• Restorative Dentistry and Endodontics
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• v.29 no.4
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• pp.365-369
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• 2004

The purpose of this study was to evaluate the apical sealing ability of Super-EBA, MTA and Dyract-flow as retrofilling materials. Forty-eight extracted human teeth with straight and single root canal were used in this study. The root canals were prepared to a #40 apical canal size and obturated with gutter-percha. Apicoectomies were performed and root end cavities were prepared to a depth of 3mm using an ultrasonic device. The root end cavities were filled with Super-EBA, MTA or Dyract-flow. Leakage was measured using an electrochemical technique for 4 weeks. According to this study, the results were as follows. 1. Increasing leakage with time was observed in all groups. 2. No significant difference was noted among the 3 groups with time (p =0.216). 3. No significant difference was noted among the 3 groups when measured within the same time interval (p =0.814). The results of this study suggest that the sealing ability of Dyract-flow is equal to that of Super-EBA and MTA, and Dyract-flow may be an alternative to other materials for root-end filling.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.603-613
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• 2011

Objectives : This study is to investigate factors that predispose the oral health education patterns of teachers at preschool institutions such as kindergartens and day nurseries, for which a comparison was made among the patterns, whereto the PRECEDE model was applied. Methods : A survey was conducted by two visits, a preliminary survey and a main survey, and teachers at the foregoing institutions personally filled in the questionnaire. Results : 1. With relation to epidemiological and social diagnosis, the largest number of respondents (53.7%) agreed on the need for oral health education, but at the same time, the largest number of respondents (40.3%) was unsatisfactory with oral health education given by them. 2. With relation to behavioral diagnosis, there were many cases where respondents taught their students to brush their teeth after meals and snacks. Oral health education was focused on safety and injuries. There was no significant intergroup difference (p>0.05). 3. Predisposing factors (a subcategory of educational diagnosis) showed the following results: As for the frequency of oral health education, most respondents at both institutions answered preferred once every six month (p>0.05). In the case of oral health checkup, 75.4% of respondents at kindergartens preferred once a year. 72.2% of respondents at day nurseries preferred the same frequency. They showed a statistically significant difference (p<0.05). In enabling factors, it was found that most respondents at both institutions collected information and teaching materials from mass media and public health centers respectively. In enabling factors, insufficient teaching materials, media and knowledge were found to be obstacles to oral health education. Conclusions : Oral healthcare providers' cooperation is required to diversify away from tooth brushing-centered education and to enrich oral health education. In addition, continuous supplements are required to make teachers at preschool institutions acquire expert knowledge and give oral health education with confidence. Moreover, it needs to train them for various education programs as well as to support them with educational media. Lastly, family members' cooperation is required to develop oral health education programs.

• Journal of Korean society of Dental Hygiene
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• v.18 no.5
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• pp.653-664
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• 2018

Objectives: The purpose of this study was to examine the association between two major oral diseases and cardiovascular diseases. Methods: Data from the 6th Korean National Health and Nutrition Examination Survey (2013-2015) were used. The study included 12,754 adults, aged ${\geq}19years$, who participated in the questionnaire survey of health related to hypertension, stroke, myocardial infarction, and angina pectoris as well as completed blood tests, anthropometry, and oral examination. Statistical analyses included complex sample frequency, complex sample general linear, complex sample cross-tabulation, and complex sample logistic regression analyses. Results: With respect to the number of Decayed-Missing-Filled-Teeth(DMFT ), patients with hypertension (DMFT 8.05), stroke (DMFT 8.66), and angina pectoris (DMFT 8.24) showed a DMFT score of >2, compared with those who did not have these diseases (p<0.05). Patients with hypertension, stroke, myocardial infarction, and angina pectoris presented an approximately 2.7, 3.5, 4, and 3 times higher incidence of periodontal diseases, respectively, than those who did not (p<0.05). Based on the analysis of the relationship between the number of DMFT and cardiovascular diseases, patients with cardiovascular diseases had a risk of 1.033 higher DMFT than those who did not (p<0.05). As per the analysis of the relationship between periodontal diseases and cardiovascular diseases, patients with cardiovascular diseases had a 2.969 higher risk of periodontaldiseasesthanthosewithout them (p<0.05). Conclusions: Two major oral diseases were found to be associated with cardiovascular diseases. Therefore, to prevent these major oral diseases in patients with cardiovascular diseases, oral hygiene management must be actively performed.

• Journal of Korean society of Dental Hygiene
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• v.14 no.6
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• pp.881-886
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• 2014

Objectives: The purpose of the study was to investigate the related factors to dental fear in some adults. Methods: A self-reported questionnaire was filled out by 320 adults in Seoul and Gyeonggi-do from April to June, 2013. Except 14 incomplete answers, data were analyzed by SPSS 18.0 program. The questionnaire consisted of general characteristics of the subjects(7 questions), dental fear related factor(18 questions), distrust for dentist(15 questions), and distrust for dental hygienist(11 questions). The instrument for dental treatment fear was Dental fear Survey(DFS) adapted from Kleinknecht and partly modified by Choi. Out of 20 questions, 18 questions were reconstructed and score by Likert 5 scale. Higher score means higher dental fear. Cronbach alpha was 0.959 in the study. The distrust for dentist and dental hygienist was adapted from Choi and reconstructed and score by Likert 5 scale. Higher score means higher distrust for dentist and dental hygienist. Cronbach alpha was 0.937 in distrust for dentist and 0.874 in distrust for dental hygienist in the study. Results: Those who experienced dental pain tended to have dental fear. The reasons for dental fear were as follows; bad breath(2.96 out of 5 points, hereafter represented as of 2.96/5), dental caries(2.88/5), missing teeth(2.87/5) and tooth pain(2.77/5). The distrust for the dentist was the main dental fear in the adults. Conclusions: The dental fear was closely related to gender, experience of dental pain, oral symptoms and distrust for the dentist. As the psychological pain in the patients was mainly influenced by the trustful atmosphere, it is necessary to make the patient easy before treatment.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.72-79
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• 2003

The objective of this in vitro study was to evaluate the efficacy of a Ca(OH)$_2$removal before and after early coronal flaring using different types of instruments. 100 plastic blocks with 30$^{\circ}$artificial curved canals were used in this study and randomly divided into a control group and 4 experimental groups(GG, OS, GT, PT Group) 20 teeth each. The canals were instrumented, and Ca(OH)$_2$was temporary filled into the each canal. Irrigation was peformed with Max-i-Probe 25- 30-gauge probes before and after recapitulation. The results of this study were as follows 1. There were no significant difference among the groups in size of irrigating needle(p<0.05). 2. There was a significant difference between before and after recapitulation regardless size of irrigating needle(p<0.05). 3. Before recapitulation, there was a significant difference between 25- and 30-gauge needle in all groups(P<0.05). 4. After recapitulation, there was a significant difference between 25- and 30-gauge needle in the control group(p<0.05). But there were no significant difference among the experimental groups. It is concluded that the effectiveness of canal irrigation was decided to the depth of irrigating needle into the canal. The effect of canal irrigation tend to facilitate by the early coronal flaring. The recapitulation was the most effective during canal irrigation regardless the size of irrigating needle. Therefore, the recapitulation is a mandatory way to facilitate the effectiveness of canal irrigation during canal enlargement.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.447-463
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• 1997

The purpose of this study was to evaluate the effectiveness of copal varnish and five bonding agents(Scotchbond Multi-Purpose Plus Dental Adhesive System, Panavia 21, All Bond 2, Superbond D-Liner II plus, Fuji Duet) in reducing microleakage under amalgam restorations. Class V cavity were prepared on both buccal and lingual surface of sixty extracted human molars with cementum margin and were filled with different kinds of liners and amalgam. All teeth were stored at $37^{\circ}C$ in physiologic saline solution. After 1 week they were thermally stressed for 500 cycles between 5 and $55^{\circ}C$ in baths containing 0.5 % basic fuchsin dye. The dye penetrations were observed with a stereomicroscope. Scanning electron micrographs were taken of representative tooth sections from each group to assess the nature of the tooth/liner/amalgam interface. The statistical test were applied to the results using a one way analysis variance (ANOVA) and Duncan's multiple range test. The results were as follows ; 1. In all groups, the enamel margin showed significantly lower leakage value than the cementum margin (p<0.05). 2. At the dentin and enamel margins, the leakage value of Copalite-lined group showed significantly higher than that of no liner group (p<0.05), but showed significantly lower than that of bonding agent lined-groups (p<0.05). 3. There was no significant difference between the bonding agent lined-groups (p>0.05). 4. On the backscattered scanning electron microscopy observation, discontinuous gaps were observed between amalgam and dentin in the bonding agent-lined amalgam restorations and the bonding agents appeared to fill the gap space and were mixed with amalgam particles. At the amalgam/tooth interface, unsealed dentin and continuous gaps were found in both unlined and Copalite-lined restorations.

• Journal of Korean society of Dental Hygiene
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• v.20 no.4
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• pp.435-445
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• 2020

Objectives: This study investigated the relationship between obesity and dental caries of Korean adolescents. Methods: Data from the Korea National Health and Nutrition Examination Survey (KNHNES VI) (2013 to 2015) were used and targeted adolescents aged 13 to 18 years. For statistical analysis, the SPSS 18.0 program was used, and the significance level was set at 0.05. Results: For the general and health-related characteristics, female students (p=0.001) showed higher decayed, missing, and filled teeth (DMFT) index than male students. Furthermore, DMFT showed higher tendency, as age was higher (p<0.001). Smoking (p=0.011) and drinking experience (p=0.027) revealed higher DMFT. The dental caries experience was significantly different among students who were female (p=0.033), older (p=0.001), and overweight or underweight (p=0.022). In the BMI for the general and health-related characteristics, male students had higher obesity rate than female students (p=0.003), and obese subjects had higher dental checkup in the last year (p=0.013). In multiple linear regression analysis of obesity and DMFT, the unadjusted model showed that the obesity group's DMFT was about 0.8 higher than that of the normal group (p=0.024). However, statistical significance was not shown in the adjusted models. In the logistic regression analysis of obesity and dental caries experience, the unadjusted model 1 (1.93 times), the adjusted model 2 (1.79 times), and model 3 (1.76 times) showed significantly higher dental caries experience. Conclusions: Both obesity and dental caries are related to diet habits and lifestyles and have a negative impact on adult health. Therefore, it is necessary to create a healthy social environment around the adolescent, and proper intervention through education is required to form healthy habits.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.161-166
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• 1982

The purpose of this study was to examine the influence of canal preparation on the property of apical seal. Seventy canals from extracted human maxillary and mandibular teeth were randomly selected and divided into two groups: conventional group and step-back group. Thirty five canals in one group were enlarged with a, conventional preparation method and thirty five canals in the other group were instrumented in a step-back method with K-file. After instrumentation sixty canals were obturated by lateral condensation of gutta percha and zinc oxide eugenol cement, and five canals in each group were not filled and used as control. All the specimens were immersed in 2% methylene blue dye solution and the depth of dye penetration into the canals were observed by macroscope at the intervals of 1 day, 2 days, and 7 days. The following results were obtained. 1. All the canals experimented showed varying degrees of dye penetration. 2. There was no significant difference between conventional method and step-back method in the depth of dye penetration and the degree of dye penetration tended to increase with time passage in both groups. 3, In conventional preparation group the mean dye penetration was 3.6mm at 1 day, 4.8mm at 2 days. and 6.5mm at 7 days. 4. In step-back prepareation group, the specimens exposed to the dye for 1 day showed mean dye penetration of 4.1mm, and the specimens immersed in the dye for 2 days and 7 days revealed mean dye penetration of 4.6mm and 6.2mm respectively.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.69-76
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• 1982

The purpose of this study was to evaluate the color penetration of cavity margin with composite resin restorations in some Korean foods substance-soy sauce and hot bean paste. Fifty specimans which were extracted caries free third molar of young adults recently. All of the prepared 100 cavities were filled with two kinds of composite resin (Hipol$^{(R)}$and Restodent$^{(R)}$). The experimental specimans were divided into five groups by the following procedures. Group I : Filling of composite resin and polishing. Group II : Filling, polishing, etching of cavity and sealing. Group III : Etching, sealing, filling and polishing. Group IV : Etching, sealing, filling, polishing, and repeated of etching of cavity margin and sealing. Group V : Etching, sealing, filling, polishing, and sealing again without etching. Before examination, the restorated teeth were subjected to thermal cycling ($4^{\circ}C$ and $60^{\circ}C$). All the specimens were immersed in soy and 30% hot bean paste solution under $37^{\circ}C$ incubator during six weeks. Then, the specimens were sectioned bucco-lingually through the center of two restorations with diamond disk and examined under a. metallographic microscope. (Union 6617 U.S.A.) Thereafter, the degree of color penetration was calculated and analyzed. The obtained results were as follows: 1. The color penetration was the lowest in the procedure of Group III which was acid etching, sealing, composite resing filling, and polishing. 2. The color penetration occured in soy and hot bean paste, but the degree of penetration was not so significant statistically between them. 3. The degree of color penetration was not so significant statistically between Hipol$^{(R)}$ and Restondent$^{(R)}$.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.123-130
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• 2018

In the root fracture, pulp necrosis tends to involve only the coronal fragment, while the pulp in the apical fragment remains vital. The prognosis of endodontic treatment of the apical fragment is poor due to the possibility of overfilling of the space between the fragments and difficulty in removing necrotic tissue. In the present cases, endodontic treatment of the apical fragment of root fracture was performed. However, in reendodontic treatment, resistance was felt at the fracture site and access to the root canal in the apical fragment was difficult. Therefore, the calcium hydroxide was periodically exchanged only in the coronal fragment without further treatment in the apical fragment and the canal of the coronal fragment was finally filled with Gutta-percha. Regular observation revealed no radiologic complications in the apical fragment. In some cases, we can observe good healing pattern such as absorption of calcium hydroxide and pulp canal obliteration of apical fragment in the long term.