• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.269-279
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• 1987

The purpose of this study was to obtain basic data needed to clinical diagnosis and treatment by investigating the occlusal wear facets and those related factors. Sixty-six subjects, ranging from 24 to 26 years of age without symptoms of stomatognatic system, were selected from dental students in Chosun University. The area of occlusal wear facets was measured and twenty subjects were selected, and divided into two groups (Group I and Group II). The Group I had small facet areas, and the Group II had large facet areas. These two groups were investigated into right and left side wear facet areas, vertical overlaps, occlusion types of working side, masticatory muscle activities, and asymmetry of right and left side masticatory muscle function. The results were as follows: 1. The average wear facet areas of all subjects was $22.84{\pm}88.95mm^2$, and Group I and Group II were $96.12{\pm}32.00mm^2$ and $372.94{\pm}65.63mm^2$ respectively. 2. The right and left wear facet areas of Group I were $46.72{\pm}14.36mm^2$ and $49.40{\pm}21.46mm^2$ respectively. The right and left wear facet areas of Group II were $175.27{\pm}45.75mm^2$ and $185.69{\pm}45.37mm^2$ repsectively. 3. The vertical overlap of Group I and Group II was $3.88{\pm}0.81mm$ and $2.88{\pm}1.14mm $ respectively. 4. Most of the Group I had Canine protection occlusion (80%), and most of the Group II had Group function occlusion (80%). 5. The masticatory muscle activities at rest position, maximum bite, habitual chewing, right and left unilateral chewing were greater in Group II than in Group I, especially in the masseter muscle of working side at right and left unilateral chewing. (P<0.01). 6. The asymmetry of right and left wear facets and masticatory muscle activities were greater in Group II than in Group I. (P<0.01).

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.37-44
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• 1991

The author has synchronously recorded average electromyographic activities of temporalis anteriors and masseter muscles and the maximum bite force on the mandibular first molar on the prferred chewing side. These activities were recorded in order to study the EMG activity pattern of the working side and the balancing side to maximum bete force and functioning state of muscle in 30 patients with TMD and in 30 healthy subjects as controls. The results were as follows : 1. The maximum bite force on the mandibular first molar on the preferred chewing side was 20.63kg in TMD patients and 53.30kg in the healthy subjects(p<0.01). The maximum bite force in TMD patients was 38.7% of the healthy subjects. 2. The average electromyographic activities of temporalis anterioris and masseter muscles on the working side and the balancing side during maximum bite force were lower in TMD patients than in the healthy subjects(p<0.01). The average electromyographic activities of each muscle in TMD patients were 61.0%-62.8% of the healthy subjects. 3. The proportionalities of average electromyographic activities of temporalis anteriors and masseter muscles on the working side and the balancing side to maximum bite force were greater in TMD patients than in the healthy subjects(p<0.01). 4. Between the working side and the balancing side, the proportionality of average electromyographic activity of temporalis anterior to maximum bite force on the working healthy subjects (p<0.01). The proportionality of average electromyographic activity of working side and the balancing side in both groups (p<0.05).

• Journal of dental hygiene science
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• v.7 no.3
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• pp.179-185
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• 2007

The purpose of this study targeted on high school student in the department of liberal arts, industry in Daegu metropolitan city, is to get basic data necessary for the development of dental educational program, to discern prevention and treatment of temporomandibular joint disorder by observing the situation temporomandibular joint disorder and contribution element, of relationship of school life stress The results are as follows.: 1. The percentage of occurring temporomandibular joint disorder in the high school resulted in a joint noise at 61.8% and joint dislocation 6.9%, sharp pain 47.5% at time of chewing. 29.8% at the time of the non-chewing, lockjaw 11.3%, a headache appeared at 40.4%.2. In the contribution factor of occurring temporomandibular joint disorder, the cause of joint noise was the clench one's teeth, lip and cheek clench, For the pain at the time of chewing clench one's teeth, one side chewing, over-chewing, lip clench, sideways sleeping showed the difference. (P < 0.01) For the pain at the time of non-chewing, clench one's teeth, bruxism, one side chewing, lip and cheek clench were similar, and for the lockjaw, clench one's teeth, bruxism, sideways sleeping showed the difference. The plum evil thing period at time of the fault writing that statistically showed the difference. For the headache, the contribution factors were the all bad habits mentioned above excluding one side sleeping.(P < 0.01, P < 0.05). 3. The rate of experiencing temporomandibular joint disorder by oral and maxillofacia was 13.4% in industrial department, and 19.6% in liberal arts. And for the factor of wound was that exercise 26.8%, others 24.4%, fall-down 19.5%. And for the industrial, exercise 44.4%, fall-down 22.2%, others 14.9%. The treatment experience appeared at 5.0% in industrial department, 2.9% in liberal arts. And for the medical institutions, liberal arts were dental clinic 50%, orthopedics 50%, and the industrial department orthopedics 40%, oriental medicine clinic 30%, dental clinic 30%. 4. In case of temporomandibular joint disorder, there were no difference by grades or educational background. And at the time of chewing or non-chewing showed similar difference.(P < 0.01). 5. Compared to stress in the high school, it generally showed higher in liberal arts than in industrial department due to school record. Its scope was $3.75{\pm}1.14$ in liberal arts, $3.01{\pm}1.23$ in industrial department. 6. The school record, school life, stress problems by teachers, chewing/non-chewing pain of temporomandibular joint disorder, joint noise had a similar correlation.(P < 0.01, < 0.05).

• Journal of Oral Medicine and Pain
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• v.31 no.2
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• pp.167-176
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• 2006

Recent studies have shown that there are significant increasing facial asymmetry using 3-dimensional imaging. This study use panorama view and PA cephalograph that were low in price and make good use in dentistry. For this study, 35 persons without remarkable malocclusion were selected, they had panorama view and PA cephalograph, make written questionnaire about facial asymmetry cognition and masticatory pattern. Data obtained were statistically processed by the SPSS Windows program and the results of this study were as follows: 1. There were significant difference between Rt and Lt. on Co-Go, Co-Ag, Co-Go-Ag, Go-Me- Ag. 2. In panorama view, There were significant difference between Rt. and Lt Co-Ag that chewing right side, Rt. and Lt. Co-Go that chewing left side, 3. In PA cephalograph view, There were significant difference in Rt. and Lt. Cg-Go, Rt. and Lt. Co-Ag that chewing right side, Rt. and Lt. Cg-Go that chewing left side 4. There were significant difference in Rt. and Lt. Co-Go, CO-si-CR, go-ME-Ag that cogniting facial asymmetry.

• 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.

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.153-168
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• 1994

The aim of the present study was to investigate a relation between occlusal wear area and occlusal contact patterns. For the purpose, occlusal wear area were measured in 58 dental students and in 129 patients with temporomandibular disorders(TMDs) from dental casts. Teeth used in this study were from canine to second molar on both sides in upper arch, totally ten. Occlusal wear area on casts was marked by pencil and photocopies, and then, the area was measured with planimeter. Occlusal relation was clinically examined with regard to Angle's classification, chewing side preference, lateral guidance pattern and bruxing and/or clenching habit. T-Scan, electronic occlusal contact analyzer, was used to record occlusal contact number, contact force, contact time and occlusal balance that is TLR(total left-right statistics) during tooth contact. All measurement were repeated 3 times and the average value was used for data processing. The obtained results were as follows : 1. Mean value of occlusal wear area did not differ significantly between dental students and patients. 2. There ws not significant difference in wear area between chewing side and non-chewing side in both groups. 3. Occlusal wear area was significantly increased with age in both groups. 4. Three subgroups divided by Angle's classification did not show any difference in occlusal wear area among them, but three subgroups divided by lateral guidance pattern showed slightly significant difference between canine guide subgroup and group function subgroup in patients. Occlusal wear ares\a in group function subgroup wear larger than canine guide subgroup. 5. Mean value of wear area in patients with bruxing and/or clenching habit did not differ from those in patients without such habit. 6. Correlationship among items related to occlusal contact pattern were highly consistent and significant in dental students and only one item significantly correlated with occlusal wear area was tooth contact time.

• Journal of Nutrition and Health
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• v.46 no.3
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• pp.285-295
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• 2013

The purpose of this study was to examine the characteristics of the dietary intake of Korean elderly according to chew-ing ability using data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted during 2007-2010. Among subjects aged 65 years and over, more than half, 54.3% of elderly people, were classified as the difficulty in chewing group (DC). The DC group had lower nutrients and food intakes than those of in the no difficulty in chewing group (NDC). Findings showed that subjects in the DC group consumed fewer foods, especially fruits and vegetables. In addition, the DC group had significantly lower intakes of pan-fried food, stir-fried food, braised food, and seasoned-cooked vegetables, which could not be easily cooked or chewed. On the other hand, the number of soups and stews included in the top 30 largely consumed dishes were higher in the DC group than in the NDC group. No difference in numbers of daily meal/snack intake was observed between the two groups, however, the DC group had lower numbers of side-dishes compared to the NDC group. Fewer side-dishes per meal could be related to lower intakes of nutrients in dietary quality. Findings of this study demonstrated that dietary intake was influenced by chewing ability of elderly Korean people. Therefore, study of factors affecting dietary intake such as convenient cooking methods to decrease cooking time and skills to extend preservation and storage time of foods will necessary. In addition, development of food products and new techniques of cooking considering health status, chewing, and swallowing ability is required for the elderly, followed by establishment of standards for senior-friendly food products.

• Journal of Oral Medicine and Pain
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• v.24 no.1
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• pp.37-47
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• 1999

This study was performed to investigate the factors related to vibration of temporomandibular joint during mandibular opening movement. For this study, 144 patients with temporomandibular disorders were randomly selected. Angle's classification, lateral guidance pattern, range of maximal mouth opening, preferred chewing side, and affected side were investigated clinically. Mandibular torque rotational movement during opening was recorded with $BioEGN^{(R)}$ and vibration of temporomandibular joint during opening was recorded with $Sonopak^{(R)}$. After clinical diagnosis was made, visual analogue scale(VAS) was used for evaluation of clinical progress of the subject's chief complaints. The author calculated VAS treatment index(VAS Ti) from the record of VAS. The more VAS Ti was, the less remission of subjective symptom was, The data were analyzed with SAS/Stat program and the results of this study were as follows: 1. There were no significant difference in all the variables of joint vibration by age and sex. 2. Integral and peak amplitude in patients of Angle's class I were higher than those of class II or III patients. Integral in patients of group function was higher than that in patients of canine guidance or other types of lateral excursion. 3. As to Angle's classification or lateral guidance type, there were almost not significant difference between subgroup of same class or type and subgroup of different class or type on both sides. And there were also almost not difference between one side and the other side related to preferred chewing side or affected side. 4. Patients with disk displacement with reduction showed higher value of integral and peak amplitude than any other patients. 5. Joint vibration variables significantly correlated with VAS Ti of pain. with clinical range of mouth opening, and with ingredients of mandibular torque rotational movement.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.328-342
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• 1999

This study was performed to investigate the factors related to tooth wear. For this study, 78 patients with temporomandibular disorders and 76 dental students without any signs and symptoms of temporomandibular disorders were selected as the patients group and as the normal group, respectively. Preferred chewing side, Angle's classification, lateral guidance pattern, head and shoulder posture were observed clinically. Electromyographic activity of anterior temporalis and masseter muscle were recorded with $BioEMG^{(R)}$ and occlusal status were recorded with $T-Scan^{(R)}$. Wear facet area of each tooth was measured from working model of upper arch corresponding to the occlusal status from T-Scan. Wear facet area were measured with planimeter in $mm^2$. Total area were divided into incisal, canine, posterior tooth area. Anterior wearfacet area was incisor area plus canine area, and unilateral area was anterior area plus posterior area. The data collected were analyzed by SAS statistical program and the results of this study were as follows: 1. There was no significant difference between the two groups in total werafacet area, and male subjects showed tendency to have larger area in the normal group but female subjects showed tendency vice versa. 2. There was no significant difference related to preferred chewing side and Angle's classification, however some difference was observed by lateral guidance pattern. Anterior wear facet area in subjects of canine guidance was the largest in the three subgroups. 3. Subjects with head tilting to right side had larger posterior and total area, and subjects with higher shoulder in right side had larger canine and anterior area than any other subgrous. 4. Electromyographic activity of masseter muscle was more correlated with wear facet area than anterior temporalis muscle, and tooth contact number and force were significantly correlated with wear facet area, but the most important factor affecting tooth attrition was age.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.407-420
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• 1995

This study was performed to evaluate and compare conservative treatment results by several parameters such as age, sex, symptom duration, type and timing of joint sound, parafunctional habits, splint type, and diagnostic classification. There have been too many articles reporting long term results of conservative treatment but articles related to comparison of treatment results by patients' self-evaluation have been rarely reported. For this study 258 patients with temporomandibular disorders(TMDs) were selected and examined by routine diagnostic procedure for TMDs. The subjects were classified into 5 TMDs subgroups ad treated with conservative treatments involving splints, physical modalities, jaw exercises, and counseling. Visual analogue scale(VAS) about pain, joint sound, and mouth opening limitation was recorded respectively during treatment period. From the VAS data and treatment duration, VAS treatment index(VAS Ti) was calculated. The obtained results were as follows : 1. Pain was the most frequent main symptom in subjects with temporomandibular disorders, and main symptom for mouth opening limitation was comparatively less than for pain or sound in disk displacement with reduction group or in degenerative joint disease group. 2. Degenerative joint disease group had the most poor treatment results and highest occlusal index of Helkim's index. 3. Good prognosis for conservative treatment was observed in acute group, under 6 months than chronic group, 6months over in symptom duration, and subjects with 40 years over in age showed the most poor prognosis. 4. Subjects treated with anterior repositioning splint had better treatment results than subjects treated with centric relation splint, but statistical significance in VAS Ti and treatment duration was not observed. 5. Treatment results according to affected side, types and point of joint sound did not show consistent statistical results. 6. The result for conservative treatment was observed poor in subjects with bruxism and clenching. 7. In studying coincidence between preferred chewing and affected side, frequency of preferred chewing side, in unilateral affection, was higher in ipsilateral than in contralateral side.