• Journal of Oral Medicine and Pain
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• v.48 no.4
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• pp.159-168
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• 2023

Purpose: Coordinated activity between the jaw and neck muscles is important in oral motor tasks such as chewing. This study examined coherence between the jaw and neck muscles during chewing in healthy adults. Methods: A total of 12 healthy adults underwent electromyography (EMG) of the jaw and neck muscles during right-sided chewing at a frequency of 1 Hz. Surface electrodes were placed over the temporalis (TA), masseter (MS), anterior digastric (DA), and sternocleidomastoid (SM) muscles on the right side. EMG signals were processed for coherence and phase analysis using advanced signal processing techniques. Results: The MS and TA muscle pair exhibited high synchronization when chewing (median coherence=0.992). Contrarily, the coherence values between the MS and DA, as well as the MS and SM muscle pairs, were relatively low (median coherence=0.848 and 0.957, respectively). Phase analysis revealed minimal temporal differences between the MS and TA muscle pair and the MS and SM muscle pair, whereas substantial phase shifts were observed between the MS and DA muscle pair. Conclusions: During chewing in healthy adults, the TA muscle works synergistically whereas the DA muscle antagonistically with the MS muscle, and the SM muscle supports the activity of the MS muscle. The observed synchrony and coordination provide insights into the intricate interplay among these muscles during oral motor tasks.

• 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 the korean academy of Pediatric Dentistry
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• v.23 no.3
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• pp.717-728
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• 1996

The effects of electro-acupuncture on the pain threshold and the amplitude of dEMG(di-gastric EMG) evoked by the noxious electric stimulation on teeth and gingiva in dogs were studied. Experiments were carried out with 10 dogs weighing 5-8kg. Each animal was anestheticed with Entobar given intraperitoneally in an initial dose of 30mg/kg. Maintenance dose of 5mg/kg/hr was given through a cannula, in the femoral vein, as required to keep up light anesthesia. Bipolar stimulating wire electrodes, 0.1mm in diameter, insulated except for tips, were inserted into the upper canine and palatal gingiva. Rectangular aluminium plate electrodes (15$\times$5mm) were placed on acupuncture points, called Yin-Hsiang, located at both sides of the upper jaw. Rectangular biphasic current pulses of 2Hz, with a $250{\mu}sec$ duration, were delivered for 15 minutes. The dEMG activities were recorded from the anterior belly of the digastric muscle(one of the jaw opening muscles) using bipolar wire electrodes. The magnitude of the jaw opening reflex at different intensties of electro-acupuncture(1volt 4volt and 10volt) was estimated by averaging the 30 superimposed dEMGs recorded on an oscilloscope and audiomonitor. Data were analysed statistically with ANOV A and paired t-test. The obtained results were as follows: 1. Pain thresholds were increased 7.7 %, 15.4 %, 17.3 % in the teeth and 11.1 %, 19.0 %, 25.4 % in the gingiva as the intensities of electro-acupuncture increased incrementally. 2. Amplitudes of dEMG were decreaed 8.3%, 22.4%, 27.4% in the teeth and 9.8%, 36.5%, 42.2 % in the gingiva as the intensities of electro-acupuncture increased incrementally. 3. Inhibition of pain responses by the electroacupuncture was more effective in the gingiva than in the teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.4
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• pp.718-730
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• 1995

This study was performed to measure the mandibular movement and the changes of masicatory and sternocleidomastoid muscle activity reflected by occlusal disturbance during habitual chewing. For this study, 18 subjects(14 males and 4 females with an average age of 24.0) were selected. The impression of each subject were taken for measuring intermolar distance on lower dentition. The activities of masticatory and sternocleidomastoid muscle and the mandibular movement were recorded and analyzed during habitual chewing by means of E.M.G.(electromyograph), E.G.N.(electrognathograph), rotate program in BioPak analyzing system(BioResearch Inc.). The results were as follows : 1. In EMG of the mandibular rest position, the mean value of muscle activites were increased by nocleidomastoid muscle and anterior belly of digastric muscle(0.05

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.341-355
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• 1999

Squamous cell carcinoma is the most common type of oral cancer and odontogenic myxoma is relatively uncommon benign tumor of mesenchymal origin. There are, to our knowledge, no prior reports of simultaneously occurring squamous cell carcinoma and odontogenic myxoma of the jaw bones. In this case, at first, the plain films and computed tomograms revealed a large expansile multilocular radiolucent lesion on left mandible and marked expansion of cortical plate. In addition this radiograms revealed also infiltrative bony destruction of anterior and medial border of ascending ramus of left mandible and alveolar bone of left maxilla, floating teeth on left lower molar area and metastatic enlargement of left submandibular, jugular digastric and spinal accessory lymphnodes. Magnetic resonance imaging of this patient revealed infiltrative growth of tumor on alveolar bone of left maxilla, left retromolar fat pad. left masseter and left medial pterygoid muscle. Intraoral presurgical biopsy presented typical features of squamous cell carcinoma. After chemotherapy with radiation therapy during 6 months. this central lesion was diagnosed as odontogenic myxoma by the postsurgical biopsy. After 3 months, this patient presented multiple metastatic signs at lumbar spines, rib and liver. Consequently, our case is simultaneous occurrence of squamous cell carcinoma and odontogenic myxoma.

• The Journal of Korean Medicine
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• v.20 no.1 s.37
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• pp.106-112
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• 1999

The purpose of this study is to investigate the effects of Bee Venom Herb-Acupuncture on the jaw opening reflex evoked by tooth pulp stimulation. Rats were anesthetized with thiopental sodium given intraperitoneally in an initial dose of 80mg/kg. Maintenance doses of 5mg/kg thiopental sodium were given through a cannular in the femoral vein as required to maintain light anesthesia. To apply noxious stimuli, a pair of enameled wires were inserted into the tooth pulp of the lower incisor. The effects of conditioning stimuli were estimated as an indicator of the degree of suppression of the digastric muscle electromyogram(dEMG) in the jaw opening reflex. Bee Venom Herb- Acupuncture(0.2% solution 0.1ml/rat) was injected to Hapgok(LI4) loci. In addition, Normal Saline (0.1ml/rat) was injected to Hapgok loci so as to compare the degree of suppression elicited from Bee-Venom. By administration of Bee Venom Herb-Acupuncture, the amplitude of dEMG was maximally suppressed to $67.5{\pm}3.38%$ ipsilaterally, 73.33{\pm}8.00%$ contralaterally. Generally, the dEMG activities caused by electrical stimulation were gradually suppressed during the stimulation and maximal suppressive effect showed at 15min after its onset. However the dEMG activities by Be Venom Herb-Acupuncture were immediately suppressed after its onset and the suppressive effect continued for a long time compared to electrical stimulation. In conclusion, Bee Venom Herb-Acupuncture may have a different mechanism of analgesia from that of electro-acupuncture and contribute to the modulation of pain analgesia.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.6
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• pp.43-49
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• 2004

Electric pulp test is a method to examine the vitality of dental pulp using physical and chemical stimulation. During the pulp test, the current stimulates intradental nerve, and it makes patients painful. In this paper, we measured each activating response EMG in anterior belly of digastric muscle, voice, and finger movement during the pulp test by increasing stimulus intensity gradually. We also measured excessive stimulus time from the activating responses (EMG, voice, and finger movement) to the end of the stimulation. We measured and analyzed excessive stimulus time for each stimulus detecting method. As a result, we developed automatic stimulus breaker using the human responses to stimulus during electric pulp test. We reduced the excessive stimulus time by disconnecting the pulp tester stimulus output rapidly in 10 ms after activating human response.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.103-121
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• 1989

The purpose of this study was to investigate the influence of balancing interference on the activity of masticatory muscles and condylar path. Eight dental students of Won Kwang University without any symptoms of temporomandibular disorder and occlusal interferences, were selected for this study, The balancing interference was provided by construction and cementation of cast metal crowns on the upper and lower first molars. For the measurement of muscle activity, bioelectric processor (EM2, Myotronic Res., Inc., U.S.A.) was used and for the condular path, computerized electronic pantograph (Pantronics, Denar Corp., U.S.A.) was used and the myographic recordings were taken bilaterally from the anterior temporal, masseter and digastric muscles on rest position and on functions. These experimental procedures were done before cementation of experimental crown, three days after cementation of experimental crown, one week after, two weeks after and then one week after removal of experimental crown. The results are as follows: 1. The PRI score was increased at three days after application of balancing interference, and decreased at two weeks after. 2. Three subjects showed mild symptom of temporomandibular disorder at three or four days after application of interference, but the symptom was subsided in one or two weeks after application of interference. 3. One week after application of balancing interference, the activity of ipsilateral anterior temporal muscle in four subjects was decreased on gum chewing at experimental site. 4. Three days after application of balancing interference, the activity of ipsilateral anterior temporal muscle in three subjects was increased on gum chewing at non-experimental site. 5. The influence of balancing interference on the activity of anterior temporal, masseter and gigastric muscle was not prominent.

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.569-586
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• 1994

The purpose of this study is to investigate the effect of loss of incisal function on the thickness, growth activities, ultrastructure of the condylar cartilage and on the muscle fibers of masseter superlicialis, anterior belly of digastric muscle in the growing rats. 37 day-old-rats of which incisors had been trimmed every day received soft diet from weaning and were studied by the autoradiography, electron microscopy and muscle histochemistry. The results obtained were as follows : The thickness of the fibrous, proliferative layer in superior, posterosuperior portion of the condylar cartilage was significantly(p<0.01) reduced in experimental groups and the decrease rate of fibrous layer thickness was greater in posterosuperior portion than in superior portion of cartilage and was greater than in proliferative layer. In normal group, more cells of posterosuperior portion moved more rapidly towards the medullary cavity. In experimental group, the labelling index of posterosuperior portion was decreased in proliferative layer at 2 hours, in transitional layer at 1, 2 days, in hypertrophic layer at 4 days after injection relative to posterosuperior portion of control group. But labelling index of superior portion was not different from that of control group at all time course after injection. From the muscle histochemistry, the diameter of type IIB fibers in masseter superficialis muscle, type IIA, type IIB fibers in anterior belly of digastric muscle decreased significantly(p<0.01) relative to controls in experimental group. From electron microscopic study, in the fibrous layer of the posterosuperior portion of condylar cartilage in normal group, many fibroblast like cells near the joint cavity showed extensive remodelling activities in ultrastructure. There was no morphological changes between experimental and control group in all cartilage cell layers of superior portion but cells near the joint cavity in fibrous layer of posterosuperior portion of experimental group showed morphologically inactive state relative to control group.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.591-598
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• 2000

This study was designed to analysis the airway which affects to breathing, speech and facial growth pattern in unilateral cleft lip and palate patients. Upper airway and the position of hyoid bone pattern were analyzed on the lateral cephalometric radiographs of the 78 subjects of complete unilateral cleft lip and palate group and each group was divided two sub-groups by circumpubertal growth peak and gender. These data were statistically analyzed to examine the difference between pre-circumpubertal growth peak group and post-circumpubertal growth peak one, and between male and female group. The results of this study were as follows: 1. After circumpubertal growth peak stage, the position of hyoid bone was lower than before in both male and female group. 2. After circumpubertal growth peak stage, the measurement were increased in CV3ia-APH, PNS-ad which related to the volume of pharyngeal space. This was due to the decrease of adenoid and anteroiferior growth of mandible and affected to breathing and speech after circumpubertal growth peak. 3. During circumpubertal growth peak stage, all measurements increased more in male than female group, which due to the different amount of growth in different gender. 4. The position of hyoid bone was lower in male than female group in all age group. 5. After circumpubertal growth peak stage, CV3ia-APH increased more in male. This was due to the more growth in madible of male which resulted in the activation of digastric muscle.