• Journal of Oral Medicine and Pain
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• v.32 no.3
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• pp.337-346
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• 2007

This study aimed to evaluate a relation of bruxism with clinical effects of botulinum toxin type A(BTX-A) injection. 5 bruxers and 5 nonbruxers with bilateral masseter hypertrophy were participated in this study. After injecting 25 unit of BTX-A(Allergen Inc, $Botox^{(R)}$) into each masseter muscle, the thickness of masseter(Mm) and anterior temporalis(Ta) muscles was measured by ultrasonography and the maximum bite force was evaluated during a 9-month period. Self-estimation on the recovery of occlusal force during mastication was done as well. Regardless of presence of bruxsim, all subjects showed significantly reduced Ms thickness(p<0.001) and maximum bite force at $1^{st}$ molars(p=0.027) with their peak at 3 months after injection, which then started to return. No significant difference was observed in Ta thickness and the bite force at the central incisors. While self-estimated occlusal force was the least at 2 weeks after injection and then rapidly returned to the baseline level with full recovery at the time of 6 to 9 months after injection, the maximum bite force measured by bite force recorder did not recover the original value, particularly in the nonbruxer group. It is assumed that nocturnal bruxism can influence recovery of atrophic masseter and decreased occlusal force due to BTX-A injection. These findings suggest a need of occlusal appliance to control bruxism or clenching habit for longer clinical effect of BTX-A injection.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.411-426
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• 2005

The purpose of this study was to investigate the effects of occlusal condition and clenching level on the mandibular torque rotational movement. For this study, healthy 14 men without any symptoms and signs of temporomandibular disorders were selected. Mandibular torque rotational movement was observed in each circumstance of combination of three occlusal conditions such as natural dentition, with wafer of 3.6 mm thickness, and wafer with resin stop of 14 mm thickness total during hard biting of bite stick at maximum voluntary contraction(MVC) and 50% of MVC level of surface EMG activity of masseter muscle. Electromyographic activity and mandibular torque rotational movement were observed using BioEMG and BioEGN in $BioPak^{(R)}$ system. Each biting movement in each circumstance was composed of clenching one time and hard biting of wooden stick two times. The observed items were opening distance, velocity and amount of torque rotational movement in mandibular movement, and the data were statistically processed with $SPSS^{(R)}$ windows (ver.10.0). The results of this study were as follows: 1. There were no differences in the mandibular movement distance between those value in both biting sides, and between those in both clenching forces, but the mandibular velocity showed a different results by clenching force. For the amount of torque rotational movement, there were no difference in the value of the frontal plane but some significant difference was in the value of the horizontal plane by biting side. 2. The mandibular movement distance and the mandibular velocity in both planes were higher by maximum voluntary contraction than those by half maximum voluntary contraction, and amount of torque rotational movement in the horizontal plane was also increased by maximum voluntary contraction. 3. The opening distance in both planes were decreased with the increase of vertical dimension of occlusion, namely, by the occlusal appliances, and this pattern was also showed in the mandibular velocity in case of hard biting by maximum voluntary contraction. However, the amount of torque rotational movement were not different by the increase of vertical dimension of occlusion. 4. The value of angle and distance of the torque rotational movement in the hard biting of wooden stick were generally higher than those in the clenching without wooden stick in both planes without regard to occlusal conditions and/or clenching forces.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.201-214
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• 2005

Age estimation is fundamental and important in personal identification with forensic medicine and dentistry. Recently, a lot of studies using various part of the body have been done for age estimation. Age estimation with teeth is the most significant method comparing ones with other part of the body. Gustafson method and Johanson method using postmortem teeth have been authorized in accuracy and systemization and used domestically and internationally. The verification of the accuracy in above methods had been tried many times but it is still rare in Korea. Fifty-nine teeth(incisors, canine, premolars and molars) which were extracted due to periodontal diseases or orthodontic problem were collected. Present study is to 1) compare the accuracy of estimated age in applying Gustafson method and Johanson method to the teeth in Korea, 2) compare and analyze the correlation with results using Gustafson method and Johanson method by age, gender, maxilla - mandible and anterior - premolar - molar. Teeth were embedded in resin and sliced and then examined each one using Gustafson method and Johanson method. The results are as follows: 1. Actual age was a significant difference in estimated age by Johanson method. Actual age was a significant correlation in estimated age by Gustafson method and modified Johanson method. Modified Johanson method was more significant than Gustafson method. 2. In estimated age by Gustafson method, Johanson method and modified Johanson method, there was no significance with actual age by location and gender. 3. In estimated age by Gustafson method, Johanson method and modified Johanson method, there was significance with actual age by age group. Finally, Gustafson method and Johanson method can be used in Korea. To make more accurate verification, however, it needs more specimen and postmortem teeth. Johanson equation proposed by himself has to be developed by further studies.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.215-230
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• 2005

The study was intended to investigate how dentists in private dental clinic thought on the present claim and review of dental insurance to reflect it in future establishing dental insurance policies. 1,465 dentists who were running own dental clinic in Pusan Metropolitan City and the south part of Kyungsang province were surveyed in February, 2004. A total of 406 copies of finished questionnaire were finally retrieved and analyzed. The findings are as follows. 1. About insurance claim affairs : Most of the subject of insurance claim was by dentist himself or dental hygienist(nurse). Agency claiming was carried under 20% of total insurance claim. 2. The degree of attendance on insurance lecture : The degree of attendance on insurance lecture was relatively low. 3. Filing a protest against insurance claim : Filing a protest against insurance claim was reavealed about half-and-half for "have been" or "have not been". 4. Private clinic dentist,s opinion about the regulations affecting review of dental insurance : Private clinic dentists opinion about current guide for insurance review of dental fee was“the guidance is difficult and unfair cutback of claim fee may be carried”. 5. The affairs about health insurance review agency : About 70% of private clinic dentists have dissatisfaction on health insurance review agency. 6. Standpoint of private clinic dentists about issuance of receipt for dental fee : About 70% of private clinic dentist have an difficulty in issuance of receipt for dental fee. 7. The affairs about change insurance noncoverage treatment to insurance coverage treatment : Most of private clinic dentists hoped that insurance coverage about full mouth scaling, pit and fissure sealant, fluoride application. But they do not hoped that insurance coverage about geriatric denture, prothodontic treatment except precious metal, photopolymerization resin treatment.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.247-255
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• 2005

The purpose of this study is to evaluate the effect of botulinum toxin type A on masseter muscle atrophy and the extent of masseter muscle affected from the injection site in relation to injection dose, with and without occlusal splint therapy through computed tomographic measurement. 32 volunteers were divided into four groups - group 25U (injection dose of 25 unit), group 25Us (injection dose of 25 unit with occlusal splint), group 35U (injection dose of 35 unit), group 35Us (injection dose of 35 unit with occlusal splint). Each group consisted of 8 people. 3 positions (position 1, 2, 3 - 10mm, 20mm and 40mm from the inferior border of the mandible, respectively) were selected for the evaluation of the masseter muscle change. The following results were obtained. 1. The thickness and the cross-sectional area of the masseter muscle had reduced in all groups except for the right side thickness at position 3 of group 25U and group 25Us, and the right side thickness as well as the left side cross-sectional area at position 3 of group 35Us. In group 35Us, the thickness and the cross-sectional area of the masseter muscle had reduced significantly in all positions (P < 0.05). 2. There was no significant difference in the masseter muscle change between the injection dose of 25unit and that of 35unit. 3. The groups with occlusal splint showed greater reduction of the masseter muscle thickness than the other groups (P < 0.05). From the above results, botulinum toxin type A injection together with occlusal splint therapy in the treatment of masseter muscle hypertrophy would be clinically effective.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.269-276
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• 2005

This in vitro study evaluated the influence of a flowable composite resin on the tensile bond strength of resin to enamel and dentin treated with Er:YAG laser and diamond bur. 96 Buccal enamel and mid-coronal dentin were laser-irradiated using an Er:YAG laser and treated with diamond bur. Each groups(48) were divided two small groups depends on acid-etching procedure. Light-cure flowable resin(Metafil Flo) and self-cure resin(Clearfil FII New Bond) were used in this study. After surface etching with 37% phosphoric acid and the application of an adhesive system, specimens were prepared with a hybrid composite resin. After 24hours storage in distilled water at 37$^{\circ}C$, all samples were submitted to the tensile bond strength evaluation, using a universal testing machine(Z020, Zwick, Germany). The obtained results were as follows: 1. TBS of acid-etching group were higher than those of non-etching group in both enamel and dentin treated with Er:YAG laser and diamond bur. Laser 'conditioning' was clearly less effective than acid-etching. Moreover, acid etching lased enamel and dentin significantly improved the microTBS of M-Flo. 2. In enamel, TBS of laser-irradiated group were lower than those of bur-prepared group. However, in flowable resin subgroup, there were not differed those between two groups in dentin. 3. In laser-treated group, TBS of flowable composite resin were higher than those of self-curing resin in dentin, however, there was no difference in enamel. From this study, we can conclude that the self- and light-cure composite resin bonded significantly less effective to lased than to bur-cut enamel and dentin, and that acid-etch procedure remains mandatory even after laser ablation. We suggest that Er:YAG laser was useful for preparing dentin cavity with flowable resin filling.

• Journal of Oral Medicine and Pain
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• v.31 no.1
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• pp.79-89
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• 2006

The aim of this study is to know how the rat submandibular gland changes under various emotional stress condition, using molecular biological methods. Restraint and chronic unpredictable mild stress (CUMS) experiment is conducted on fifty one 7-week old Sprague-Dawley rats (restraint stress experiment: 21, CUMS: 30). The rats were sacrificed, the submandibular glands were excised immediately at certain time, and examined by the use of immunohistochemistry and western blotting. In CUMS experiment, sucrose preference test, water intake change, weight change were implemented at 1 week interval for the experimental period The results are as follows: 1. The number of clusterin-secreting cells of restraint stress group compared to control group showed significantly decreasing tendency in all experimental groups except for the 1st hour group (p<0.001 in the 9th, 24th, 72nd, 120th, and 168th hour group). 2. The number of clusterin-secreting cells of CUMS group compared to control group showed significantly increasing tendency in the 2nd week group (p<0.01), and significantly decreasing tendency in the 4th and 5th week group (p<0.001). 3. Sucrose preference test in CUMS experiment showed significant difference between the 5th week experimental group and control group (p<0.01). 4. Weight change in CUMS experiment showed significant difference between the 5th week experimental group and control group (p<0.01), but water intake change didn't show significant difference compared to control group. 5. In western blot analysis, clusterin expression was decreased on a gradual basis in due time compared to the control group in the restraint stress group. As for CUMS group (chronic unpredictable mild stress group), it was increased till the 2nd week and decreased till the 5th week after that, which is similar to immunohistochemical analysis result and the decreasing tendency of sucrose preference and weigh changes. Through the test, it was proved that expression of clusterin in saliva glands decreases after receiving either acute or chronic stress, indicating relation with depression caused by chronic stress. Unlike other data, however, apoptotic tendency was hardly found in tissues. Diverse possibilities could be suggested on that: first, the stress was not enough to expedite apoptosis; second, apoptosis-related protein was already being secreted though not detected with microscope; third, clusterin, a major secretion molecule of saliva, decreased with saliva's malfunction due to stress. In the respect, it will be necessary to examine proteins expressed in case of cell death or other heat-shock proteins at the same time, in order to see whether any cellular change or death is caused by decreasing clusterin under high stress, and whether the original state is restored as time goes by under mild stress, through longer-term tests using even higher acute stress.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.297-316
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• 2006

The increasing tendency of medical disputes is one of the remarkable social phenomena. Especially we must not overlook the phenomenon that production and circulation of information related to medical accidents is increasing rapidly through the internet. In this research, we evaluated the web sites which provide the information related to medical accidents using the keyword "medical accidents" in March 2006, and classified the 28 web sites according to the kinds of establishers. We also analyzed the contents of the sites, and checked and compared the current status of the web sites and problems that have to be improved. Finally, we suggested the possible solutions to prevent medical accidents. The detailed results were listed below. 1. Medical practitioners, general public, and lawyers were all familiar with and prefer the term "medical accidents" mainly. 2. In the number of sites searched by the keyword "medical accidents", lawyer had the most sites and medical practitioners had the least ones. 3. Many sites by general public and lawyers had their own medical record analysts but there was little professional analysts for dentistry. 4. General public were more interested in the prevention of medical accidents but the lawyers were more interested in the process after medical accidents. The sites by medical practitioners dealt with the least remedies of medical accidents, compared with other sites. 5. General public wanted the third party such as government intervention into the disputes including the medical dispute arbitration law or/and the establishment of independent medical dispute judgment institution. 6. In the comparison among the establishers of web sites, medical practitioners dealt with the least examples of medical accidents. 7. The suggestion of cases in counseling articles related to dental accidents were considered less importantly than the reality. 8. Whereas there were many articles about domestic cases related to the bloody dental treatment, in the open counseling articles the number of dental treatment regarding to non insurance treatment was large. 9. In comparing offered information of medical accidents based on the establishers, general public offered vocabularies, lawyers offered related laws and medical practitioners offered medical knowledge relatively. 10. They all cited the news pressed by the media to offer the current status of domestic medical accidents. Especially among the web sites by general public, NGOs provided the plentiful statistical data related to medical accidents. 11. The web sites that collect the medical accidents were only two. As a result of our research, we found out that, in the flood of information, medical disputes can be occurred by the wrong information from third party, and the medical practitioners have the most passive attitudes on the medical accidents. Thus, it is crucial to have the mutual interchange and exchange of information between lawyer, patients and medical practitioners, so that based on clear mutual comprehension we can solve the accidents and disputes more positively and actively.

• Journal of Oral Medicine and Pain
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• v.32 no.1
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• pp.9-33
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• 2007

In the field of dentistry, there existed relatively few emergency patients or patients who need intensive care and thus had low medical dispute rates. However, these days, there is a general tendency of increased medical disputes. Although many medical disputes are caused by medical accidents of the dentists, because dental assistants are also lawfully involved in practicing dentistry, there is a possibility of medical disputes or medical accidents caused by dental assistants. Therefore, the role of the dental assistants cannot be ignored. This study consists of a survey given to dental hygienists currently working in general hospitals, dental hospitals and private dental clinics. Following is the results of the analysis of 275 respondents' backgrounds, medical disputes rates including patients' complaints, their understanding of medical regulations and their general understanding of overall dental practice and medical disputes. 1. 251 of 274(91.6%) respondents doubted the risk of medical accident and dispute. 2. 81(29.5%) dental hygienist experienced complaint from patients. They have been working in the private dental clinic, the rate of this experience was high. 3. 349 case of 1805(19.3%) the complaints by patients, highest percentage among its category, were those regarding dental fees and poor service. 4. 129 case of 1805(7.1%) patients' complaints, highest percentage among it's subcategory, were those regarding the absence of explanations of precautions or request of agreements before dental treatment. 5. 252 of 267 (94.4%) dental hygienists chart after a scaling treatment. However, only 55(20.7%) dental hygienists chart the fact of explaining the precautions. 6. 6(2.2%) dental hygienists do not inspect patients' medical history, if patients don't mention it. 7. 104 of 274(38.0%) dental hygienists responded to be capable of administering first aid treatment. 8. 115(41.8%) dental hygienists have a first aid kit and equipment. 9. In case of medical dispute, 268(97.8%) dental hygienists respond that, charting plays a big role in resolving the dispute. 10. In case of medical dispute, 272(93.3%) dental hygienists respond that, explanation and agreement before treatment have an important role in settlement of dispute 11. Only 160(58.4%) dental hygienists responded correct answer that the duration of keeping medical records is 10 years. 12. 124(45.3%) respondents thought that it is legal for a dental hygienist to take a panoramic dental X-ray, 71(25.9%) respondents thought that it is legal practice cervical resin treatment by dental hygienist, and 37(13.5%) respondents thought that it is legal extract primary teeth by dental hygienist. 13. 24(18.76%) respondents thought that it doesn't matter to tell patient's state to others 14. 272(99.27%) responded that receiving education for the prevention of medical disputes was needed and of them, 61.0% thought it was urgent. 15. 186(64.2%) has never had classes regarding the prevention of medical disputes while in school and 212(77.4%) has not had the same type of classes after graduating from school. 16. 256(93.4%) responded that there will be even more of an increased number of medical disputes. Among them, 83.3% of respondents though that due to the increased opportunity of acquiring information through the internet and mass media. The study shows that 29.5 percentage of dental hygienists have experienced the medical disputes and complaints and they are lack of recognition of medical regulations and dental hygienist's official duty. So, there is a big potential of the percentage to increase. Therefore, the correct understanding of explaining precautions and requesting agreement before dental treatments and performing them are mandatory. Moreover, classes regarding the prevention and counterplans of medical disputes need to be widely offered.