• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1677-1679
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• 2002

This experiment was carried out to evaluate the tenderness of meat and it''s correlation with other carcass traits of Hanwoo steers. The significantly (p<0.01) higher mastication and shearing were observed in boiled meat than in the raw meat but the coefficient of variations were greater in raw meat than in boiled meat. The correlation between raw and boiled meat for shearing and penetration were positive and significant (p<0.01). Negative and significant correlations were observed between mastication and eye muscle area (p<0.05) and also between shearing and cooking loss (p<0.01) in raw meat whereas, penetration in raw meat was positively and significantly (p<0.05) correlated with age of the steers. Shearing in boiled meat negatively and significantly correlated with age (p<0.05), carcass weight (p<0.01), back fat thickness (p<0.01) as well as muscle score (p<0.01). The pH was not significantly correlated with tenderness in both raw and boiled meat. There were possibilities that the tenderness of boiled meat could be predicted from the raw meat.

• Journal of Oral Medicine and Pain
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• v.18 no.1
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• pp.55-62
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• 1993

The author has synchronously recorded the average electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muacles and the masseter muscles. The marious levels of occlusal force were checked during clenching the resin plates which are made to fit each of the maxillary and the mandibular teeth. These activities were recorded in order to study the EMG activity pattern of the sternocleidomastoid muscle during the masticatory function of the jaw in 11 healthy subjects. The obtined results were as follows : 1. The electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muscles and the masseter muscles were increased as the occlusal force increased, and the sternocleidomastoid muscles have a lineal correlationship with the occlusal force. 2. The sternocleidomastoid muscles and the masseter muscles showed higher EMG activity during clenching at the ventroflexed head position rather than at the extended head position. (p<0.05) However the EMG activities of the anterior temporal muscles showed no difference between the ventroflexed position and the extended position of the head. 3. The electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muscles and the masseter muscles during clenching are similar at the habitual position and at the retruded condylar position. 4. The electromyographic activities of the sternocleidomastoid muscles, the anterior temporal muscles and the masseter muscles on the working side during mastication of gum and almonds are significantly higher than on the balancing side except the masseter muscles during mastication of almonds. (p<0.05, P<0.01) 5. The asymmetry of gum are lower than that during mastication of almonds. (p<0.05) The asymmetry indices of the sternocleidomastoid muscles are higher than those of the anterior temporal muscles and masseter muscles.

• Journal of Korean society of Dental Hygiene
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• v.19 no.5
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• pp.743-752
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• 2019

Objectives: Grip strength is a measure for assessing overall muscle strength, muscle mass, and nutritional status, and is a useful tool for early examination of a person's general health. Thus, this study analyzed the association between oral health-related factors and grip strength, using the 6th Korea National Health and Nutrition Examination Survey (KNHANES) data. Methods: Data were analyzed using the IBM SPSS version 25.0 (IBM Co., Armonk, NY, USA) software with a complex sampling analysis of stratified and clustered variables, all with weighted values, applied for every analysis conducted. From the 6th KNHANES data, a total of 26,101 people were selected as the study population. A complex sample generalized linear model analysis was performed for participants' sociodemographic characteristics, health status, use of oral care products, and factors such as adult mastication and speaking habits. Results: Grip strength was found to be higher among men compared to women. Grip strength was the highest in the 20-39 year old group. Furthermore, grip strength was statistically significantly higher among married and employed individuals, and in the right hand (p<0.001). Grip strength was statistically significantly higher among people who perceived themselves to have good health and among those who did not have health-related problems in the past two weeks (p<0.001). It was also higher among those who used interdental brushes and electronic toothbrushes (p<0.001), but decreased with greater discomfort in mastication and speaking among adults (p<0.05). Conclusions: Grip strength was found to be associated with oral health-related factors and therefore, these could be helpful tools in evaluating both general and subjective health statuses. In general, oral care products are small in size with oral care involving the use of hands and certain precise motions and actions to remove foreign substances in the oral cavity. As shown in the findings, grip strength declines with increased age and as a result, the use of oral care products should be strongly recommended in order to promote better general health.

• Journal of Oral Medicine and Pain
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• v.8 no.1
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• pp.43-60
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• 1983

In order to obtain the basic data for diagnosis of occlusion the author investigated the occlusal sounds produced by mandibular closing movement from rest position to centric occlusion by using the Korotkoff sounds microphone electrodes and physiograph for Korean 20S without TMJ problems. And the author analyzed the correlation of the occlusal sounds with height, body weight, mandibular closing movement distance, maxillary sinus size and masseter muscle activities relating to the production of occlusal sounds. The obtained results were as follows : 1. The occlusal sounds prouduced by mandibular closing movements from rest position to centric occlusion were ranged from 3.08mV to 52.00mV, their maen value 19.07mV in right side, and ranged from 2.41mV to 18.33mV, their mean value 9.19mV in left side in group of Angel's class I occlusion subjects having right habitual side of mastication. 2. In general the occlusal sounds in the habitual side of mastication were greater than those in the opposite side. 3. The correlations of the occlusal sounds with height and maxillary sinus size were not significant. 4. The correaltions of the occlusal sounds with body weight, mandibular closing movement distance and masster muscle activities were significant.

• Journal of Oral Medicine and Pain
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• v.12 no.1
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• pp.53-61
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• 1987

In order to evaluate the effect of unilateral tooth clenching, the author observed a feature of producing the symptom complex related to pain and discomfort by the isometric unilateral canine biting under force of 5kg(FS) in Korean 31 adult females within normal masticatory function who were divided into the bilateral, the right and the left group according to their habitual sides of mastication, and analyzed the observed data statistically. The obtained results were as follows: 1. The duration of the isometric unilateral canine biting maintained before the occurrence of symptom complex related to pain and discomfort 66.72 seconds at right side and 39.50 seconds at left side in a group of subjects with bilateral habitual mastication. And the difference of the duration between of unilateral biting side was almost significant (P<0.05). 2. The most frequent region of occurrence of symptom complex related to pain and discomfort by the isometric unilateral canine biting was the contralateral superficial masseter muscle in a group of subjects with bilateral habitual mastication.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.197-221
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• 1991

The purpose of the present study was to investigate the differences of EMG activity of the masticatory muscles between normal occlusion and Class III malocclusion during various jaw functions. 46 subjects of 18.4-25.7 years were employed in this study: 26 subjects were normal occlusions, and 20 subjects were Class III malocclusions. The EMG data from the anterior and posterior temporal, anterior and posterior masseter muscles in both sides as mandibular elevators and supra-hyoid muscle group (close to the anterior belly of digastric muscle in right side) as mandibular depressor were recorded with the Medelec MS 25 electromyographic machine. The EMG recordings were analyzed during mandibular rest position, maximal biting, mastication with chewing gum, and swallowing of peanuts. All data were recorded and statistically processed. 1. The maximal mean amplitude of the anterior temporal muscle was stronger significantly in Class III malocclusion than in normal occlusion, and then the posterior temporal was weaker during mandibular rest position. 2. The maximal mean amplitudes in the anterior and posterior temporal muscles and the anterior masseter muscle of Class III malocclusion was weaker significantly than that of normal occlusion during maximal biting. 3. During mastication of the chewing gum, the maximal mean amplitudes of Class III malocclusion was weaker significantly than normal occlusion in the anterior and posterior temporal muscles of the working side, and the duration of Class III malocclusion was longer in the anterior temporal muscles of both aides, and the posterior temporal and the anterior masseter muscle of the balancing side. There were significant increasings of the latency in balancing anterior temporal, working posterior temporal muscles and supra-hyoid muscle group of Class III malocclusion. The silent period durations was 16.36 ms in Class III malocclusion while 10.76 ms in normal occlusion, which was statistically different (P < 0.05). 4. At swallowing of peanuts, the maximal mean amplitude of Class malocclusion was weaker significantly in the posterior temporal muscle than that of normal occlusion. There was no significant difference of duration between normal occlusion and Class III malocclusion. 5 The muscle activities of Class III malocclusion had a tendency of decrease less than normal occlusion. And then the muscle activities of the anterior temporal and anterior masseter muscles in Class III malocclusion showed the tendency of the increase more than other muscles of Class III malocclusion.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.218-226
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• 2012

PURPOSE. The purpose of this study was to propose finite element (FE) modeling methods for predicting stress distributions on teeth and mandible under chewing action. MATERIALS AND METHODS. For FE model generation, CT images of skull were translated into 3D FE models, and static analysis was performed considering linear material behaviors and nonlinear geometrical effect. To find out proper boundary and loading conditions, parametric studies were performed with various areas and directions of restraints and loading. The loading directions are prescribed to be same as direction of masseter muscle, which was referred from anatomy chart and CT image. From the analysis, strain and stress distributions of teeth and mandible were obtained and compared with experimental data for model validation. RESULTS. As a result of FE analysis, the optimized boundary condition was chosen such that 8 teeth were fixed in all directions and condyloid process was fixed in all directions except for forward and backward directions. Also, fixing a part of mandible in a lateral direction, where medial pterygoid muscle was attached, gave the more proper analytical results. Loading was prescribed in a same direction as masseter muscle. The tendency of strain distributions between the teeth predicted from the proposed model were compared with experimental results and showed good agreements. CONCLUSION. This study proposes cost efficient FE modeling method for predicting stress distributions on teeth and mandible under chewing action. The proposed modeling method is validated with experimental data and can further be used to evaluate structural safety of dental prosthesis.

• 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 Oral Medicine and Pain
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• v.20 no.1
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• pp.171-183
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• 1995

This study was carried out to investigate the relationship between tensed mandibular positions, muscle tenderness and EMG activity, respectively, and between range of motion of the neck and sternocleidomastoid muscle tenderness. Under stressful conditions, most of people take several types of behavioral patterns. Two of them observed frequently are clenching of teeth and grasping of fist. Prolonged clenching or grasping should increase electromyographic activity of associated muscle, especially muscles of mastication and neck muscles and will cause hyperfunction, dysfunction and muscle pain. So it is necessary to relate EMG activity with muscle pain. The author performed routine clinical examination in 47 patients with Temporomandibular Disorders, especially for presence or absence of muscle tenderness. Mandibular rest position was used as a baseline reference position and two more position in which EMG activity was taken were rest postion with grasping of fist and teeth clenching position. BioEMG of Biopak system (Bioresearch Inc, USA) was used for measuring of integrated EMG in masseter, anterior temporalis, anterior belly of digastic muscle and sternocleidomastoid muscle. To measure of the range of neck motion. CROM(Cervical-Range-of Motion, USA) was used. The obtained results were as follows : 1. EMG activity of all muscles except in masseter was higher in grasping of fist than those in rest position and there were significant correlation in EMG activity between the two position except in anterior belly of digastric muscle. 2. When comparing EMG activity between tender and non-tender muscle, all examined muscles did not show any significant difference. From this data, we could conclude that EMG activity was generally not changed with tenderness, of couse, it might be dependent with degree of muscle tenderness. 3. Number of tender points in examined muscles was also not significantly different between in patients with masticatory muscle disorders and in patients with internal derangement. 4. Cervical posture and range of motion of the neck was not differed significantly between in patients with and in patients without tenderness of sternocleidomastoid muscle.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.317-324
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• 2009

This study aimed to assess stiffness and elasticity of the masticatory muscle in the patients with the masticatory muscle pain using a tactile sensor and to investigate whether the masticatory muscle pain affects the facial expression muscles. From those who visited Department of Oral Medicine in Dankook University Dental Hospital, 27 patients presenting with unilateral muscle pain and tenderness in the masseter muscle (Ms) were selected (mean age: $36.4{\pm}13.8$ years). Exclusion criterion was those who also had temporomandibular joint (TMJ) disorders or any neurological pain. Muscle stiffness and elasticity for the muscles of mastication and facial expression was investigated with the tactile sensor (Venustron, Axiom Co., JAPAN) and the muscles measured were the Ms, anterior temporal muscle (Ta), frontalis (Fr), inferior orbicularis oculi (Ooci), zygomaticus major (Zm), superior and inferior orbicularis oris (Oors, Oori) and mentalis (Mn). t-tests was used to compare side difference in muscle stiffness and elasticity. Side differences were also compared between diagnostic groups (local muscle soreness (LMS) vs myofascial pain syndrome (MPS) and between acute (< 6M) and chronic ($\geq$ 6M) groups. This study showed that Ms and Zm at affected side exhibited significantly increased stiffness and decreased elasticity as compared to the unaffected side.(p<0.05) There was no significant difference between local muscle soreness and myofascial pain syndrome groups and between acute and chronic groups. The results of this study suggests that masticatory muscle pain in Ms can affect muscle stiffness and elasticity not only for Ms but also for Zm, the facial expression muscle.