• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.44-56
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• 1990

This study was designed to assess the degree of the marginal leakage of posterior composite restorations with glass ionomer cement base and Scotchbond$^{(R)}$ by means of the dye penetration at the enamel and dentinal margins. 160 cavities of class V were prepared on the buccal and lingual surfaces of 80 extracted premolar and molar teeth, which were divided into two groups. The buccal cavities of one group were filled with GC lining cement$^{(R)}$, Scotchbond$^{(R)}$ and P 50$^{(R)}$ and the lingual cavities were filled with Scotchbond$^{(R)}$ and Heliomolar$^{(R)}$. The Buccal cavities of other group were filled with Logobond$^{(R)}$, Scotchbond$^{(R)}$ and Heliomolar$^{(R)}$ and lingual cavities were filled with Scotchbond$^{(R)}$ and P 50$^{(R)}$. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$ and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours and buccolingually sectioned with diamond disc. The sectioned specimens were examined under light microscope. The following results were obtained. 1. The group filled with glass ionomer cement base showed less marginal leakage than the group filled without glass ionomer cement base. 2. The enamel margins showed less microleakage than the dentinal margins in both of the two groups. 3. No significant difference was showed in the microleakage, irrespective of two glass ionomer cement base and posterior composite resin.

• Journal of agricultural medicine and community health
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• v.30 no.3
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• pp.263-277
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• 2005

Objectives: This study aimed to reveal the oral health conditions based on the dental health behaviors of a community-dwelling elderly. Methods: The subjects included 206 rural dwellers(100 men & 106 women) aged over 65 years old, who received dental health check-ups in the local public health center and its branches attached to 6 respective Myons of Chunchongnamdo Province, during the 2-month period from Jan. 1st to Feb. 28th, 2005. They were examined by dentists and given self-administered questionnaires asking about their dental heaith behaviors and subjective symptoms of gingival bleeding. Results: The oral health conditions based on dental health behavior showed that those who have not taken dental health service a year were found to have significantly greater number of missing teeth(p=0.002), DMFT(p=0.002) and CPITN(p=0.018), and those who have not observed intra-oral conditions a week to have significantly less number of filled teeth(p=0.002) and significantly greater number of missing teeth(p=0.000) and CPITN (p=0.000) than their respective counterparts. In terms of brushing, those who brushed their teeth below "3 times/day" were found to have significantly greater number of decayed teeth(p=0.000), missing teeth(p=0.000), DMFT(p=0.000) and CPITN(p=0.000) than their counterparts. In terms of time spent in brushing, those who spends "below 3 minutes" had significantly greater number of missing teeth(p=0.002) and DMFT(p=0.041), and significantly less number of filled teeth(p=0.036). According to the use of aid tools for cleaning teeth, the group who don't use them had significantly greater number of DMFT(p=0.041) and CPITN(p=0.018) than its counterpart. Classified by smoking habits, smoking groups had significantly greater number of decayed teeth(p=0.035) and CPITN(p=0.001) than non-smoking groups. Multiple regression analysis of the study data revealed that the significant factors influencing number of decayed teeth were number of brushing, sex and intra-oral observation (explanatory power of 14.2%). The significant factors for number of filled teeth were sex, intra-oral observation, use of aid tools, frequency of brushing, subjective health conditions and drinking of sweet beverages(explanatory power of 18.2%), those for number of missing teeth, number of brushing and age(explanatory power of 13.9%) those for DMFT, number of brushing, sex, use of dental service, age(explanatory power: 13.5%), and those for CPITN included smoking habits, use of dental service, use of aid tools (explanatory power: 10.8%). Conclusions: The study results revealed that the dental health behavior of the elderly population is in poor conditions and their consequent intra-oral health conditions are not good. To improve their oral conditions, public campaign and education will be needed to modify unhealthy dental health behaviors.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.515-519
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• 2004

Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOV A and the Scheffe test at the 95% confidence level. The results of this study were as follows: 1. The mean fracture strength decrease in following sequence Group 1 (4558.90{\;}\pm{\;}77.40{\;}N$), Group 2 ($494.07{\;}\pm{\;}123.98{\;}N) and Group 3 ($267.33{\;}\pm{\;}27.02{\;}N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.

• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.21.1-21.15
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• 2023

Objectives: This study evaluated the effects of Biodentine (BD), Bio-C Repair (BCR), and mineral trioxide aggregate (MTA) plug on the fracture resistance of simulated immature teeth with replacement root resorption (RRR) and in vitro-induced osteoclastogenesis. Materials and Methods: Sixty bovine incisors simulating immature teeth and RRR were divided into 5 groups: BD and BCR groups, with samples completely filled with the respective materials; MTA group, which utilized a 3-mm apical MTA plug; RRR group, which received no root canal filling; and normal periodontal ligament (PL) group, which had no RRR and no root canal filling. All the teeth underwent cycling loading, and compression strength testing was performed using a universal testing machine. RAW 264.7 macrophages were treated with 1:16 extracts of BD, BCR, and MTA containing receptor activator of nuclear factor-kappa B ligand (RANKL) for 5 days. RANKL-induced osteoclast differentiation was assessed by staining with tartrate-resistant acid phosphatase. The fracture load and osteoclast number were analyzed using 1-way ANOVA and Tukey's test (α = 0.05). Results: No significant difference in fracture resistance was observed among the groups (p > 0.05). All materials similarly inhibited osteoclastogenesis (p > 0.05), except for BCR, which led to a lower percentage of osteoclasts than did MTA (p < 0.0001). Conclusions: The treatment options for non-vital immature teeth with RRR did not strengthen the teeth and promoted a similar resistance to fractures in all cases. BD, MTA, and BCR showed inhibitory effects on osteoclast differentiation, with BCR yielding improved results compared to the other materials.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.202-207
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• 2000

The purpose of study was to compare the caries experience between the mentally retarded(MR) and the normal(N) children and adolescents and to survey the dental visit frequency. preventive dental care, and tooth-brushing behavior of the mentally retarded. Two hundred and fifty MR and two hundred and ten N subjects were selected for the study. 1. The number of teeth which had experienced caries was 3.28 in MR and 4.66 in N. The number of decayed teeth was 2.24 in MR and 1.50 in N. The number of filled teeth was 0.71 in MR and 3.06 in N Filled teeth rate was 19.78% in MR and 58.89% in N The differences between MR and N were all significant(P<0.01). 2. Dental visit frequency of MR was 1.15 per year, and the 51.2% of MR did not visit the dental clinic for the last one year. 38.0% of MR had received the preventive dental care. 3. Toothbrushing frequency per day was 2.16 and the toothbrushing time for 78.3% of MR was less than two minutes. 51.2% of MR brushed their teeth by themselves, 13.3% did with the help of the carers, and 35.5% totally depended on the carers. In conclusion, MR experienced less dental caries than N, had more untreated caries than N, and had need for regular preventive dental care.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.3
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• pp.483-495
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• 1998

The purpose of this study was to evaluate the human pulpal response to Dentin Bonding Desensitizer. Class V cavities were prepared on the buccal surfaces of the first premolars and Dentin Bonding Desensitizer(ALL-BOND Desensitizer, Bisco, Inc. U.S.A.) was applicated in ten experimental teeth, or ZOE(PROPAC, GC Co. TOKYO, JAPAN) cement in eight control teeth and cavities were filled with light curing glass ionomer(Fuji II LC, GC Co., TOKYO, JAPAN). At 3-day and 25-day postoperative interval. pulpal response was observed and evaluated histologically with light microscope. The results were as follows. ; 1. At 3-day postoperative interval, the control teeth were grade 1 inflammatory cell response and grade 1 connective tissue response. 2. At 25-day postoperative interval, all control teeth were grade 1 inflammatory cell response and in three control teeth grade 1 connective tissue response were observed, and one teeth showed grade 2 connective tissue response. 3. At 3-day postoperative interval, the experimental teeth were grade 1 inflammatory cell response and grade 1 connective tissue response. Below the cavity, a few inflammatory cell(PMNs) in odontoblastic layer, increased blood vessels and pulpal cells were seen and this pulpal response was similar to control teeth. 4. At 25-day postoperative interval, in four experimental teeth grade 1 inflammatory cell response and grade 1 connective tissue response were observed, and one experimental teeth showed mild inflammatory response. 5. At 3-day and 25-day postoperative interval, no reparative dentin deposition was seen. 6. Both experimental and control group, pulpal response showed difference between 3 and 25-day of postoperative interval. In control teeth, increased predentin and pulpal cells were seen and in experimental teeth, congestion of blood vessels and increased pulpal cells were seen. In conclusion, the pulpal irritation due to this Dentin Bonding Desensitizer was not severe, and it was considered that the agent was not harmful to the human pulp.

• Journal of dental hygiene science
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• v.13 no.1
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• pp.1-12
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• 2013

This study aims to measure oral health knowledge and practice level among dental clinic patients, and examine their relationships with decayed, missing and filled teeth (DMF) index and the oral health-related quality of life (QOL). Empirical data have been collected from 311 patients through structured questionnaires and dental examinations conducted in Busan area. According to the analysis of causal relationship, oral health knowledge turned out to have a direct effect on oral health practices, which exerted both direct and indirect effects on DMF index and oral health-related QOL. While DMF index directly affected the oral health-related QOL, oral health knowledge proved to have only an indirect effect on DMF index and oral health-related QOL, mediated by oral health practices. Considering all these findings, effective oral health education and other intervention programs should focus on motivating people to participate in the active practices of desirable oral health behaviors, which will lead to the prevention of oral diseases and the subsequent improvement in the QOL.

• Journal of dental hygiene science
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• v.11 no.3
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• pp.181-187
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• 2011

This study conducted oral examinations and individual interviews on migrant multi-cultural family women in Daegu and measured their socio-demographic characters, oral health conditions and OHIP-14 in an aim to investigate the relevance between the oral health of migrant multi-cultural family women living in some big cities and their quality of life. Based on data finally collected from 189 women, the t-test, ANOVA and binary logistic regression analysis were conducted and the conclusions are as follows: The average number of decayed teeth was 2.23, loss teeth was 1.48, and treated teeth was 5.58. Women from the Philippines had more number of loss teeth than those from other countries, and women from China relatively had a small number of filled permanent teeth. The quality of life related to oral health was found to be poor in proportion to the number of loss teeth. A comparison of life quality related to oral health depending on loss teeth showed that life quality related to oral health was lowest in the areas of mental discomfort, physical ability decrease, mental ability decrease, social ability decrease and social disadvantage. Life quality related to oral health was found to be low in proportion to the number of permanent teeth with decay experience and poor monthly household income, which shows that the number of permanent teeth with decay experience and monthly income are mostly related to life quality related to oral health. As migrant multi-cultural family women's life quality related to oral health is low in proportion to the number of loss teeth and decayed teeth, it needs to develop a program to improve their oral healthrelated life quality and conduct follow-up research to verify its effect.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.617-617
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• 2003

I. Objectives This study was done to evaluate whether or not there are any differences in microleakage of the class 5 composite restoration that were filled at the smooth surface and the proximal surface respectively. In addition any differences between small and large-sized restoration were also studied. II. Materials and Methods Total sixty-four class 5 resin restorations, sixteen per group, were made in the permanent teeth. Two-sized cavities, small ($2{\;}{\times}{\;}2{\;}{\times}{\;}1.5{\;}mm$) and large ($4{\;}{\times}{\;}2{\;}{\times}{\;}1.5{\;}mm$), were filled at the smooth surface and the proximal surface each.(omitted)

• Journal of the korean Society of Automotive Engineers
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• v.3 no.2
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• pp.27-33
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• 1981

In the paper, it was attempted to verify how the strength around fillet area of shifted gear would be affected by variables such as number of teeth, shifted value, and diametral pitch. Thereafter, the Lewis' tooth factor of the shifted gear was computed in terms of previously mentioned variables in order to observe the characteristics of stress change related from tooth factor and tooth number with the parameter of shifted values and diametral pitches. From the results of quasi-theoretical values by Finite Element Method(F.E.M.)and experimental values through the photo-elastic tests, the followings were identified. The more the number of gear teeth increased, the more the profile of the tooth became close to that of rack, and accordingly the stresses in the fillet area decreased significantly in certain range. Furthermore, as the shifted value and pressure angle increase the stresses tend decrease. Moreover, the stresses analyzed by F.E.M. in the filled area became around 1.22 times larger than the stresses computed by Lewis' form factor, and this is supposed as on influence of the stress concentration in fillet area.