• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.213-226
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• 1987

The purpose of this study was to standardize and classify the coordination pattern among the left and right masseter and anterior temporal muscles, in terms of integrated EMG values per stroke during gum chewing in normal subjects. In this study, 20 normal subjects were selected to chew a piece of gum and integrated EMG from middle portion of the masseter and anterior temporal muscles on both sides were recorded 20 times during each of the right and left chewing respectively. And the Bioelectric Processor Model EM2 (Myo-tronies Research, Inc., U.S.A.) with the surface electrodes was used to record the EMG activity during all experimental procedures. The results were as follows; 1. In all subjects, the chewing side masseter muscle was predominantly active among the four muscles examined. 2. The integrated EMG value of the middle of masseter muscle was significantly predominant than those of the anterior temporal muscle (p<0.0001) on the chewing side, but no significant predominant was observed on the nonchewing side (p<0.98). 3. In comparison with same muscles on the chewing and nonchewing side, low correlation coefficient was found between the middle of masseter muscles (R=0.317), but high correlation coefficient was found between the anterior temporal muscles (R=0.738). Between two muscles on the same side, there were significant correlation in the chewing (R=0.557) and nonchewing side (R=0.625). 4. In the coordination patterns among four muscles examined, distinct individual differences were found, but in an identical subject one fixed pattern appeared with significant reproducibility.

• Journal of dental hygiene science
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• v.12 no.1
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• pp.45-53
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• 2012

The purpose of this study is to work out plans to reduce oral malodor by carrying out effective methods. In the research, 17 volunteers were selected from the students at Sahmyook Health University's Dental Hygiene Dept. in order to measure the effects of reduction of oral malodor. The results are as follows. 1. As time passes, both the control group and the experimental group proved the effects of the reduction of oral malodor for 20 minutes after the experiment(p<0.05). 2. The experimental group with tooth-brushing showed a statistically significant difference compared with the control group from a lapse of 5 minutes after the experiment to 20 minutes(p<0.05). 3. The experimental group with tongue cleaner did not prove a statistically significant difference compared with the experimental group with toothbrushing( p>0.05). 4. The experimental group in which participants took a candy showed a statistically significant difference compared with the control group after 5 minutes(p<0.05). 5. The experimental group with chewing a gum proved a statistically significant difference compared with the control group for 10 minutes(p<0.05). Using a washing implement of the tongue, taking a candy, and chewing a gum proved the same effect of reducing foul breath as in the case of operating a tooth-brushing. This experiment proves that taking a candy or extending time of chewing a gum was effective in a short time, and using a tongue cleaner or chewing a gum for 5 minutes was a useful method for reducing oral malodor if not operating a tooth-brushing.

• Journal of Korean society of Dental Hygiene
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• v.11 no.6
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• pp.853-862
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• 2011

Objectives : The aim of this study was to investigate the number of self-report symptoms for temporomandibular disorders(TMD) and related factors in the third grade students of high school. Methods : A total of 1,043 high school the 3rd students age 16 20 completed a questionnaire from 11 high schools in Andong city from April to June 2010. Student's t-test was used to analyze the difference of TMD number. Multiple regression analysis was performed to determine the effects of independent variables on TMD number. Results : 1. Students who have one TMD were 71.3%, two 41.7% and over three 25.7%, respectively. 2. The number of TMD symptom of students who have no good habits such as clenching, bite lip and cheeks, resting on hand, chewing gum, hard foods, and unilateral chewing was a statistically significant higher than those who doesn't have ones(p=0.00). 3. TMD number of students who have been under more stress was a significantly higher than those who didn't have been(p=0.00). 4. Bite lip and cheek(${\beta}$=0.03, p=0.037), chewing gum(${\beta}$=0.03, p=0.029), resting on hand(${\beta}$=0.04, p=0.006), hard foods(${\beta}$=0.07, p=0.000), and stress out(${\beta}$=-0.03, p=0.018) were significantly associated with TMD number by multiple regression analysis. Conclusions : Variables associated with TMD were bite lip and cheek, chewing gum, resting on hand, hard foods, and stress out factor. According to our findings, it is so important to teach good habits on oral health to the 3rd grade students in high school. Further prospective study should explore cause of TDM from those variables.

• 대한치과보철학회:학술대회논문집
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• 1999.04a
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• pp.33-33
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• 1999

• The Journal of the Korean dental association
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• v.48 no.6
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• pp.436-442
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• 2010

Objective: Transmission of S. mutans, a major dental caries pathogen, occurs mainly during the first 2.5 years of age. Children appear to acquire S. mutans mostly from their mothers, but few studies have investigated preventive effect of xylitol to S. mutans transmission from mother to child. The aim of this study was to perform a follow-up evaluation the preventive effect of xylitol chewing gum of the S. mutans of children's oral cavities, which included the characteristics of vertical transmission from mother to child. Methods: The mothers voluntarily participating in a women's oral health prevention program were divided into two groups (a control and a xylitol group). The subjects were 20 mother-child pairs, who were monitored for 30 months. Xylitol chewing gum group had consumed 2 gum pellets, 3 times a day for 24 months, and then they were followed until 30 months. At baseline, 24 and 30 months whole stimulated saliva samples were collected from the mothers. Children were also recruited from 6 months to 30 months after birth and were collected their dental plaque samples. After isolation and identification, the analysis of the colony count, transmission electron microscopy and real-time RT-PCR were performed to analyze the characteristics of S. mutans. Results: The S. mutans counts decreased steadily in the xylitol group at 24 months, but increased at 30 months. The similar results were showed at their children. While the glucan synthesis was decreased at xylitol group both mother and child. The expression of gtfB, gtfD and ftf were significantly reduced in the xylitol group both mother and child (p<0.05). Conclusions: These findings indicate that chewing xylitol gum over a long period may decrease the expression of the genes associated virulence and reduced the glucan synthesis of S. mutans, which can result the preventing the mother-to-child transmission of S. mutans.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.1
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• pp.53-71
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• 1991

This study was performed to investigate the muscular activity of the complete denture wearers compare with subjects with natural teeth. For the study, 10 subjects with natural dentition and 18 upper and lower complete denture wearers selected and the Bio-electric Processor EM2(Myo-tronics Reaserch, Inc., U.S.A.) with the surface electrodes was used to record electromyographic activity from the right and left middle of masseter and anterior temporal muscles of each subject during mandibular postural rest position, tapping of teeth from postural rest position, maximal clench, and right and left gum and raw carrow chewing. This results of this study were as follows : 1. In mandibular postural rest position, the denture wearers produces high muscular activity in contrast to natural objects(P<0.05) but, there was no difference between the state of denture removal and insertion, and the muscle activity of the anterior temporal muscle was high than the middle of masseter muscle in natural objects and denture wearers. 2. In tapping of teeth, there was no difference in muscle activity between natural objects and the state of denture removal of denture wearers. 3. In maximal clench, there was markedly lower denture wearers than natural objects in muscle activity, and the ratio of mean voltages was about 36 percentages. 4. In gum and raw carrow chewing, the activity was lower than natural object, the ratio was about 59 percentages. 5. In chewing, the mean voltages of the middle of masster muscle on the chewing side was highest, followed by the anterior temporal on the chewing side, the anterior temporal and masster muscles on the non-chewing side.

• Journal of Oral Medicine and Pain
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• v.32 no.3
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• pp.319-328
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• 2007

The purpose of this study was to quantitatively assess treatment effect of physical therapy on experimentally-induced masseter muscle fatigue by two parameters of muscle stiffness and elasticity. Three physical therapeutic modalities inducing electroacupunture stimulation therapy(EAST), Microwave diathermy and low-level laser therapy(LLLT) were compared. 10 healthy volunteers with normal occlusion (mean age of $26.3{\pm}1.16$ years, M:F=1:1) were participated in this study. All subjects were asked to chew gum on the right side until they felt pain(more and VAS 5 (0 to 10)) and their masseter muscles were examined with a tactile sensor in order to evaluate changes of stiffness and elasticity according to gum chewing and three physical therapeutic modalities. Subjective discomfort or pain was self-estimated by VAS as well. Unilateral gum chewing increased stiffness and decreased elasticity only on the chewing side but VAS increased on the both sides(p<0.05). EAST or Microwave diathermy greatly decreased stiffness and VAS and increased elasticity(p<0.05) but LLLT did not exhibit significant difference. From the results of this study, it is concluded that both EAST and Microwave diathermy have favorable effect on stiffness and elasticity of muscles and pain relief while effect of LLLT is not reliable. In addition, experimental unilateral gum chewing compromises stiffness and elasticity of masseter muscles only the chewing side while subjective discomfort or pain can be felt on the both sides.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.6
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• pp.577-589
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• 2002

There are several variations in normal mastication. In them, unilateral mastication is chewing, predominantly on a preferred side of the dentition and hardly on e non-preferred side. Continual unilateral mastication may alter the coordination of masticatory muscles. Although they studied about these EMG of masticatory muscles, there were no information about characteristics of masticatory muscle activity in unilateral mastication. Therefore, In this study, we investigated the activity of the masseter and anterior temporal muscles during rest, clenching in maximum intercuspation and gum chewing in habitually unilateral mastication group compared with normal group and tried to know effects of continual unilateral mastication on activity of masticatory muscles. The results of this study were as follows 1. In electromyographic activity during rest, in bilateral mastication group pattern of muscle activity of right and left side was symmetrical. But, in unilateral mastication group, records of anterior part of temporal muscle was higher than that of bilateral mastication group (p<.01) and patterns of muscle activity of right and left side in both muscle were asymmetrical.(p<.05) 2. In electromyographic activity during clenching in maximum intercuspation, records of superficial part of masseter muscle were higher than anterior part of temporal muscle in both group. Muscle activity of temporal muscle in unilateral mastication group was a little higher han bilateral mastication group and asymmetry of activity pattern in temporal and masseter muscle was shown but these differences were not statistically significant. (p<.05) 3. In electromyographic activity during gum chewing, temporal muscle was activated earlier than masseter muscle and maximum bite force is derived from masseter muscle in both group. In unilateral mastication group, electromyographic activity of masseter and temporal muscle of preferred chewing side, regardless of right or left side chewing, was higher than that of bilateral mastication group and especially, difference in masseter muscle was statistically significant. (p<.01) Based on the above results, our study suggested that recording of masticatory muscle activity will be helpful in the effective diagnosis and treatment of some types of the parafunctional habits.

• 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.

• 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.