• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.2
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• pp.75-84
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• 2001

The purpose of this study is to to analyze the mechanical stress on articular disk of the dentated skull with the condition of unilateral posterior molar missing. For this study, the three dimensional finite element model of human skull scanned by means of computed tomography. (G.E. 8800 Quick, USA) was constructed. The finite element model of jaws is composed of 98,394 elements and 38,321 nodes, and it consists of articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. Boundary condition included rigid restraints at the first molar and endosteal cortical surfaces of the insertion points of temporal bone. The data derived from Nelson's study were used for the loading conditions of mandible during clenchings and for maxilla, new loading and constraint conditions were applied. A clenching task during intercuspal position was modeled to the three dimensional finite element model. The stress level and displacement of articualr disc on the model with unilateral posterior molar missing under bilateral clenching task can be analyzed. During bilateral clenchings, the compressive stress level and diplacement of the articular disk on the side of unilateral posterior molar missing is greater than that on the case with full dentition, whereas a higher stress was found on the disk on the balancing side of the full dentition. Although this kind of study is not enough to explain the role of occlusion as an etiologic factor of TMD, there may be a possibiliy that the condition of posterior molar missings may contribute in part to the TMJ biomechanics.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.319-326
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• 2016

Recently multicultural female population is increasing of our country as international marriages increase. With oral care programs, conducting follow-up surveys on multicultural women's oral health condition to figure out the condition and examining improvements and related factors, it tried to contribute to building oral care programs for the future of multicultural families. The study participants were recruited from multi-cultural family center in a metropolis, they were treated their oral conditions at local dental clinics during a year. All participants were 608 people, and among them, one year follow-up sample was 40 women. An interview questionnaire was used to collect information on socioeconomic level and general characteristics related to oral status, through oral examination were conducted to obtain dental caries experience and periodontal conditions. The statistical analysis was done by using the SPSS 20.0 program. Comparing the results between before and after oral health program for an year, DMFS, DS, FS, DT, FT and CPI were significantly decreased during a year. The present study increases interest about multicultural women and family and we look forward to using it as basic data for oral health promotion.

• Journal of Korean society of Dental Hygiene
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• v.9 no.1
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• pp.125-139
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• 2009

Objective : This study was performed in order to provide basic data for halitosis prevention and establish a device to efficiently eliminate halitosis and to analyze the factors that affect the halitosis. Methods : Oral examination on the Gingival index, CPITN, Tongue Plaque index, and OHI-S as well as halitosis measurement among 293 rural residents. Results : Gingival index was high at mild on female and at moderate on male(p=0.025). Sorting the result by age, mild was 54.1% in the 40s, and moderate was 49.5%, 42.0% and 70.0% each in the 50s, 60s, and the 70s(p=0.005). The need for dental plaque management was 100%. The need for scaling was high with 78.3%, 93.0%, 89.9%, and 90.0% each for the 40s, 50s, 60s, and 70s. The need for complex periodontal treatment was also high with 32.4%, 47.5%, 48.7% and 60.0%, each for the 40s, 50s, 60s, and 70s(p=0.050). The highest bad condition for OHI-S was 69.5%, and good being 18.9%, and very bad being 11.6%. For moderate tongue plaque index was 74.4% as the highest. As the level of education increased, the slight tongue plague was increased, but in contrast, the moderate and higher tongue plague index was decreased(p=0.010). OG under 50ppm was 61.1% on male and OG over 50ppm was 50.9% on female(p=0.041). In OG over 50ppm, CPITN was 52.1% and 41.9% in scaling and complex periodontal treatment group(p=0.018). OHI-S, in bad and very bad condition with OG, over 50ppm, was 48.7% and 46.9%(p=0.019). The higher tongue plague index showed significant amount of increase at OG and EG above 50ppm(p=0.006). $NH_3$, as the tongue plaque index increased, the wider range of distribution was shown(p=0.000). As for the multiple regression analysis result, there have been selected females and tongue plaque index as factors affecting OG. There have been selected age and tongue plaque index as factors affecting EG and there have been selected females as factors affecting on $NH_3$. Conclusions : With the aforementioned results in mind, the status of halitosis among rural residents is considered to bare a close relation with oral environments. we have to focus on correct tooth brushing methods and tongue brushing, with using tongue cleaner to remove fur of tongue plaque. Also, in order to analyze exactly the factors of individual halitosis, we need continuous and systematic study.

• Journal of Korean society of Dental Hygiene
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• v.13 no.1
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• pp.89-97
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• 2013

Objectives : For investigating relationship between oral condition and body mass of adolescent period and helping to make basic data which make oral care systematically while performing health care for adolescent. Methods : This research was carried out by performing oral and physical test of 273 high school students in some reasons from July 2nd to 16th in 2012. Results : There were significant differences, since the more subjects had irregular occlusion, the more they had loosing tooth(p<0.05). There was a significant difference, since when subjects had more numbers of regular occlusion, they had higher BMI and heavier weight.(p<0.001). There are significant different, since when the subjects had worse peridontal condition, they had more numbers of DT(p<0.001). There was a significant difference in occlusion and body mass group, since when subjects had regular occlusion, 46.4% of subjects were standard body weight, 41.0% of subjects were overweight and when subjects needed orthodontics, 52.7% of subjects were standard body weight, 33.8% of subjects were low-weight, and 13.5% of subjects were overweight(p<0.001). In the correlation between oral condition and BMI, DT index showed negative interrelation with FT index(r=-0.179) and positive interrelation with periodontal condition(r=0.221), MT index showed positive interrelation with occlusion(r=0.137) and FT index showed positive interrelation with height(r=0.136). BMI showed highly positive interrelation with weight(r=0.940), and when occlusion was worse, it shows negative interrelation with BMI(r=-0.293). Height showed highly positive interrelation with weight(r=0.447), and when the more subjects had malocclusion, it showed low negative interrelation with weight (r=-0.257). Conclusions : It was considered that an adolescent period forms health habits, so it was important to increase health action through education for growing healthy adult and not only guiding improvement of dietary life for keeping normal weight, but also conducting oral health education for treating regular occlusion of oral condition and prosthetic procedures for loosing tooth right time.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.532-536
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• 2008

Purpose: This study was designed to evaluate effect of EMD on proliferation of HPDLCs and MC3T3-E1 cells in high glucose condition in vitro. Material and method: The Human PDL fibroblasts(HPDLCs) were obtained through typical way and the cells used in this experiment were divided in 4 groups. $1{\times}10^4/ml$ HPDLCs suspension was cultured in typical DMEM and assigned to group 1. The cells cultured in DMEM which included 400mg/dl glucose are allocated to group 3. Group 2 and 4 are established by adding EMD to group 1 and 3 respectively. These control and experimental groups had been cultured for 24 and 48 hours, and MTT assay was conducted. The differences of each group in cellular proliferation was evaluated. The same experiment was conducted for preosteoblast (MC3T3-E1) with adding $25\;{\mu}g/ml$ EMD. Results: EMD had the same effect on both PDL cells and MCT3T3-E1 cells. The experimental group had more meaningful differences and active cellular proliferation than the control group did. The EMD accelerated cellular proliferation not only in normal glucose condition but also in high glucose condition. The same results were observed via MTT assay; EMD-added experimental group had more meaningful differences and showed higher cellular activity than control group did. Each experimental and control group was inspected for statistical significance through Kruskal-Wallis Test. Statistical significances were observed among these groups. (SPSS 12.0 Chicago, IL, USA, p=0.008, p=0.011) Conclusion: EMD is considered to accelerate proliferation of PDL cells and MC3T3-E1 cells in high glucose condition as well as normal glucose condition.

• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.451-463
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• 2001

Following the extensive use of implant, the incidence of peri-implantitis increases. Guided bone regeneration has been used for the optimal treatment of this disease. Because implant surface was contaminated with plaque and calculus, cleaning and detoxification were needed for the reosseointegration when guided bone regeneration was performed. Various mechanical and chemical methods have been used for cleaning and detoxification of implant surface, air-powder abrasive and oversaturated citrate were known to be most effective among these methods. However, these methods were incomplete because these could not thoroughly remove bacteria of implant surface, moreover deformed implant surface. Recent studies for detoxification of the implant surface using laser were going on, $CO_2$ laser and Soft Diode laser were known to be effective among these methods. The purpose of this study was to obtain clinical guide by application these laser to implant surface. 15 experimental machined pure titanium cylinder models were fabricated. The $CO_2$ laser treatment under dry, wet and hydrogen peroxide condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of models. Each groups were examined with SPM and SEM to know whether their surface was changed. The results were as follows : 1. Surface roughness and surface form weren't changed when $CO_2$ laser was usedunder dry condition(P>0.05). 2. Surface roughness and surface form weren't changed when $CO_2$ laser was used under wet condition(P>0.05). 3. Surface roughness and surface form weren't changed when $CO_2$ laser was used under hydrogen peroxide condition(P>0.05). 4. Surface roughness and surface form weren't changed when Soft Diode laser was used under toluidine blue O solution condition(P>0.05). From the result of this study, it may be concluded that the $CO_2$ laser having relatively safe pulse mode and the Soft Diode laser used with photosensitizer can be used safely to treat peri-implantitis.

• Journal of Korean society of Dental Hygiene
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• v.12 no.2
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• pp.409-417
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• 2012

Objectives : The purpose of this study is to figure out and establish the basic data that can help improve management of oral healthcare for the international marriage immigrant women. Methods : In this sense, we surveyed questions on 237 women out of 1,300 immigrant women, who have participated in the program by multi-cultural household supporting center, in a fashion of face-to-face investigation and on-the-spot direct cavity inspection simultaneously from May 1 to October 31, 2010. Collected data were electro-statistically computerized under SPSS 17.0 program and analyzed with frequency analysis, recurrence analysis and logistic regression analysis respectively. Results : The number of filled teeth got lower when they had lower number of dental visits. Women from the Philippines had the highest number of defect teeth, and the number of fixed prosthetic appliance became less when they had less number of dental visits. When they had no experience of oral health education, they had less fixed prosthetic appliances. There was higher percentage of periodontal disease when they did not have dental visit compared with the dental visit cases. Conclusions : Preparation of a policy for east Asian immigrant women for them to visit dentist comfortably and expansion of systematic oral health education are highly recommended.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.2
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• pp.107-111
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• 2013

Careful examination of the oral cavity may reveal findings indicative of an underlying systemic condition, and allow for early diagnosis and treatment. Examination should include evaluation for mucosal changes, periodontal inflammation and bleeding, and general condition of the teeth. A 12-year-old man visited for molar pain during 3 months. He was diagnosed with having a possibility of hematopoietic malignancy, showing the loss of lamina dura, destruction of bony crypt, and high attenuation in the bone marrow. He was referred to department of pediatrics, additional study, including peripheral cell morphology and bone marrow exam, were performed, and diagnosed as acute lymphoblastic anemia. Despite chemotherapy to cure leukemia, he was expired 8 months after initial diagnosis. The purpose of this report is to promote and evoke the awareness regarding an initial examination of the dentist to make an effort to acquire accurate knowledge and information about life-threatening disease in usual dental practice.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.363-373
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• 1995

The aim of this study was to evaluate and compare observer performance between conventional radiographs and their digitized images for the detection of bone loss in the bifurcation of mandiblar first molar. One dried human mandible with minimal periodontal bone loss around the first molar was selected and serially enlarged 17 step defects were prepared in the bifurcation area. The mandible was radiographed with exposure time of 0.12, 0.20, 0.25, 0.32, 0.40, 0.64 seconds, after each successive step in the preperation and all radiographs were digitized with IBM-PC/32 bit-Dx compatible, video camera (VM-S8200, Hitachi Co., Japan), and color monitor(Multisync 3D, NEC, Japan). Sylvia Image Capture Board for the ADC(analog to digital converter) was used. The obtained results were as follows: 1. In the conventional radiographs, the mean score of the readability was higher at the condition of exposure time with 0.32 second. Also, as the size of artificial lesion was increased, the readability of radiographs was elevated (P<0.05). 2. In the digital images, the mean score of the readability was higher at the condition of exposure time with 0.40 second. Also, as the size of artificial lesion was increased, the readability of digital images was elevated(P<0.05). 3. At the same exposure time, the mean scores of readibility were mostly higher in the digitized images. As the exposure time was increased, the digital images were superior to radiographs in readability. 4. As the size of lesion was changed, the digital images were superior to radiographs in detecting small lesion. 5. The coefficient of variation of mean score has no significant difference between digital images and radiographs.

• Journal of Korean Dental Science
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• v.2 no.2
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• pp.24-30
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• 2009

Two component orthodontic C-implants have been introduced as intermaxillary fixation (IMF) screws in cases of periodontal problems with bone loss, severely damaged teeth, or short roots. This retrospective research sought to investigate the complications and risk factors associated with the failure of two-part C-implants for IMF cases and to show the possible indications compared to one-component mini-implants. The study sample consisted of 46 randomly selected patients who had a total of 203 implants. Pearson chi-square tests of independence were used to test for associations among categorical variables. At least 19 of the total 203 implants failed (9.3%). There was no significant difference in implant failure due to gender, oral hygiene, and placement, although a significant difference due to soft tissue characteristics and root contact was observed. The two-component design of the mini-implant is reliable for difficult IMF cases. Note, however, that the factors influencing implant failure were found to be age, root damage, and condition of soft tissues.