• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.441-447
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• 2007

Internal derangement of the temporomandibular joint(TMJ) is defined as an abnormal relationship of the articular disc to the condyle. Mandibular manipulation is one of the conservative treatments to be considered first to manage the patients with anterior disc displacement without reduction. Mandibular manipulation is used to increase articular mobility and to restore the displaced disc into an anatomically normal position. While Farrar's technique has been popularly used, Minagi et al., Mongini and Suarez introduced the manipulation technique conducted by the patients themselves. But there is no study on the efficacy of self-manipulation technique, comparing with conventional one. The aim of this study was to investigate the efficacy of the conventional and self-manipulation technique, which was modified to complement the previously described technique by Minagi et al., in the treatment of patients with anterior disc displacement without reduction. TMD patients, who visited Department of Oral Medicine of Seoul National University Dental Hospital from December, 2002 to November, 2004 and were diagnosed as anterior disc displacement without reduction by TMJ magnetic resonance imaging (MRI) were enrolled. Conservative treatments including physical therapy, exercise, behavioral therapy, stabilization splint therapy, and manipulation therapy were done to every single patient until the symptomsimproved enough to discharge the patient. The charts were reviewed retrospectively according to the type of manipulation. In the results, patients whose maximum mouth opening was more than 40 mm was higher in the self-manipulation group(69.9%) than in the conventional manipulation group(42.9%). But difference between two groups was not significant. According to the fact that we decided to discharge the patients whentheir mouth opening increased to more than 40 mm and subjective symptoms such as pain and discomfort were improved as well, treatment period of discharged patients was significantly shorter in the self-manipulation group($29.2{\pm}12.3$ weeks) than in the conventional manipulation group ($61.0{\pm}38.0$ weeks) (p<0.01). In conclusion, in the treatment of TMD patients with anterior disc displacement without reduction, the self-manipulation technique which is performed by patients themselves is an effective treatment modality for increasing the range of mouth opening and shortening the total treatment period.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.191-214
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• 2018

This research empirically analyzed the selection factors and the locational selection factors of the medical service facilities according to the gradual increase of the importance of the selection factors and the locational selection factors regarding the establishments of the small- and medium-sized hospitals according to the rapid changes of the socio-economic conditions. By analyzing the priority order according to the levels of the importance of each evaluation item factor through a research related to the selection factors and the locational selection factors of the small- and medium-sized hospitals and by drawing what the important factors that have the influences on the competitiveness of the pre-existent small- and medium-sized hospitals are through the classification of the real estate locational factors and the non-locational factors, the purpose lies in utilizing them as the basic data and materials for the opening strategies of the small- and medium-sized hospitals considering the special, locational characteristics according to the important factors of the selection factors of the small- and medium-sized hospitals, regarding the medical suppliers that have been preparing, for opening the new, small- and medium-sized hospitals. Based on the results of the preceding researches and the researches on the case examples, 28 evaluation factors were arrived at in terms of the level of the medical treatment, the medical services, the accessibilities of the hospitals, the conveniences of the hospitals, and the physical environment. And, regarding the 28 detailed evaluation factors that had been collected, through the interviews with the related experts, the 5 factors of the medical level, the medical service, the expertise of the hospital, the convenience of the hospital, and the physical environment were selected as the upper class evaluation factors. And, according to each upper class, a total of 28 low-part evaluation factors were selected. Regarding the optimal evaluation factors that were selected, the optimal locational factors were selected by carrying out an AHP questionnaire survey investigation with 200 medical experts as the subjects. Regarding the AHP analysis results, similarly with the case examples of the precedent researches, the levels of the importance appeared in the order of the medical level, the medical services, the accessibility of the hospital, the physical environment, and the convenience. And the factors that were related to the facilities of a hospital appeared low. The results of this research can be applied in providing the basis for the decision-makings regarding the selections of the locations of the small- and medium-sized hospitals in the future.

• 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 Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.414-421
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• 2004

This is a reprospective study on the care of odontogenic infections in admission patients with geriatric diseases. The study was based on a series of 480 patients at Dong San Medical Center, Wonju Christian Hospital and Il San Health Insurance Hospital, From Jan. 1, 2000, to Dec. 31, 2002. The Obtained results were as follows: 1. The systemic malignant tumor was the most frequent cause of the geriatric diseases with odontogenic infectious diseases, and refractory lung disease, systemic heart disease, type II diabetes mellitus, cerebrovascular disease, bone & joint disease, senile psychologic disease were next in order of frequency. 2. Male prediction(57.5%) was existed in the odontogenic infectious patients with geriatric diseases. But, there were female prediction in senile psychologic disease, systemic heart disease and cerebrovascular disease. 3. The most common age group of the odontogenic infectious patient with geriatric disease was the sixty decade(47.9%), followed by the seventy & eighty decade in order. 4. In the contents of chief complaints on the odontogenic infectious patients with geriatric disease, peak incidence was occurred as toothache(52.7%), followed by extraction wish, tooth mobility, oral bleeding, oral ulcer, fracture of restoration, gingival swelling in order. 5. In the diagnosis group of odontogenic infectious diseases, periodontitis, pulpitis & periapical abscess were more common. 6. In the treatment group of odontogenic infectious diseases, the most frequent incidence(34.2%) was showed in primary endodontic treatment (pulp extirpation, occlusal reduction and canal opening drainage) and followed by scaling, incision & drainage, only drugs, pulp capping, restoration in order.

• Journal of Distribution Science
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• v.4 no.1
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• pp.121-140
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• 2006

This study has explored a number of problems arising from distribution restrictions and the ways to improve efficiency. As matters stand, since the cooperation between larger stores and local retailers is limited due to the nature of the market, the current situations call for bottom up restrictions such as the active promotion of smaller merchants and traditional marketplaces, the enhancement of the competitiveness of smaller merchants and manufacturers through the establishment of a customized consulting support program for individual shops, and the continual support for traditional marketplaces with facilities and management modernization. The government should maintain the optimal balance between the efficiency and effectiveness of the distribution industry through such bottom up restrictions as shown above, rather than the top down restrictions primarily relying on the hurdles to the establishment of stores. The problems raised in this study include: (i) the decline of traditional marketplaces and the alleged over saturation of stores; (ii) the possible abuse of indiscreet restrictive measures; (iii) the harmful effects of the monopoly or oligopoly by larger distributors; and (iv) the lack of systematic programs to promote development. The ways to improve efficiency are: (i) the establishment of the policies to specialize and nurture traditional marketplaces; (ii) the effort to prevent the injury arising from monopoly; (iii) the two tire strategies for the coexistence of larger and smaller businesses; and (iv) the administration of joint sales promotion and training.

• 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.40 no.2
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• pp.55-62
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• 2015

Purpose: The aims of this study were to evaluate the differences in subjective symptoms, clinical characteristics, distribution according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) subgroup, psychological profile of TMD patients, and to identify the prevalence and trend according to age. Methods: A total of 1,052 patients (261 men and 791 women; mean age, $34.40{\pm}15.73$ years) who visited the Orofacial Pain Clinic of the Department of Oral Medicine, Seoul National University Dental Hospital complaining of TMD symptoms of were evaluated. All patients were questioned for medical history, clinical symptoms and contributing factors. Clinical examination and patient grouping based on RDC/TMD was conducted. Radiographies were taken. The Korean version of RDC/TMD axis II and Symptom Checklist-90-Revision (SCL-90-R) were administered to evaluate pain-related disability level and psychological status of the patients. Results: Prevalence peaked in the 20-year-old age group. There were more women than men in all groups. The highest T-score among SCL-90-R dimensions was somatization in each group, except for teenagers who showed the highest T-score in interpersonal sensitivity. The 30-year-old age group showed the highest distribution of high disability based on the graded chronic pain scale. Age was positively associated with pain intensity (r=0.100), number of positive muscles on palpation (r=0.137) and negatively associated with maximum mouth opening (r=-0.168). Conclusions: Subjective symptoms and clinical characteristics of TMD patients show distinct tendencies according to different age groups. Treatment should be customized and personalized according to age for efficient symptom resolution and patient satisfaction.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.10-21
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• 2018

This study analyzes difficulties of enterprise activities in Chinese construction market by surveys on early entrants and interviews with experts. This study also suggests future strategy to enter the market by using inducement coefficient model. Korean construction companies in China are under heavy pressure to maintain requirement of licenses, despite recent deregulation. They are in dire predicament for market entry due to the Foreign Direct Investment System. It is almost impossible to participate in public projects and also it is not easy to do PPP projects. Therefore, Korean government should make more efforts to solve those issues through negotiations in FTA and GPA. For future expansion in Chinese construction market, it is highly recommended to boost cooperation models between Korea and China according to the empirical results of inducement coefficient model. Korean companies should collaborate with Chinese companies in some fields: smart city, environment and water treatment. Also, Korean government should support Korean companies by diplomatic means such as requesting for further opening of China's market. In GPA or GATS negotiation, Korean government should ask Chinese government that Korean companies can obtain order independently (without joint venture with Chinese companies) in China. Lastly, Korean construction companies should participate in construction projects ordered by international organizations such as ADB, AIIB.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.357-366
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• 2013

This study is designed to evaluate the treatment outcome of occlusal stabilizing splint and to assess follow-up study of condylar bony changes using cone beam computed tomography(CBCT) in adolescents patients (12-19 years) with TMJ osteoarthritis(OA). 167 eroded condyles in 149 subjects were chosen among the patients who presented to the Department of Oral Medicine of Pasan National University Hospital, diagnosed as TMJ osteoarthritis by clinical exam, x-ray and CBCT from 2009 to 2012. They were treated conservatively with physical therapy, medication, behavioral therapy and occlusal stabilizing splint therapy. After average 9 months, CBCT was retaken and subjective symptoms and clinical findings were investigated. Condyle bony changes were classified by unchanged, less severe and more severe. The obtained results were as follow: 1. Pain, Noise, LOM(Limitation of motion) and MCO(Maximum comfortable opening) measurement of TMJ OA patients were markedly improved after conservative treatment. 2. In the occlusal stabilizing splint therapy group, Pain and LOM were statistically significant improved than non-occlusal stabilizing splint therapy group. 3. In the acute occlusal stabilizing splint therapy group, Pain and LOM were remarkably improved. 4. In comparison of CBCT1 and CBCT2 images, the transition of bone changes to lesser severe was most commonly in joint with erosive change. 5. In the non-occlusal stabilizing splint therapy group, the transition of condylar bone changes from erosion to more severe was many than occlusal stabilizing splint therapy group.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.528-543
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• 2005

Statement of problem: Repeated delivery and removal of abutment cause some changes such as wear, scratch or defect of hexagonal structure. It may increase the value of rotational freedom(RF) between hexagonal structures. Purpose: The purpose of this study was to evaluate surface changes and rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment after repeated delivery and removal under SEM and toolmaker's microscope. Materials and methods: Implant systems used for this study were 3i and Avana. Seven pail's of implant fixture, abutment and abutment screws for each system were selected and all fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. Each one was embedded beneath the platform of fixture. Surfaces of hexagonal structure before repeated closing and opening of abutment were observed using SEM and rotational freedom was measured by using toolmaker's microscope. Each abutment was secured to the implant future by each abutment screw with recommended torque value using a digital torque controller and was repeatedly delivered and removed by 20 times respectively. After experiment, evaluation for the change of hexagonal structures and measurement of rotational freedom were performed. Result : The results were as follows; 1. Wear of contact area between implant fixture and abutment was considerable in both 3i and Avana system. Scratches and defects were frequently observed at the line-angle of hexagonal structures of implant fixture and abutment. 2. In the SEM view of the external hexagon of implant fixture, the point-angle areas at the corner edge of hexagon were severely worn out in both systems. It was more notable in the case of 3i systems than in that of Avana systems. 3. In the SEM view of the internal hexagon of abutment, Gingi-Hue abutment of 3i systems showed severe wear in micro-stop contacts that were machined into the corners to prevent rotation and cemented abutment of Avana systems showed wear in both surface area adjacent to the corner mating with external hexagon of implant fixture. 4 The mean values of rotational freedom between the external hexagon of the implant fixture and internal hexagon of abutment were 0.48$\pm$0.04$^{\circ}$ in pre-tested 3i systems and 1.18$\pm$0.25$^{\circ}$ after test, and 1.80$\pm$0.04$^{\circ}$ in pre-tested Avana systems and 2.61$\pm$0.16$^{\circ}$ after test. 5. Changes of rotational freedom after test shouted statistical)y a significant increase in both 3i and Avana systems(P<0.05, paired t-test). 6. Statistically, there was no significant difference between amount of increase in the rotational freedom of 3i systems and amount of increase in that of Avana ones(P>0.05, unpaired t-test). Conclusion: Conclusively, it was considered that repeated delivery and remove of abutment by 20 times would not have influence on screw joint stability. However, it caused statistically the significant change of rotational freedom in tested systems. Therefore, it is suggested that repeated delivery and remove of abutment should be minimal as possible as it could be and be done carefully Additionally, it is suggested that the means or treatment to prevent the wear of mating components should be devised.