• Biomedical Science Letters
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• v.24 no.4
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• pp.372-379
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• 2018

Korean society is experiencing rapid growth due to industrialization and urbanization, and the aging of population is emerging. Degradation of the masticatory muscle due to aging and reduction of the number of mastications causes dry mouth syndrome with decreased saliva in the elderly. Changes in the amount and composition of saliva cause various oral diseases, especially, periodontal disease is closely related to the microorganisms that form the plaque. In the elderly education, stimulation saliva was collected at the first visit and the last visit to observe changes in microorganisms in the oral cavity. For the collection of the probes, the paraffin wax was chewed for 5 minutes. The samples were immediately refrigerated in a 50 cc plastic tube and then stored at $-20^{\circ}C$ until the next use. The subjects of this study were the elderly people aged 65 years or older, and the study was conducted on 16 persons, 3 males and 13 females. The distribution of saliva microorganisms according to rolling brushing method showed significant difference in all three groups (Aa & Red complex, Orange complex and Green complex) before and after the education. In the group who answered that they had dentures, it was confirmed that the amount of microorganisms before and after education was significantly reduced in all three groups. There was a significant decrease in the amount of microorganisms in the Aa & Red complex and Orange complex group in the case of hypertension related to systemic disease. In conclusion, the higher the interest of oral health and general health of the subjects, the more effective the education.

• Journal of dental hygiene science
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• v.21 no.1
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• pp.8-18
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• 2021

The purpose of this study is to provide the general history of fostering dentists in Japan and introducing their new roles. This research was conducted based on the government policy report on dentists and the information published by each educational institution. Based on the collected data, the official websites were used to represent the latest statistics of the institutions. The number of dentists in Japan has increased. The government established the National Examination for Dentists to guarantee the quality of dentists. After the standards for developing questions for the national examination were established in 1985, the contents of the examination have been appropriately improved by revising the standards every four years. This improvement has required dental students to study a variety of subjects for six years at dental school. Since dentists in Japan are required to respond to various demands from the nation; the Model Core Curriculum for Dental Education was developed to teach medical ethics and abilities to ensure that dentists conduct themselves professionally. Recently, the roles of dentists have been changing in Japan. When providing dental services to older patients over the age of 65, dentists and other dental professions focus on maintaining oral functions, such as saliva secretion, bite force, tongue movement, and masticatory/swallowing functions. However, oral function-related services for children are different. In addition to providing essential dental services, dental practitioners also provide special treatment, such as oral muscle training, myofunctional therapy, health guidance, and space retainers to the child patients with developmental insufficiency in oral functions. Dentistry in Japan has undergone numerous changes over the years and has continued to offer high-quality dental health services. Thus, information gained from the Japanese experience may be helpful to dental professions in other developed countries for planning oral health measures.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.185-196
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• 2024

Temporomandibular joint disorders (TMDs) can occur at any age, including childhood and adolescence, and pain-related TMDs can affect growth and quality of life. In the present study, recent trends in the diagnosis and treatment of TMDs in children and adolescents were analyzed over a 10-year period. Using 10 years of data from the Health Insurance Review and Assessment Service (HIRA) and Jeonbuk National University (JBNU) Dental Hospital, patients between 0 and 19 years of age diagnosed with K07.6 (temporomandibular joint disorders) were analyzed by 5-year bins. Both datasets indicated a higher prevalence in females (1.2-fold in HIRA, 1.5-fold in JBNU) and in ages 15 to 19 years (72.1% in HIRA, 74.7% in JBNU). HIRA reported a 42.3% increase in prevalence per 100,000 people, from 651.4 in 2011 to 927.0 in 2020. JBNU reported K07.66 (masticatory muscle disorders) as the most common diagnosis in subjects under 10 years of age and K07.60 (internal derangement of temporomandibular joint) in those over 10 years of age. In addition, both were treated mainly by a combination of physical therapy and medication, and the treatment rate increased in accordance with age. Because TMDs can affect various structures in the orofacial region and cause pain that tends to differ with age, an early and specific diagnosis appropriate for age is important for treatment. Therefore, pediatric dentists need to promptly recognize TMDs in children and adolescents and consult with specialists as the prevalence increases.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.303-310
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• 2019

The purpose of this study was to compare the oralmyofunctions (occlusal force, tongue pressure, lip force) of adults and elderly people. And analyzed the factors affecting oral health related quality of life and dysphagia. The study was conducted on 73(over 20 years of age) Residing in Daejeon and Nonsan From December 2017 to May 2018. The data was analyzed using one-way ANOVA, pearson's correlation and multiple regression. The masticatory strength of each age group evaluated the right and left posterior occlusal forces. the elderys group (8.93, 10.80) were lower than adults group(12.51, 14.61) and middle age group(11.63, 14.75)(p>0.05). The tongue pressure was statistically significant lower in eldery group(37.43) than the adult group(60.55), middle-aged group(50.61) (p=0.000). In addition lip force was significantly lower in eldery group(8.57) than adult(12.01), middle-aged(11.37)(p= 0.000). The tongue pressure was positively correlated with the number of natural teeth(r=.566, p<.05), and the lip force (r=.497, p<.05). The quality of life quality related to oral health and dysphagia was tongue strength(p<0.05). It is necessary to recognize the risk of declining oral muscle function caused by aging. especially tongue strength is associated with quality of life and dysphagia. In order to improve the quality of life related to oral health in the aged society, the necessity of regular oral administration and oral muscle training was proposed.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.327-335
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• 2006

Generally, Tension-Type Headache(TTH) patients exhibit muscle pain, but can also have TMJ pain, which includes mouth opening limitation or joint sounds. The purpose of our study is to observe the clinical pain characteristics between TTH patients with muscle pain and TMJ pain. One hundred sixty-seven patients were diagnosed with TTH according to the questionnaires based on the International Headache Society's proposal on the diagnostic criteria of TTH. The patients were classified into three group; arthralgia group (18 patients), myalgia group (50 patients) and arthromyalgia group (99 patients). TTH patients with pericranial muscle pain were classified in the myalgia group. TTH patients with temporal region pain were classified in the arthralgia group. TTH patients with both types of pain were classified in the arthromyalgia group. The parameters in the diagnostic criteria such as quality, intensity, laterality of pain, and aggravation due to physical activities were compared among the three groups. 1. There were no significant differences in the quality of pain among the three groups. 2. There were no significant differences in the intensity of pain among the three groups. 3. There were no significant differences in the laterality of pain among the three groups. 4. A higher percentage of patients in the arthromyalgia group experienced headaches that were aggravated due to physical activity (p=0.03) compared to the other groups. The results of this study show that TTH patients with both arthralgia (TMJ pain) and myalgia (pericranial muscle pain) are more aggravated by physical activity than TTH patients with either one.

• Journal of Oral Medicine and Pain
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• v.36 no.3
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• pp.187-197
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• 2011

Temporomandibular disorders(TMD) is a collective term which is embracing a number of clinical problems that involve the masticatory musculature, the TMJ and associated structures, or both. Myofascial pain, which is a kind of masticatory muscle disorder of TMD, is the sensory, motor, and autonomic symptoms caused by myofascial trigger points. There has been some controversies regarding etiologies of TMD and MFP. Especially the issue of occlusal conditions has been a critical issue for long time. Despite much efforts, the results of studies regarding occlusal conditions were contradictory. These controversies might be mostly due to various factors resulting from the complex nature of TMD, however, inaccurate and inappropriate study design, selection criteria, methodologies also play significant roles. Recently, a computerized occlusal analysis system, T-Scan II which made it possible to reveal quantifiable time data and relative force data for analyzing occlusion, was introduced. Some authorities suggested that the concept of disclusion time and prolonged disclusion time of posterior tooth and MFP are related using T-Scan II. But the previous studies which used T-SCAN II are not reliable for they did not provide accurate diagnostic criteria of MFP. Morever they did not compare with controls, and had many other problems. The purpose of this study was to evaluate the relationship between MFP and prolonged disclusion time of posterior tooth, which is one of the occlusal factors of TMD, by selecting 30 subjects as the study group through strict criteria and comparing them with 38 controls using T-SCAN II, computerized occlusal analysis system. The results, statistically analyzed, are summarized as follows: 1. Cronbach ${\alpha}$ coefficient of repeated measurements of disclusion time was 0.92. 2. There were no statistically significant differences at repeated measured disclusion time of both side between control and study group. 3. There was no statistically significant diffefence in the disclusion time between right and left side. From the results above, we can suggest that there was no relationship between MFP and disclusion time, so irreversible treatments leading to the reduction of disclusion time for treating MFP would not be appropriate. However more controlled, large scaled study, which consider various occlusal factors, and quantification of symptoms using Helkimo index would be necessary in the future.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.1
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• pp.101-110
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• 2013

$T4K^{TM}$(Myofunctional Research Co, Australia) is one of the myofunctional appliance developed to be used in children of mixed dentition. Myofuncitonal appliance stimulate the facial, masticatory and tongue muscle and help to balance the muscular force. Labial bow included in the device exerts strength in excessively labial inclineded upper jaw, Lip bumper blocks strength of the mouth to prevent abnormal strength exerted in lower jaw, Tongue tag secures proper position of tongue, and additional exercise is not required for child patients. For the more, simpler design and softer texture of device prmoted cooperation of patients during use. This case report is to present the satisfactory results gained by using $T4K^{TM}$ on Class II patients. Comment 1. $T4K^{TM}$ was applied in Class II malocclusion patients of mixed dentition with expected space insufficient to gain facial improvement. 2. Excessive overjet, overbite were improved. 3. Main effects are regarded to have been achieved by development of lingual slant of upper jaw, labial slant of lower jaw, and lower part of jawbone. 4. Bad habits, such as mouth breathing, can also be adjusted.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.1
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• pp.58-64
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• 2012

Purpose: Dental emergencies vary from toothaches to oral and maxillofacial traumas. Because the number of dental emergency cases has increased recently, we analyzed characteristics of patients seen during the last 2 years, in an effort to find a trend. Methods: This study was carried out with emergency room patients visiting the Department of Oral and Maxillofacial Surgery from 2009 to 2010. Results: The total number of patients studied was 1,162; the ratio of males to females was 1.73:1. The most frequent age group was 0 to 9 years, followed by 20 to 29 years. Trauma (58.7%) was the most frequent cause followed by acute toothache, oral hemorrhage, infection, and temporomandibular (TMJ) disorder. In the trauma group, injuries of soft tissue and alveolus were prevalent. The most common causes of soft tissue injury were falls, safety violations and assault. The highest incidence of emergencies was seen in patients 0 to 9 years old (41.8%). The most common causes of jaw fracture were falls, assaults, and traffic accidents in that order. In the acute toothache group, most patients had pulpitis (41.2%). In the infection group, most had buccal space abscesses (40.0%). In the hemorrhage group, post-operative bleeding cases (80.5%) were the majority, and hemostasis was obtained mostly by pressure dressings. For the TMJ disorder group, masticatory muscle disorder (65.4%) was more common than TMJ dislocation. Conclusion: In this study, trauma was the most frequent reason for patients who visited the emergency room. However, acute toothache, hemorrhage, infection and TMJ disorders were also seen frequently. Dental emergency patients could be better treated by understanding patterns of dental emergencies and performing proper diagnoses.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.203-244
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• 1998

The human mandible is always under the condition of loading by the various forces extorted by the attached muscles. The loading is an important condition of the stomatognathic system. This condition is composed of the direction and amount of forces of the masticatory muscles, which are controlled by the neuromuscular system, and always influenced by the movement of both opening and closing. Mandible is a strong foundation for the teeth or various prostheses, nevetheless it is a elastic body which accompanies deformation by the external forces on it. The elastic properties of the mandible is influenced by the various procedures such as conventional restorative treatments, osseointegrated implant treatments, reconstructive surgical procedures and so forth. Among the treatments the osseointegrated implant has no periodontal ligaments, which exist around the natural teeth to allow physiologic mobility in the alveolar socket. And so around the osseointegrated implant, there is almost no damping effect during the transmission of occlusal stress and displacements. If the osseointegrated implants are connected by the superstructure for the stabilization and effective distribution of occlusal stresses, the elastic properties of mandible is restricted according to the extent of 'splinting' by the superstructure and implants. To investigate the change of elastic behaviour of the mandible which has osseointegrated implant prosthesis of various numbers of implant installment and span of superstructre, a three dimensional finite element model was developed and analyzed with conditions mentioned above. The conclusions are as follows : 1. The displacements are primarily developed at the area of muscle attachment and distributed all around the mandible according to the various properties of bone. 2. The segmentation in the superstructure has few influence on the distribution of stress and displacement. 3. In the load case of ICP, the concentration of tensional stress was observed at the anterior portion of the ramus($9.22E+6N/m^2$) and at the lingual portion of the symphysis menti($8.36E+6N/m^2$). 4. In the load case of INC, the concentration of tensional stress was observed at the anterior portion of the ramus($9.90E+6N/m^2$) and the concentration of tensional stress was observed at the lingual portion of the symphysis menti($2.38E+6N/m^2$)). 5. In the load case of UTCP, the relatively high concentration of tensional stress($3.66E+7N/m^2$) was observed at the internal surface of the condylar neck.