• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.99-107
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• 2009

Statement of problem: Restoring and replacing teeth with fixed prostheses commonly used in dental practice. Because of improper oral hygiene care and inaccurate laboratory procedure, complications of fixed prostheses were found in the mouth of patients. Although many efforts have been continually made to obtain the data of long term prognosis of fixed prostheses, it was difficult to do it. Purpose: The purpose of this study was to evaluate the clinical status of fixed prostheses. Material and methods: In order to assess the clinical status of fixed prostheses, a total of 161 individuals(aged 17-85, 99 women and 62 men with 1596 unit of fixed prostheses, and 1169 abutments) who first visited the Department of Prosthodontics, Pusan National University Hospital, between April to September, in 2007 were examined. Results and conclusion: The results of this study were as follows: 1. Length of service of fixed prostheses was $8.6{\pm}0.6$ years(mean), 10.0 years(median). 2. Location of fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses(P>.05). But, the success rate was high in posterior region and in mandible where the failure rate was high in combination(P<.05). 3. Longevity of fixed prostheses made of metal was longest(mean: $13.0{\pm}9.3$, median: 14.0), gold, precious ceramic, non-precious ceramic trailing behind(P<.05). 4. Number of units in fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses(P>.05). But, the success rate was high in Single-unit and the failure rate was high in over 3-unit(P<.05). 5. Condition of opposing dentition was found to have no statistically significant influence on longevity of fixed prostheses(P>.05). But, the success rate was high in natural dentition(P<.05). 6. Defective margin(28.2%), dental caries(23.0%), periodontal disease(19.3%), periapical disease(16.9%) were frequent complications. In 30.1% of the cases, abutment state after removing fixed prostheses was needed to be extracted.

• Journal of dental hygiene science
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• v.2 no.1
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• pp.39-45
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• 2002

Our study shows the following results of the patterns and reality of oral health of 862 Government employees and private school employees who had received oral examinations from April to May, 2000. For the exposition of each group to dental service, the male groups(37.4%) were more exposed than the female ones(30.0%, p<0.05), while the scaling experience results indicated that more ages mean more scaling(the over 50 year group 27.1%, 41-50 group 23.9%, 31-40 group 20.5%, 21-30 group 10.8%, p<0.001). The data involving sweet food and refreshments revealed that 'positive respondents' in the male groups were 19.7% with 12.5% positive in the female ones, and 'negative respondents' were 32.3% and 51.0% in the male and female groups respectively(p<0.001). For the oral odor, the male groups(37.9%) are more severe than the female ones(25.5%, p<0.01). The results of dental caries revealed that 19.1% of the male and 13.9% of the female said 'yes'(p<0.05), with 25.1% of the male and 11.1% of the female suffering from missing teeth(p<0.001); 77.4% of the male and 51.0% of the female from periodontal disease (p<0.001).

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.421-430
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• 1997

Alveolar bone grows with development of tooth germs and roots; bone deposition occurs with tooth eruption. Bone components undergoes processes of resorption and deposition, and when the balance between them is disrupted, decrease in alveolar bone height or excessive bone deposition result. It has been hon that repositioning of teeth through orthodontic treatment can cause alveolar bone resorption which result in decreased alveolar bone height, and there have been many studies to evaluate such effects. X-ray films that could be replicated and standardized were chosen in clinical studies, and among them, bitewing films were used for objective evaluation of changes in alveolar bone level. Twenty subjects, 10 to 13-year- old (average 12.2) children with Cl I molar key, healthy oral condition, no congenital missing, no periodontal disease, and pre-and post-orthodontic bitewing films, were randomly selected for comparison of alveolar bone heights. Amounts of tooth and changes in alveolar bone heights were analyzed. The following results were obtained: 1. Amount of tooth movement in canine, premolar, and molar regions, changes in tooth axis, and changes in alveolar bone heights were measured, and the mean and median values were obtained. 2. When pre-and post-orthodontic alveolar bone levels were compared, larger changes were noticed in maxilla than mandible. 3. When mesio-distally compared, larger changes were observed in the distal sides of 3D3 and 4M3, mesial sides of 4M3 and 4D3, distal sides of 4D3 and 5M3, mesial sides of 5M3 and 5D3, md distal sides of 5D3 and 6M3. 4. When the amounts of tooth movements(TX, TY)and changes in tooth axis(A) were compared,34TX, 34TY, 34A of both sides in maxilla were greater, iud changes in alveolar bone level were greater than any other region.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.1
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• pp.45-58
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• 2013

The purpose of this study was to analyze the area of occlusal contact points using visual method. One subject was selected who had Angle Class I, normal dentition, without dental caries, periodontal disease and temporomandibular disorders. Forty times PVS impressions were taken and 10 pairs casts were fabricated using dental super hard stone. After mounting the casts with customized loading apparatus, 78.9kg/f force was loaded as a maximum biting force. In T-Scan method, occlusal contact points measurement was repeated twice. Then, using Photoshop program (Adobe photoshop CS3, Adobe. San Jose, USA), the pixels which indicated occlusal contact points by color was recognized, and the distribution of recognized pixels were calculated to area. In Add picture method, polyether bite material applied to the occlusal surface of the casts. Then, the image of the translucent areas was recorded and classified $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area by the amount of transmitted light. To acquire occlusal surface, the numbers of pixels from the photograph of the contact area indicated cast converted to $mm^2$. The mean occlusal contact area by two methods was statistically analyzed (paired t-test). Part of the red and pink area in T-Scan image were almost equivalent to the $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area in Add picture image. The distribution of occlusal contact points were similar, but the average area of occlusal contact points was wider in T-scan image (P<.05). Pink and red area in T-scan image was wider than $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$ area in Add picture image (P<.05), but similar to $0{\sim}60{\mu}m$area in Add picture image (P>.05). Occlusal contact points in T-scan image did not indicate real occlusal contact points. Occlusal contact areas in T-scan method were enlarged results comparing with those in Add picture method.

• Journal of Oral Medicine and Pain
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• v.33 no.2
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• pp.159-166
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• 2008

An ideal anti-bacterial medication for oral infection requires selective effect on pathogens causing dental caries and periodontal disease but not on normal flora. In addition, it should be less toxic for human and even for environment. This study was to seek such a natural anti-bacterial medication and thus anti-bacterial effect of Hamamelis virginiana was evaluated. Many recent researches on the anti-bacterial effect of natural plant extract and essential oil have reported that natural products can be used as medication for prevention and restrainment of dental caries, halitosis and periodontitis. It has been also reported that Hamamelis virginiana has anti-bacterial effect on Porphyromonas gingivalis, Fusobacterium nucleatum, Capnocytophaga gingivalis, Veilonella parvula, Eikenella corrodens, Peprostreptococcus micros, and Actinomyces odontolyticus. This study evaluated anti-bacterial effect of Hamamelis virginiana on Streptoccoccus mutans, Haemophylus actinomycetemcomitans, and Klebsiella pneumoniae to expand its anti-bacterial effect on other important oral pathogens and eventually to develop its oral care products or apply to clinical purpose. In this study, anti-bacterial tests for antibiotic disk susceptibility, minimal inhibitory concentration and minimal bactericidal concentration were performed to evaluate anti-bacterial effect of Hamamelis virginiana against Streptoccoccus mutans, Haemophylus actinomycetemcomitans, and Klebsiella pneumoniae. The results showed that Hamamelis virginiana has anti-bacterial effect on all pathogen strains tested in this study and furthermore Hamamelis virginiana possesses bactericidal effect other than bacteriostatic effect on Streptoccoccus mutans, Haemophylus actinomycetemcomitans, Klebsiella pneumoniae. This study indicates that a natural anti-bacterial medication for oral diseases can be developed using Hamamelis virginiana.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.245-250
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• 2005

This study was executed from June first to 30th. 2005. The target was first and second graders of Bok-Hyun elementary school and their mothers. The total of participants was 275 persons and the component ratio was 135 first graders and 140 second graders, also 82 boys and 193 girls. They answered to the question sheet by writing out with their own hands. Among the 300 question sheets that were answered, 275 sheets were analyzed, excepting 25 sheets that got poor answer. The results were as follows; (1) About the behavior of mothers and their children for oral health, In mothers' case, 68.8% of them answered that they brush teeth more than 3 times a day and 31.3% answered that they brush teeth less than 2 times a day, so those who brush teeth more than 3 times were more than those who brush teeth less than 2 times In children's case, on the contrary, 14.2% of them answered that they brush teeth more than 3 times a day and 85.8% answered that they brush teeth less than 2 times a day, so those who brush teeth less than 2 times were more. (2) In 7 questions for researching mothers' knowledge level about fluorine, 55.3% of them answer 3~4 questions correctly. In 7 questions for researching mothers' knowledge level about Periodontal disease, 47.3% of them answer 3~4 questions correctly and it was highest. (3) In a case of the relation between oral health knowledge and behavior of mother and frequency of brushing teeth of children, statistical similarity on frequency of brushing teeth was shown(p < 0.05). (4) In a case of the relation between social-anthropological features of mother and frequency of brushing teeth of children, there was no statistical similarity on age, mothers' educational level, monthly income. However, statistical similarity was shown about existence of mothers' occupation(p < 0.05).

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.375-381
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• 2007

Occlusal stabilization appliance is one of the most common treatment option for management of temporomandibular disorders. It acts in oral cavity for several hours per day, and usually it will take at least 6 months to 2 years of total wearing periods to take a treatment goal. In the oral cavity, occlusal stabilization appliance, unintentional manner, is able to acts as a reservoir of bacteria and protect bacteria from saliva and oxygen. This condition is so favorable to many bacteria such as S. mutans and other anaerobes, usually have been reported as causative factors of dental caries, periodontal disease and oral malodor. In this study, we investigated anaerobic bacteria and S. mutans count before and after occlusal stabilization appliance use to evaluate the possible role of occlusal stabilization appliance as protector of these bacteria. Four men(average 27.5 years) wore maxillary occlusal stabilization appliance at each night(average 9 hours) for 5 days. we swabbed saliva-plaque mixed sample at 3 different site(maxillary left 2nd molar, maxillary left central incisor, mandibular left 2nd molar) before and after occlusal stabilization appliance use. Each samples were plated in (1) anaerobic blood agar medium, (2) selective S. mutans medium(MS-MUTV) and incubated in anaerobic chamber($CO^2$ 10%, $37^{\circ}C$) for 72 hours. Each bacterial colony forming unit(CFU) were counted with naked eyes. From obtained data, we can conclude as follows: 1. There was some changes about anaerobic bacteria and S. mutans count in oral cavity after occlusal stabilization appliance use. 2. The number of anaerobic bacteria was significantly increased at maxillary 2nd molar(P=0.003), maxillary central incisor(P=0.020) after occlusal stabilization appliance use compared with before. 3. Occlusal stabilization appliance use itself had indirect effect to increase the number of anaerobic bacteria at other uncovered opponent tooth site. 4. The number of S. mutans was significantly increased at maxillary 2nd molar(P=0.043), maxillary central incisor (P=0.049) after occlusal stabilization appliance use compared with before. 5. Occlusal stabilization appliance use itself had not any effect on the number of S. mutans at other uncovered opponent tooth site.

• Journal of dental hygiene science
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• v.7 no.3
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• pp.121-127
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• 2007

The purpose of this study was to analyze college students basic knowledge of oral health of a college student and compare with the knowledge of oral health between dental hygiene students and non-dental hygiene students. A survey was conducted on the residents in Gyeonggi-do and Gwangju from June 2006 to May 2007. The findings of the study were as follows: 1. Concerning the knowledge of oral health, dental hygiene students got the source of information most frequently from school work about oral health(80.0%) and non-dental hygiene students got from health programs of TV or radio(42.7%). Concerning the reason of keeping of oral hygiene, dental hygiene students were to preventive of dental caries(80.9%) and nondental hygiene students were to preventive of periodontal disease(52.4%). There were significant difference between dental hygiene students and non-dental hygiene students(p < 0.001). 2. The knowledge degree of dental caries, to the both groups, methods of preventing caries appeared regular brush and main cause of dental caries was not to brush. There were significant difference between dental hygiene students and non-dental hygiene students(p < 0.001). 3. Dental hygiene students answered about the knowledge of fluoride know fluoride(93.6%) and non-dental hygiene students answered (55.3%). Dental hygiene students thought that fluoride could preventive dental caries(85.5%) but non-dental hygiene students thought that fluoride couldn't preventive dental caries(51.0%). There was significant difference between dental hygiene students and non-dental hygiene students(p < 0.001). 4. In the knowledge of oral health state, both of groups, replied that their own tooth state is average but they concerned about their tooth health. There was significant difference between dental hygiene students and non-dental hygiene students(p < 0.001). About main cause of dental caries, students ranked that the first reason was the poor toothbrush and the second reason was the over intaking of sugared foods. 5. About knowledge of oral diagnosis, to both groups, students ranked that first could endure the pain and the second was in much pain. For both groups, students ranked that difficult of dental treatment was cost, fear and time. There was significant difference between dental hygiene students and non-dental hygiene students(p < 0.01). For both groups, when they visit dentist's office, they felt misgivings and fear.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.317-326
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• 2013

This study was to compare the cumulative survival rate of implant-supported fixed prostheses and to analyze association between risk factors and cumulative survival rate of implant-supported fixed prostheses. In order to assess the clinical status of implant-supported fixed prostheses, individuals who treated in the Department of Prosthodontics, Pusan National University Dental Hospital, between 2000 to 2007 were examined. The results of this study were as follows: 1. Length of service of implant-supported fixed prostheses was $6.6{\pm}32.0$ years (mean), 11.7 years (median). 2. Age and sex of patient was found to have no statistically significant influence on longevity of implant-supported fixed prostheses (P>.05). 3. Reason of tooth extraction wax found to have statistically significant influence on implant-supported fixed prostheses (P<.05). The longevity of fixed prostheses was low in tooth extraction case due to periodontal disease (median:9.0 years). 4. Location of implant-supported fixed prostheses was found to have statistically significant influence on longevity of fixed prostheses (P<.05). The longevity of fixed prostheses was low in molar region (median:8.8 years). 5. Number of units in implant-supported fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 6. Condition of opposing dentition was found to have no statistically significant influence on longevity of implant-supported fixed prostheses (P>.05). 7. Food impaction (40.5%), porcelain fracture (25.8%), screw loosening (23.6%) were frequent complications.

• Journal of dental hygiene science
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• v.10 no.6
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• pp.473-479
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• 2010

This study purposed to survey D university students' perception of kindness in their use of dental care services in an area of Gyeonggido. For this purpose, we conducted a questionnaire survey of 502 students from October 2, 2008 to March 6, 2009 and analyzed the data. Results obtained from this study are as follows. 1. Of the subjects, 71.3% were female, 67.7% were at the age of 20 or younger, and 89.2% had experience in visiting a dental clinic. Among the subjects who had experience in visiting a dental clinic, 31.1% replied that they were highly interested in oral health, and to the question on the selfperceived current oral health condition, 35.1% replied that there was something wrong in their oral health condition. 2. With regard to correlation between general characteristics and interest in oral health, 79.9% of the male subjects and 83.2% of the female ones were highly interested in oral health. According to age, interest in oral health was highest among those aged 26 or older 92.0%. 3. With regard to correlation between general characteristics and oral health condition, if the presence of dental caries or periodontal disease was considered an indicator of poor oral health, 66.0% of the male subjects and 70.9% of the female ones appeared unhealthy, 72.0% of students aged 26 or older showed satisfaction. 4. The most frequent reason for not visiting a dental clinic was 'Not sick' 34.6%, and among those who had experience, the most frequent reason for visiting was 'To get treatment of sick teeth' 63.0%. With regard to the perceived kindness of dentist and dental hygienist, 40.6% and 45.8% of the subjects, respectively, were highly satisfied. The most frequent reason for satisfaction was 'Comfortable with patient reception' 34.4% and the most frequent reason for dissatisfaction was 'Explain treatment insufficiently' 30.7%. 5. As to perceived kindness according to gender, 60.9% of the male subjects and 56.1% of the female ones were satisfied with dentist's kindness, and 66.9% and 59.6%, respectively, were satisfied with dental hygienist's kindness. According to age, 62.5% of students aged 26 or older showed satisfaction with dentist's kindness and 78.3% of them with dental hygienist's kindness. 6. As to perceived kindness according to correlation between interest in oral health and current selfperceived oral condition, the kindness of dentists(68.0%) and hygienists(67.8%) was perceived higher when interest in oral health was high and not very interested and the kindness of dentists(50.0%) and hygienists(66.78%) when selfperceived oral condition was healthy, and the difference was statistically significant (p<.022 and p<.023, respectively).