• The Journal of the Korean dental association
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• v.56 no.6
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• pp.324-332
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• 2018

A mouthguard is a protective device normally worn on the upper jaw, to reduce injures to the teeth, jaws and surrounding soft tissues. It has a definite role in preventing injuries to the teeth and face and for this reason it is strongly recommended for all sporting activities where there is a risk of trauma to the teeth and associated structures. Mouthguards can be effective in reducing impact force to the teeth, and attributed to enhancement of postural control and muscle performance during teeth clenching. Although there is evidence that mouthguards reducing impact force to the teeth, and prevent orofacial trauma occurrence during sport practice, the influence of this device on athletic performance has not been systematically quantified. Nevertheless, wearing a dentally fitted laminated mouthguard of at least 3 mm thickness can be strongly recommended during sport practice.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2439-2441
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• 1998

In this research, the sensor and control system for self detecting masticatory muscle relaxation appliances. A strain gauge is used to measure a strength of tooth clenching force. A bridge circuit and voltage amplifier is designed to amplify measured signals and RF transmitter and receiver is also designed to communicate inner and outer mouth device. The experiments are performed to show the effectiveness of designed system.

• Journal of Oral Medicine and Pain
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• v.7 no.1
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• pp.32-40
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• 1982

Functional disorders of the temporomamdibular joint and masticatory system were investigated in 209 men and 110 women, ranging form 20 to 30 years old, with a method devised by Agerberg and Carlsson. The investigated persons were dental students of the School of Dentistry, Seoul National University and student nurses of the School of Medicine, Seoul National University. The obtained results were as follows : 1. Facial pain and headache were reported by 32%. 2. Pain on gaping was localized mainly to the temporomandibular area and was noted in 8%. 3. Chicking of the temporomandibular joints was reported by 26%, somewhat more often by males. 4. Clenching of the teeth was relatively common in men and biting of the lip was comman in women. 5. Prevalence of mandibular dysfunction was found in 53%.

• Journal of Oral Medicine and Pain
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• v.45 no.4
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• pp.120-123
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• 2020

The causes of tongue pain and discomfort include systemic disease, malnutrition, mental illness, fungal infection, and neuropathy. Three postmenopausal women reported burning sensations and stiffness of the tongue for various periods, from one month to four years. There were no objective etiological factors to cause the tongue pain and discomfort. Muscular tenderness upon palpation of masticatory muscles, sternocleidomastoid, trapezius, and tongue were observed. Physical therapy approaches such as moist hot pack, ultrasound, and myomonitor were performed on three patients with tongue pain, just as for temporomandibular joint disease. Additional botulinum toxin injection therapy was applied to one patient who displayed a clenching habit. All three patients showed a marked improvement in their tongue symptoms after the muscle relaxation and botulinum toxin injection therapy.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.89-101
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• 1996

This study was performed to investigate influence of the changes of head posture on resting electromyographic (EMG) activity in anterior temporalis, masseter, sternocleidomastoid muscle and trapezius, and on status of occlusal contacts. For this study twenty-nine patients with temporomandibular disorders(TMD) and thirty dental students without any masticatory symptoms were selected as patients group and control group, respectively. EMG activity($\mu$V) at rest was observed in four kind of head postures such as natural or normal head posture(NHP), forward head posture(FHP), upward head posture(UHP), downward head posture(DHP), and in NHP and FHP, EMG activity with flat occlusal splint was also checked. BioEMG$^\textregistered$(Bioelectromyograph, Bioresearch Inc., USA) was used to record EMG activity in the above four muscles with eight locations on both sides. The author used T-Scan$^\textregistered$(Tekscan Co., USA) system to investigate the changes of oclusal contats on clenching in the four head postures about number, force, time(duration) and total left-right statistis(TLR, occlusal stability crossing left-right dental arch on clenching). For taking in upward or downward head posture, head was inclined $10^{\circ}$ upward or downward and CROM$^\textregistered$ (cervical-range-of motion, Performance attainment Inc., USA) was used to maintain same posture during the procedure. The results obtained were as follows : 1. For resting EMG activity, anterior temporalis did not show any difference by change of head posture, but masseter and sternocleidomastoid muscle showed higher value of EMG activity in FHP and UHP, and trapezius showed higher value of EMG activity in FHP and DHP. 2. EMG activity of trapezius was higher than that of any other muscles in NHP, FHP, and DHP, but in UHP, the activity was the lowest reversely. 3. Patients group showed higher EMG activity than control group did in all the muscles in NHP. And significant difference between the two groups were also observed in anterior temporalis in FHP, in sternocleidomastoid muscle in UHP, and in sterno-cleidomastoid muscle and trapezius in DHP with higher activity in patients group. 4. There was no change of EMG activity in NHp with splint, but EMG activity in anterior temporalis and masseter was decreased in FHP with splint. 5. In general, status of occlusal contacts was not changed with head posture in all subjects, and difference between patients group and control group was only noted for number and force of tooth contact in UHP and DHP with more value in control group. 6. Correlationship between EMG activity and number ad force of tooth contacts was shown negatively with regard to masseter in NHP, and trapezius in UHP and DHP.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.333-338
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• 2013

Purpose: A growing number of studies have been providing evidence for neural connections between the auditory and somatosensory systems that might be a critical part of the mechanisms underlying certain forms of tinnitus. The aim of this study was to investigate the effect of temporomandibular joint (TMJ) movements on tinnitus. Methods: One hundred sixty-three tinnitus patients participated in this study. All patients underwent a thorough audiological examination including pure-tone audiometry, tinnitus handicap inventory, and evaluation of tinnitus loudness, frequency and severity on a visual analog scale. Somatic testing consisting of nine forceful jaw muscle contractions was performed to evaluate the effect of TMJ movements on modulation of tinnitus. Results: 66.9% of patients had unilateral tinnitus. Somatic testing modulated tinnitus loudness in 125 ears (57.6 %) of 217 ears tested. An increase in tinnitus loudness was observed more often than a decrease. Loudness was most commonly increased by opening and clenching jaw. Tinnitus could be induced by opening, clenching and deviating jaw to the left. Conclusion: Our study showed evidence that TMJ movements may aggravate and even evoke tinnitus and somatic testing can be used for evaluating if stimulation of the TMJ induces or aggravates tinnitus.

• Journal of Oral Medicine and Pain
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• v.32 no.1
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• pp.91-104
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• 2007

An epidemiologic investigation was carried out to determine the prevalence of symptoms of temporomandibular disorders in college students that aged 19-31 years. 460 students were investigated with a questionnaire from September to December 2006. The obtained results were as follows : 1. The prevalence of symptoms of temporomandibular disorders was 80.6%. 2. The most frequently complained symptom was headache and joint sound was the next one without distinct difference between men and women. 3. While the rate of occurrence of symptom of acute malocclusion decreased with age in men, that of TMJ pain during chewing or speech increased with age in women. 4. Symptoms including TMJ pain during mouth opening, chewing or speech, TMJ fatigue and acute malocclusion occurred significantly more frequently in women than in men. Contributing factors including resting cheeks on hands, stressful state, gum chewing, insomnia and clenching occurred significantly more frequently in women than in men. 5. There was a highly significant relationship between symptoms and contributing factors including resting cheeks on hands, stressful state, unilateral chewing, insomnia and clenching. 6. There was a highly significant relationship between symptoms and general personality.

• Journal of Oral Medicine and Pain
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• v.38 no.2
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• pp.175-185
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• 2013

Objective : Condyle hypoplasia in temporomandibular joint(TMJ) is often observed in several radiographic views. Mandibular Condyle hypoplasia is frequently confused with osteoarthritis with bony changes in TMJ. This paper investigated clinical characteristics of mandibular condyle hypoplasia as compared with TMJ osteoarthritis. Material and method : 276 patients with TMD were taken clinical and radiological examination and were divided into study group, 189 patients diagnosed with mandibular condyle hypoplasia, and control group, 87 patients diagnosed with TMJ osteoarthritis. And clinical features(Onset, Overjet, Overbite, Noise, Locking, NAS of noise, LOM, pain, MCO, and site of diagnosis and pain)of the two groups were compared. Results : 1. Mandibular condyle hypoplasia and TMJ osteoarthritis were similar in many of the clinical features. 2. Mandibular condyle hypoplasia concordance rates of the radiographic diagnosis site and the pain site was significantly lower than TMJ osteoarthritis. 3. Bilateral mandibular condyle hypoplasia group had more occlusal discomfort, and clenching habits than unilateral mandibular condyle hypoplasia group. 4. Unilateral mandibular condyle hypoplasia group had more unilateral chewing habits and LOM than unilateral TMJ osteoarthritis group. Unilateral TMJ osteoarthritis group had more morning stiffness and higher concordance rates of the radiographic diagnosis site and the click sound site than unilateral mandibular condyle hypoplasia group. 5. Bilateral mandibular condyle hypoplasia group had more usual headaches and overjet than bilateral TMJ osteoarthritis group. Conclusion : Mandibular condyle hypoplasia has somewhat distinguishing clinical characteristics as compared with TMJ osteoarthritis.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.87-101
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• 2012

Bruxism is extensively defined as a diurnal or nocturnal parafunctional habit of tooth clenching or grinding. The etiology of bruxism may be categorized as central factors or peripheral factors and according to previous research results, central factors are assumed to be the main cause. Bruxism may cause tooth attrition, cervical abfraction, masseter hypertrophy, masseter or temporalis muscle pain, temporomandibular joint arthralgia, trismus, tooth or restoration fracture, pulpitis, trauma from occlusion and clenching in particularly may cause linea alba, buccal mucosa or tongue ridging. An oral appliance, electromyogram or polysomnogram is used as a tool for diagnosis and the American Sleep Disorders Association has proposed a clinical criteria. However the exact etiology of bruxism is yet controversial and the selection of treatment should be done with caution. When the rate of bruxism is moderate or greater and is accompanied with clinical symptoms and signs, treatment such as control of dangerous factors, use of an oral appliance, botulinum toxin injection, pharmacologic therapy and biofeedback therapy may be considered. So far, oral appliance treatment is known to be the most rational choice for bruxism treatment. For patients in need of esthetic correction of hypertrophic masseters, as well as bruxism treatment, botulinum toxin injection may be a choice.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.35-44
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• 1997

mastication is basically regulated by central pattern regulalor(CPG) of brain system, target organ output from CPG is modulated by oral sensory feedback, anterior cross bite pattern infuluence the feedback mechanism and change muscle activity and jaw movement. The purpose of this study was to investigate differnce anterior cross bite group from normal group, the selected sample groups were 30 normal patient, 30 anterior cross bite patient. EMG and EGN of Biopak system were used for this study The following results were obtained 1 In resting slate of mandible, anterior cross-bite showed the higher muscle activities in all the muscle.(exception:left digastric muscle) than normal group. 2. In clenching state, No significant difference in muscle activities of normal group and anterior cross bite group was noticed 3. In swallowing state Normal group showed the higher muscle activities in left and right masseter muscle, right posterior temporal muscle. 4. In maximum opening and closing velocity, normal group showed the higher value than anterior cross-bite. 5. In the mean value of the maximum opening,the maximum anterior posterior movemenl from centric-occlusion, the lateral deviation from centric occclusion, normal group showed the higher value than anterior cross-bite group.