• The Journal of Korean Academy of Prosthodontics
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• v.32 no.1
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• pp.103-119
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• 1994

The purpose of this study was to evaluate the mandibular movements of TMD patients comparing to normal persons. Sirognathograph was used to measure five parameters of mandibular movements of twenty normal persons and eight TMD patients. Five parameters were (1) Maximum opening during maximum opening and closing, (2) Mean velocity during maximum opening and closing, (3) Maximum opening during unilateral chewing, (4) Mean velocity during unilateral chewing, (5) Consistency of mandibular movement during unilateral chewing. Based on above results, new Mandibular Movement Index(M.M.I.) was formulated and compared to Helkimo's Clinical Dysfunction Index by measuring two indices before treatment and 2 weeks, 4 weeks, 6 weeks, 8 weeks after treatment. The conclusions were as follows: 1, The amounts of maximum opening and mean velocity during maximum opening and closing of TMD patients were less than those of normal persons(p<0.01). 2. The amounts of maximum opening and mean velocity during unilateral chewing of TMD patients were less than those of normal persons(p<0.05) (P<0.01). 3. Although TMD patients showed limited mandibular movements during unilateral chewing, the consistency of mandibular movements was better than that of normal persons(p<0.05). 4. Both mandibular movement index and Helkimo's Clinical Dysfunction Index, were useful in diagnosing TMD patients.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.3
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• pp.427-452
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• 1998

To elucidate the effects of food texture such as hardness, cohesiveness, adhesiveness on mastication procedure, the electromyographic activity (EMG) of the masticatory muscles and the chewing movements were analyzed in eighteen young subjects during ordinary chewing. Seven different foods were selected by sensory texture profiling and mechanical test with texturometer; egg white, sausage, pizza cheese, yang-geng, biscuit, peanut and almond. The indexes of jaw movements used were the chewing number, chewing time, maximum opening, average opening, closing velocity and opening velocity. The EMG indexes analyzed were maximum and average integrated amplitude of the anterior temporal and masseter muscles. The results obtained were as follows. 1. The chewing time and chewing number, mandibular displacement and mandibular movement velocity were not changed by the hardness, cohesiveness and adhesiveness of the food (p>0.05). 2. The harder food materials showed a higher amplitude of the anterior temporal muscle integrated EMGs than the softer ones (p<0.05). 3. The maximum and average integrated EMGs of the masseter muscle increased with the increase of hardness of the food (p<0.05). 4. The integrated EMGs of preferred side and non-preferred side masticatory muscles increased with the increase of hardness of the food (p<0.05). 5. The adhesiveness and cohesiveness of the food were not the determining factor to the integrated EMGs of masticatory muscles (p<0.05).

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.295-307
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• 1997

This study was performed to investigate the reproductibility of eccentric mandibular movements according to preferred chewing side, range of mouth opening, type of lateral guidance and involvement of temporomandibular disorders. 50 patients with temporomandibular disorders and 65 dental students without any signs and symptoms were randomly selected for this study as the patients group and the control group, respectively. For recording and observation of eccentric mandibular movement trajectory, BioEGN$^\textregistered$ of Biopak$^\textregistered$ system (Bioresearch Inc., USA) was used. Each eccentric movement to anterior, right and left side was performed three times similar to the movement pattern for Pantronic Reproducibility Index. mandibular path was analyzed by three dimensional positional change and the three paths from one direction were compared with one another. From this, reproducibility index of one-directional lateral movement could be calculated, and total reproducibility index, named BioEGN reproducibility index(BERI), was also computed from three-directional eccentric movement likewise. BioEGN reproducibility Index could have four value of score by small or large scale, and by outgoing or incoming movement. The data were analyzed by SAS/stat program and the results obtained were as follows: 1. Right side chewing subjects showed more consistent pattern In reproducibility index in comparison between patients group and control group than left chewing subjects have done, and reproducibility was low in patients group. However, there was no difference between the two stoups in bilateral chewing subjects. 2. There were no difference in reproducibility index between preferred chewing side and contralateral side in unilateral chewing subjects whereas reproducibility index in left side on outgoing movement were higher than in right side in bilateral chewing subjects. 3. Difference in total reproducibility index(BERI) between canine guidance group and non-canine guidance group were not observed though difference in reproducibility index on lateral movement were observed in part. 4. There were no difference in reproducibility index between affected side and contralateral side in unilaterally affected patients, and between unilaterally affected patients and bilaterally affected patients in patients group. 5. Highly significant positive correlationship were shown among the four 쇼pes of total reproducibility index(BERI) in total subjects, and range of clinical mouth opening was negatively correlated with BEBI on outgoing movements and with index on outgoing movement to preferred side.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.181-193
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• 1987

Author examined the chewing patterns between the 16 normal subjects and the 10 complete denture wearers with LED mandibular tracking device, and analized the chewing envelope and opening, closing velocity during chewing various test foods-standardized carrot, ham and almond. The results were as follows; 1. The chewing envelope of carrot chewing was greater than that of ham chewing in both groups. 2. The average opening velocity was faster than the average closing velocity in both groups. 3. During chewing carrot or almond, the chewing envelope of dentate stoup was greater than that of denture group, but during chewing ham, there was no statistical difference. 4. During chewing carrot or almond the average opening and closing velocity in dentate group were faster than those of denture group.

• Journal of Oral Medicine and Pain
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• v.22 no.2
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• pp.207-217
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• 1997

This study was performed for Investigation of the magnitude of mandibular positional change in maximum mouth opening. protrusion, lateral excursion, gum and peanut chewing with BioPAK system(Bioresearch Inc. USA) which can analyze mandibular rotational torque movements. For this study 17 female patients with Temporomandibular joint(TMJ) closed lock and 18 female control without any Temporomandibular disorders(TMDs) signs and premature occlusal contact were included. The obtained results were as follows : 1. In maximum mouth opening, the mandibular rotational angle and distance of patients were significantly greater than those of control group in horizontal plane(P<0.05). 2. In protrusion, the mandibular rotational angle and distance of patients were significantly greater than those of control group in frontal and horizontal plane(P<0.01, P<0.05). 3. The mandibular rotational angle and 야stance in lateral excursion to affected side of patients were significantly greater than those in lateral excursion to non-affected side in frontal plane(P<0.05). 4. The mandibular rotational angle in gum chewing to affected side of patients was significantly greater than that in gum chewing to non-affected side in frontal plane. 5. The mandibular rotational angle and distance in peanut chewing to affected side of patients were significantly greater than those in peanut chewing to non-affected side in frontal and horizontal plane. 6. The mandibular rotational angle and distance in peanut chewing to affected side of patients were greater than those in gum chewing, and was the same result in control group in frontal and horizontal plane.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.4
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• pp.533-548
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• 1998

The purpose of this study was to investigate the influence of balancing interference on the mandibular movement and masticatory muscle activity. 5 subjects(male. average age of 24.3) without dysfuction in masticatory system were selected. The balancing interference was provided by construction of cast metal crown and onlay on the upper and lower first molars. Clinical examination, changes displacement and velocity, and muscle activity were recorded and analyzed by means of BioPak system(Bioresearch Inc., Milwaukee Wisconsin. USA). The results were as follows ; 1. In clinical examination, various symptoms were reported by all subjects after application of interference. Almost symptoms were subsided after elimination of interference. 2. In the border movements in frontal plane, lateral border movement toward non-interference side was changed according to the interference after application of interference. Immediately after removal of interference, border movements' pattern was recovered as same as before experiment. 3. During gum chewing on the non-interference side, horizontal movement was decreased immediately after application of interference(p<0.05). 1 week after application of interference, horizontal movement was more decreased in 3 subjects and showed a chopping type masticatory stroke. But in 2subjects, horizontal movement was increased to avoid interference. 4. In EMG of the mandibular rest position, no significant changes were showed in the experiment period(p>0.05). 5. During gum chewing on the interference side, the activity of opposite temporal muscle was increased immediately after application of interference(p<0.05). 1 week after application of interference. The activity of ipsilateral temporal muscle and left and right masseter muscles was increased (p<0.05). 1 week after elimination of interference, increased muscle activity was recovered about the same level as before experiment. 6. During gum chewing on the non-interference side, 1 week after application of interference, the activity of ipsilateral temporal muscle was increased (p<0.05). 1 week after elimination of interference. increased muscle activity was returned about the same level as before experiment.

• Journal of Oral Medicine and Pain
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• v.23 no.2
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• pp.143-155
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• 1998

This study was performed to investigate the factor that might affect mandibualr body rotation. For the study, 115 patients with temporomandibular disorders and 35 dental students without angy signs and symptoms of temporomandibular disorders were randomly selected as the patient group and the contreol group, respectively. Preferred chewing side, Angle' classification, lateral guidance pattern, and affected side were clinically recorded, and the amount of Mandibular body rotational torque movement was measured in wide opening and closure, in right and left excursion with vertical and lateral distance in frontal plane, right and left rotational angel in horizontal and in frontal plane. Masticatory muscle activity of anteriorocclusal contact pattern on maximal hard biting were also observed synchronously with BioEMG and T-Scan , respectively. The observed items were muscle activity of anterior temporalis and superficial masseter, and tooth contact status related to contact number, force, duration, and occlusal unbalance between right and left arch. The data collected were analyzed by SAS statistical program. The results of this study were as follows : 1. Mean value of vertical distance in frontal plane in wide opening and closure was more in control subjects than in patients, but there was no difference for rotational angle. In right excursion, rotational angles were greater in patient group than in control group. 2. Comparison among the subjects by preferred chewing side did not reveal any significant difference, but comparison among patients by affected side showed more rotational amount in bilaterally affected patients than in unilaterally affected patients. 3. Comparison among the subjects by Angle's classification or lateral guidance pattern revealed no difference. There was also no difference between preferred chewing side and contralateral side, and between affected side and contralateral side. 4. Positive correlation in madibular rotational torque movements were observed among vertical distance, total horizontal rotation angle, electromyographic activity of anterior temporalis, tooth contact number, and tooth contact force but total frontal rotation angle almost did not show any correlation with other variables except vertical distance.

• Journal of the korean academy of Pediatric Dentistry
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• v.1 no.1
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• pp.49-55
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• 1974

Electromyographic studies were performed on the action of the masseter muscles. Among the children aged from 6 to 8 years, ten children with normal occlusion and another ten with space maintainer were selected. The children were divided into 3 groups. They were: 1) A group: Children who removed space maintainer 2) B group: Children who inserted space maintainer 3) C group: Children with normal occlusion. The electromyogram was recorded with 4 channel polygraph. (Grass model VII) Electrodes which were cup-typed gold disks, 9 millimeters in the diameter, were located on the superficial layer of masseter muscles. The electromyogram was recorded in the physiologic rest position, molar occlusion, chewing movement, protraction, left lateral movement, and right lateral movement. The conclusions were as follows. 1. In the physiologic rest position, lateral movement, the electrical potentials of the masseter muscles were not changed clearly in each groups. 2. In molar occlusion, chewing movement, The electrical potentials of the masseter muscles of the B group were almost 10% higher than those of A group, and were almost 60-70% in comparision with C group. 3. In protraction, the electrical potentials of the masseter muscles of the B group were almost 40% higher than those of A group, and were almost equal to C group. 4. The electrical activities of the masseter muscles in the mandibular movements were in the following order: (1) Molar occlusion (2) Chewing movement (3) Protraction (4) Lateral movement.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.15-29
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• 1997

The author performed this study to investige the relationship between condylar movements recorded with Pantronic and mandibular movements at incisal area recorded with BioEGN. For this study 24 patients with Temporomandibular disorders(TMDs) and 30 dental students without any masticatory symptoms were selected as patients group and control group, respectively. The items recorded with Pantronic(Denar Corp., USA) were immediate side-shift, orbiting path, protrusive path, and PRI. BioEGN(Bioelectric-gnathography, Bioresearch Inc., USA) were sued to measure the amount of mandibular torque movement in frontal and horizontal plane and also the distance of mandibular translation at incisal area. Amount of mandibular rotational torque movement was analyzed by angle and difference between both condyles in frontal and horizontal plane. The collected data were processed with SAS program and conclusion were as follows : 1. Mean value of items recorded with Pantronic were not significantly differed between patients group and control group except the item of pantographic reproducibility index(PRI). The value of PRI was 39.5 in patients group, and 29.5 in control group. 2. The amount of mandibular torque movement was not differed tin early protrusive and early left excursion between patients group and control group, but in early right excursion, patients group showed more value than control group did. 3. The distance on sagittal plane in early eccentric movements were longer in patients group than those in control group, but the distance of maximal eccentric movements were not significantly differed between patients group and control group. 4. Items which showed significant correlation with PRI were progressive side-shift, and horizontal torque movement in early protrusion and right excursion. 5. The angle of protrusive path of affected side was greater than of non-affected side in unilaterally affected patients, but the protrusive angle of preferred chewing side was not differed from that of contralateral side in control group. 6. The amount of torque movement in early protrusion and right excursion were greater in patients with coincidence of affected side and preferred chewing side than in patients without coincidence.

• Journal of Oral Medicine and Pain
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• v.46 no.4
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• pp.155-160
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• 2021

The masticatory muscle disorder is the most common problem that patients with temporomandibular disorder often complain. For such complaints, treatment is directed towards reducing hyperactivity of muscles or effects of the central nervous system. However, if nonspecific occlusal change or pain persists, it is necessary to consider that muscle weakness might be the cause of the persistence of temporomandibular disorder. Stabilization of occlusion and improvement of the pain symptoms were achieved in both cases through the chewing gum exercise. This exercise may enable masticatory movements done in normal function by using muscle engram and achieve reinforcement of the masticatory muscles with balanced, simultaneous contacts of the teeth. In addition, it may be a viable method for treating temporomandibular disorders that do not respond well to conventional mandibular stabilization therapies.