• 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.

• Journal of Oral Medicine and Pain
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• v.24 no.4
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• pp.421-437
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• 1999

This study was performed to investigate the electromyographic(EMG) activity, firing time and sequence of the mandibular elevator muscle on gum chewing. For this study, 28 patients with temporomandibular disorders(TMD), especially internal derangement of TM joint, and 16 dental students without any signs and symptoms in the masticatory system were selected as the patients group and as the normal group, respectively. The patients group was composed of 14 right and 14 left side affected patients. For recording of EMG activity(${\mu}V$) of the anterior temporalis(TA) and the masseter muscle(MM), and measuring of firing time(millisecond) from the start of mandibular opening movement to the firing of the muscles, BioEMG, BioEGN, and Combo program integrated in the Biopak system(Bioresearch Inc., Milwaukee, USA) were used. Gum chewing stroke was performed in both right and left side for several times, and the first and the second chewing strokes were analysed and compared with regard to EMG activity, firing time, firing sequence, correlation between EMG activity and firing time. The data obtained were analysed by SPSS windows program and the results of this study were as follows : 1. In the patients group, chewing on the affected side showed higher EMG activities in the masseter of the side than those of the contralateral side, but chewing on the unaffected side showed higher EMG activity in the masseter and in the anterior temporalis of the side than those of the contralateral side. 2. There were no difference of firing time between both sides on chewing on the affected side, but firing time in the chewing side were earlier than that of contralateral side on chewing on the unaffected side in patients group. 3. In the normal group, EMG activities in the masseter and in the anterior temporalis in the chewing side were always higher than those of the contralateral side, and there were no difference of firing time between the two sides. 4. In general, firing sequence of four muscles of both sides were ipsilateral TA, ipsilateral MM, contralateral TA, and contralateral MM in earlier order of time in both groups. Correlation coefficients between EMG activity and firing time were negative value, and more significant correlation were appeared in the normal group than in the patients group.

• The korean journal of orthodontics
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• v.48 no.2
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• pp.90-97
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• 2018

Objective: The aim of this study was to assess the analgesic effect of a single application of low-level laser therapy (LLLT) on spontaneous pain and pain on chewing after placement of initial archwires. Methods: Forty-two patients (26 women, 16 men) were randomly recruited for this split-mouth randomized clinical trial. Each patient received super-elastic nickel-titanium (NiTi) initial archwires (0.012, 0.014, 0.016, and 0.018-inch [in]) in the maxilla for leveling and alignment for an interval of 4 weeks between archwires. One side of the mouth was randomly designated as experimental, while the other side served as placebo. After insertion of each archwire, the experimental side was irradiated with a diode laser for 3 seconds each on 5 points facially and palatally per tooth, from the central incisor to first molar. On the placebo side, the laser device was held the same way but without laser application. A numerical rating scale was used to assess the intensity of spontaneous and masticatory pain for the following 7 days. The Mann-Whitney U test was used to compare pain scores between sides. Results: Patients in the LLLT group exhibited significantly lower mean scores for spontaneous pain after insertion of the initial two archwires (0.012-in and 0.014-in NiTi; p < 0.05), while there was no significant difference for 0.016-in and 0.018-in wires between the LLLT and placebo groups. LLLT significantly reduced chewing pain scores (p < 0.05) for all archwires. Conclusions: A single dose of LLLT considerably lessened postoperative pain accompanying the placement of super-elastic NiTi wires for initial alignment and leveling.

• Journal of Oral Medicine and Pain
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• v.21 no.2
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• pp.369-382
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• 1996

The author performed this study to investige the relationship between condylar movements recorded with Pantronicⓡ and mandibular rotational torque movements with BioEGNⓡ. For this study 56 patients with Temporomandibular disorders(TMD) and 30 dental students without any masticatory signs and symptoms were selected as patients group and control group, respectively. The items recorded with Pantronicⓡ(Denar Corp., USA) were immediate side-shift, progressive side-shift, angle of orbiting path, protrusive path and PRI. BioEGNⓡ(Bioelectric gnathography, Bioresearch Inc., USA) were used to measure the amounts of mandibular rotational torque movements in frontal and horizontal plane, and the distance of mandibular translation at incisal area. Amount of mandibular rotational torque movement depicted between the condyles was automatically analysed by angle and difference in frontal and horizontal plane. The obtained data were processed with SAS program and the conclusion of this study were as follows : 1. Mean values of items between patients group and control group in Pantronic measurements were not significantly different except in left protrusive path and in Pantronic Reproducibility Index(PRI). There were no significant difference of condylar paths by preferred chewing side and affected side between the two groups. 2. The amount of mandibular rotational torque movements were differed in frontal angle and difference on protrusion, and in frontal and in horizontal difference on left excursion between the two groups. But the amounts of translatory movements were actually same on all eccentric movements. 3. The amount of mandibular rotational torque movements with splint mere almost not changed from those without splint, with the exception of in horizontal measurements on protrusion. 4. The correlations of items between in Pantronic measurements and in BioEGN measurements wert not consistently, significant, however, generally the ISS related significantly with horizontal torque movement positively, and with frontal torque movement negatively on the contrary, the PSS showed positive correlation with frontal torque movement, and negative correlation with horizontal torque movement.

• 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.44 no.3
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• pp.143-153
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• 2014

An 8-years old boy with facial asymmetry and unilateral posterior crossbite on the left side received orthopedic and orthodontic treatment. During the first phase of treatment, the narrow maxillary arch was expanded using an acrylic plate. Then, the acrylic plate was used as a bite block with occlusal indentations from the construction bite that was obtained with the incisors in a coincident dental midline. After the position of the mandible was stabilized, the second phase of orthodontic treatment was initiated using fixed appliances for detailing of the occlusion. Skeletal symmetry, ideal occlusion, and coincident dental midlines were thus achieved. Functionally, occlusal force balance and masticatory muscle activity were improved, and the chewing patterns were normalized.

• The Journal of the Korean dental association
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• v.22 no.4 s.179
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• pp.333-338
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• 1984

This is to report a case of traumatic bone cyst which occurred in the left condylar head of the mandible. It is a very rare case and the prognosis after operation seems to be fair, therefore we report as follows. 1. The pt, a 49 year-old female, has been suffering from difficulties of mastication with disfiguration of face due to deviation of mandible to the right side for 20 years. 2. Histopathologic findings showed the figure of multilocular bony cysts contained with fibrous tissue, osteoid tissue and many hematopoietic cells 3. Roentgenographic features showed well circumscribed radiolucent lesion with some radiopaque area. 4. After clinical evaluation, condylectomy was done to remove the lesion. 5. After the operation, the esthetic problem and masticatory functions were improved.

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.83-92
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• 1989

The pharyngeal teeth and the masticatory process of the basioccipital bone were compared in ten species of Korean bitterlings. Three species, Acheilognathus lanceolata, A. limbatus, A. signifier and Rhodeus ocellatus, which are characterized by the absence of serrations on the side of the pharyngeal teeth, are found to, have reduced occlusal grooves on the outside of occlusal margin, Among Korean bitterlings, differences are found in the developmental degrees of the anterior part of the masticatory process, the grooves on the occlusal surface and the chewing area on the pharyngeal first tooth. The occlusal grooves in herbivorous species are considered to be more developed than those in omnivorous species. Considering these findings, the combination of developmental degrees in the three pharyngeal elements suggests generally the phylogenetic relationships among the Korean bitterlings.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.189-200
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• 1989

The purpose of this study was to investigate the muscle activity of the group function occlusion and the changed canine guided occlusion using EM2. In this study, 13 subjects with group function occlusion and without temporomandibular disorders were selected, each subject was changed to the canine guided occlusion by forming the lingual ramps in the upper canines with light curing composite resin. The muscle activities of the anterior temporal and masseter muscle were recorded in the group function occlusion and immediately, one week, and two weeks after changing to the canine guided occlusion under the condition of maximum voluntary clenching in centric occlusion, lateral excursion, and during gum chewing. The results were as follows: 1. In case of maximum voluntary clenching in centric occlusion, the muscle activities of the anterior temporal and masseter muscle of working and balancing side didn't show any difference immediately after changing to the canine guided occlusion, one week after changing to the canine guided occlusion, one week after changing to it the muscle activities of the anterior temporal masseter muscle of working and balancing side were increased significantly, and two weeks after changing to it the muscle activities of the masseter muscle were increased significantly in comparison with the group function occlusion. 2. In case of maximum voluntary clenching in lateral excursion, the muscle activities of the anterior temporal and masseter muscle of working and balancing side were reduced significantly immediately after changing to the canine guided occlusion, one week after changing to it the muscle activities of the anterior temporal muscle of balancing side and of the anterior temporal and masseter muscle of working side were reduced significantly, and 2 weeks after changing to it the muscle activities of the anterior temporal and masseter muscle of working side were reduced significantly in comparison with the .group function occlusion. 3. During gum chewing, the muscle activities of the anterior temporal and masseter muscle of working and balancing side didn't show any difference immediately after changing to the canine guided occlusion, one week after changing to it the muscle activities of the masseter muscle of working and balancing side were increased significantly, and two weeks after changing to it only the muscle activities of masseter muscle of working side were increased significantly.

• 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.