in the absolute asymmetry indices of mandibular laterotrusion between the TMD and control groups (p<.05). Furthermore, the ranges of jaw opening were significantly different between males and females (p<.05). The absolute asymmetry index values of masseter muscle thickness at rest and during maximal clenching were also significantly different between males and females (p<.05). Conclusion: These results demonstrated that the subjects with TMD had a larger degree of asymmetry in laterotrusion than those without TMD. Therefore, a physiotherapy program needs to be designed to restore normal laterotrusion capacities for TMD subjects. These results also showed that female subjects had greater absolute asymmetry indices in masseter muscle thickness than male subjects. Therefore, more training is needed to promote bilaterally balanced chewing among women.

Schwannoma, benign neoplasia derived from schwann cell, is rare tumor, and prevalent in tongue, palate, floor of mouth and buccal mucosa. Thirty-six-year-old male with asymptomatic protrusion of mandible angle was evaluated. We surgically removed the mass and histological examination gave the diagnosis of ancient schwannoma. We report a case of ancient schwannoma in masseter muscle and review of literature.

The purpose of this study is to identify the level of masseter muscle tension according to the levels of restricted movement and pain in the temporomandibular joint(TMJ), thereby verifying the fact that excessive masseter muscle tension can be a cause for restricted movement and pain in the TMJ. The subjects of this study were 81 men and women in their 20s and 30s, who feel uncomfortable with their masticatory function on the preferred chewing side. The subjects were measured in terms of the range of motion (ROM) and deviation of the TMJ and the degree of pain in the affected region. The ROM and deviation of the TMJ were measured using the Global Posture System(GPS) after instructing each subject to open his/her mouth to the fullest and taking photos of the subject with a digital camera. The tension of the masseter muscle was measured with a Pressure Threshold Meter(PTM). After the measurements, in order to compare the ROM of the TMJ, the subjects were divided into two groups based on the ROM of above 35mm and below 35mm. For the deviation and pain, based on the average of total subjects, the subjects were divided into two groups of above and below average. Thereafter, the levels of masseter muscle tension were compared between each pair of groups. According to the results, when each variable was compared between the respective two groups, in terms of the deviation, the pressure pain threshold(PPT) of the masseter muscle revealed a statistically significant difference(p<.05). However, the ROM and pain showed no statistically significant difference. Consequently, masseter muscle tension may cause restricted movement in the TMJ. In particular, the deviation and tension in the masseter muscle is considered to be a factor that causes deviation in the TMJ.

본 연구는 조선후기 실학의 한 양상을 보여준다고 평가되는 五洲衍文長箋散稿의 구성상의 특징을 살피고, 이와 관련하여 五洲 李圭景(1788-1856)의 공부법 가운데 하나를 밝힘으로써 조선후기 일부 지식인들에게 보이던 지적 풍토를 究明하는 것을 목적으로 한다. 이 과정에서 다음 사항들이 검토되었다.첫째, 기존에 알려진 五洲의 작품 五洲衍文長箋散稿 五洲書種 詩家點燈 이외에 五洲의 손에서 이루어진 다른 서적이 있는가를 검토하였다. 五洲衍文長箋散稿에 대한 분석만으로도 이상 3종 이외에 약 20여종의 서적이 五洲의 저작임을 확인할 수 있었다. 둘째, 그렇다면 이 많은 저작들을 남길 수 있었던 것은 어째서인가? 이는 무엇보다 五洲衍文長箋散稿에서 보이는 構成上의 문제를 염두에 두지 않을 수 없다. 즉, 이 책은 일정한 주제에 관해 沈潛된 사고를 바탕으로 저자의 견해를 피력하는 데에 주안을 두었다기보다는, 일정한 주제에 관해 기존의 관련정보들을 갈무리해두는 방식을 택하고 있다. 다시 말해, 짧은 기간에 많은 저작을 남긴 것은 오히려 깊이 있는 沈潛이 결여된 成冊 방식이 큰 몫을 한 듯 하다. 셋째, 정보를 갈무리하는 성책방식은 단순한 독서를 통해 이루어진다기보다는 해당 정보를 직접 ‘보유’하고 있을 필요가 있다. 이 과정에서 크게 활용된 공부법이 바로 抄였으며, 抄는 抄하는 과정에서 정보의 습득을 가져오지만 또 다른 측면으로 보자면 정보의 구축, 즉 성책의 수단이기도 하였다. 따라서 五洲衍文長箋散稿라는 책은 五洲가 지녔던 癖에 가까운 抄라는 공부법이 이루어낸 결과물이라는 것을 알 수 있었다.

Most Authors reported that mouth guard is a part of equipment for body-contact sports players. Mouth guards protect orofacial injuries but have some problems in breathing and speaking. Some authors reported that mouth guards have also improve the muscle strength and sport ability. This experiment was performed to study the change of masseter muscle EMG after wearing of mouth guard. 10 D university male base ball players were participated in this study. After impression taking, mouth guards were constructed and weared. Masseter muscle EMG and nasal ventilation after ten day's adaptation were checked. They were requested clenching with or without mouth guard. EMG and nasal ventilation were checked by iworx 104 instrument simultaneousley. The result showed that masseteric EMG were improved and nasal ventilation were stable after wearing mouth guard. It concluded that mouth guard had improved muscle activity and stabilized the nasal ventilation depend on experimental method.