• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.35-47
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• 2022

Purpose : As the number of patients with systemic diseases is increasing in the old, the relevance of oral health is gaining particular research interest. To provide fundamental resources for dental services, this study examined the relationship between doctors' diagnoses of circulatory diseases and patients' awareness of oral health and oral care behaviors. Methods : SPSS 26.0 was used to assess various variables, including doctor's diagnosis of circulatory diseases, gender, age, household income quintile, participation in economic activity, marital status, subjective level of oral health awareness, mastication discomfort, speaking and chewing discomfort, dental inspection, use of oral care goods, teeth brushing during the previous day, and untreated oral conditions. Results : The circulatory diseases suffered by the subjects were as follows: 56 % high blood pressure, 36 % dyslipidemia, 6 % stroke, and 8 % myocardial infarction or angina. A higher age meant a higher diagnosis rate of high blood pressure (p<.001) and stroke (p<.001). Those with dyslipidemia showed a higher rate of receiving oral inspection (p=.040), and an untreated oral condition was more frequently observed among those not diagnosed with the disease (p=.035). The subjects who were not diagnosed with stroke showed a higher rate of oral inspection (p<.001), while those who had a prior experience of stroke suffered a higher rate of mastication discomfort (p=.020). People who had high blood pressure showed a lower rate of using oral care goods (p<.001), and those diagnosed with stroke showed a lower rate of brushing teeth the previous day. Conclusion : This study found a correlation between the diagnosis of circulatory diseases and the awareness of oral health and oral care behavior. Consequently, oral health education should be included in mental health-related education, and customized training to teach teeth brushing and the use of oral care goods should be provided to patients with circulatory diseases during dentist visits.

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.735-758
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• 1994

This study was designed to investigate the displacements and reaction forces of teeth caused by the application of the rectangular shape-memory arch wires with curve of Spee. Computer-aided three dimensional finite element method was adopted. This finite element model consists of brick element for teeth, beam element for the wire, and contact element for the periodontal ligament. And the application of the MEAW(Multiloop Edgewise Arch Wire) was also studied so that the results of the two methods can be compared each other. Total number of the nodes and elements were found to be 5925 and 4031, repectively. In addition, several types of elastics and corresponding displacements and reaction forces were examined. The findings of this study were as follows: 1. When the rectangular shape-memory arch wire with curve of Sun was used alone, the intrusion and labioversion was noticeable on the upper incisors, while the upper molars showed less intrusion. With MEAW, the intrusion and labioversion of the upper incisors were slightly larger than those when the shape-memory arch wire was used, but on the upper molars the opposite result was obtained with respect to the intrusion. 2. The shape-memory arch wire with the vertical elastics caused the larger downward displacement on the upper canine than that when the MEAW was used with the vertical elastics. However, the downward displacement of the upper incisors was larger in MEAW. The uprighting and buccoversion of the molars were observed in both cases. 3. The use of the Class II or III elastics showed the extrusion and changes in torque of the corresponding teeth. The downward displacement of the upper canine was increased when the Class II and vertical elastics were applied simultaneously, but it was decreased when both of the Class III and vertical elastics were used.

• Korean Journal of Cleft Lip And Palate
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• v.6 no.2
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• pp.69-89
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• 2003

The purpose of this study was to examine and analyze the basic conditions of dental health of cleft lip and palate patients at early mixed dentition (7-year-old, experimental group A) and early permanent dentition period (12,13-year old, experimental group B) and compare them with those of normal children. The sample was consisted of 25 patients at the age of 7 years, 15 at the age of 12 years and 5 at the age of 13 years. Two trained dentists examined orthopantomographs and clinical photos at the first visit of each patient and distinguished the states by teeth and dental surface and filled them on the prescribed forms. DMF rate, DMF index, FT rate, mean number of permanent teeth with fissure sealants, DMFS index and mean percentage of caries experienced maxillary anterior 6 teeth by tooth type are calculated and compared to those of other studies examined normal children. Oral hygiene of experimental groups is poorer than control groups'. Preventive and treatment rate of experimental groups' are lower than control groups'. More concem and effort are needed about prevention and treatment of dental caries of cleft lip and palate patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.493-498
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• 1998

Computed tomography(CT) has become more widely available in recent years and is recognized as an important diagnostic tool for complex disease and condition of the orofacial structure in adults. In pediatric patients, especially in the mixed dentition period, the number of superimposing dental structures in the jaw bone is much greater than in the permanant dentition period. Therefore, in spite of radiation risk, computed tomography should sometimes be used in pediatric patients in order to obtain a precise and valid diagnosis. This case study presents clinical application of computed tomography on patients visiting department of pediatric dentistry in Seoul National University Dental Hospital. The results obtained through these cases were summarized as follow : 1. Localization of impacted teeth using CT allows for efficient treatment planning leading to reduced postoperative complications. 2. In orthodontic traction of impacted permanent teeth, utilization of CT made exact localization of window site and determination of prognosis possible. 3. Use of CT made possible definite diagnosis of lesions in the jaw that were only suspected on plain film radiographs. 4. Careful selection is necessary when applying CT on children due to increased radiation dose and high cost.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.3
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• pp.40-71
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• 1986

By developing a computer program for the systematic design of worm gears, the design formulae and tables of AGMA, JGMA, BS and DIN are analized and compared. The computer program can be used on micro-computers. According to the input data of the reduction ratio, the center distance. the driving torque and the material as design parameters, the program calculate the most efficient worm gear dimension. The variation of the design parameters and other empirical coefficients in case of resulting an inadequate design gear dimension can be easily modified throuth the way of interactive method between the user and the monitoring system of computer. A proposal of the standardization of worm gears was made in which a standard module according to the DIN 323 standard series number was applied. For the more exact and effective calculation of the stress concentration and the deformation of gear teeth, a computer program using the boundary element method is also developed. Even the strength of the special gear shape such as Niemann's "Cavex" gear can be calculated in a short CPU-time. The most effort of this study has been layed on the developing a computer program for the correction of a tooth profile and face width which is most important design factor for an exact and wide teeth contacts under loads, especially by great and wide gears. For this purpose were investigated the tooth stiffness, the mesh interferences and the kinematics and the dynamics of gear mesh. The deflection and the deformation of the gear shaft due to the loads acting on gear and shaft were aslo considered. Some examples have shown the sufficient good status of teeth contact in which the correction of the tooth profile and face width were accomplished due to the calculated results.d results.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.49.1-49.11
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• 2020

Objectives: The aim of this study was to perform a clinical and radiographic analysis of endodontically treated teeth (ETT) restored with cast metal posts (CMPs) or prefabricated glass fiber posts (GFPs) and crowns. Materials and Methods: Fifty ETT were restored with 25 CMPs and 25 GFPs at a private dental clinic between 2001 and 2016. The restorations consisted of 12 all-ceramic crowns, 31 metal-ceramic crowns, and 7 composite resin crowns. Demographic data, type of teeth, type of post-and-core system, time of placement, crown restorations, the number of proximal contacts, the type of antagonist, and reports of any complications after post-and-core placement were recorded for each patient. Assessments were performed at baseline (radiographic) and follow-up (radiographic and clinical). Data were analyzed by the McNemar test, the Pearson χ² test, and Kaplan-Meier survival curves (α = 0.05). The mean follow-up was 67.6 months. Results: No significant difference was observed for any of the radiographic parameters when the baseline and final radiographs were compared. In the clinical evaluation, anatomical form (p = 0.009) and occlusion (p = 0.001) showed significant differences according to the type of crown restoration; specifically, metal-ceramic and all-ceramic crowns outperformed composite resin crowns. Conclusions: CMPs and GFPs showed favorable results for restoring ETT after 6 years of follow-up. All-ceramic and metal-ceramic crowns showed higher survival rates and better clinical outcomes.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.273-280
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• 2020

Upon investigating the dental health of teeth and gum, and the cleanliness of the oral cavity of female college students in the early 20's, it was reported to be that the number of cariogenic bacteria was heavily related to the acidity of saliva or ammonia. Also, cariogenic bacteria and ammonia was found out to be related with proteins (p<0.01), and ammonia, the synthetic product of cariogenic bacteria was heavily related to blood and white blood cells (p<0.01). To conclude, the healthiness of teeth was related to the acidity of saliva and ammonia, the healthiness of gum was related to blood, proteins and white blood cells while the oral hygiene was most likely to be related to ammonia. This result matched to the seven oral disease cause analyses of the saliva analysis apparatus (Sill-Ha ST-4910), which implied further utilization of this data to clinical implications. However, this study is limited to young personnel who does not have any chronic or general diseases; therefore further study is required to generalize this study.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.614-622
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• 1995

Root caries is very frequently developed on exposed root surface after periodontal surgical treatment. In order to determine the anti-caries effect of Nd : YAG laser irradiation on periodontally exposed root surface, 40 mandibular molar teeth that had been extracted due to excessive periodontal destruction were used as the experimental teeth. All teeth were treated by the same procedure as conventional periodontal root treatment, ie thorough scaling, root planing and root conditioning with tetracycline HCl(100mg/ml, 5min.). Within middle one third of root, mesial half surface(20) or distal half surface(20) was randomly irradiated at various power of 1.0W, 2.0W, 3.0W and 4.0W for 60 seconds by non-contact(5mm) delivery of a pulsed Nd : YAG laser(EN.EL.EN060, Italy). The microhardness was measured by Vikers microhardness tester(Wilson, USA) at 2mm/second of jog speed under 100gm load. The difference of microhardness between irradiated side and non-irradiated side was statistically analyzed ANOVA and Duncan's method. Following results were obtained ; 1. The microhardness(Knoop hardness number) was significantly higher in laser irradiated surface than non-irradiated surface(p<0.05). 2. There was no significant difference in microhardness between experimental groups classified by different laser power(p>0.1). The results suggest that Nd : YAG laser irradiation on exposed root suface after periodontal therapy may inhibit the root caries development by enhancing surface microhardness.

• Journal of the korean academy of Pediatric Dentistry
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• v.1 no.1
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• pp.41-47
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• 1974

The dental caries survey of "K" primary school children was performed twice for one year interval and evaluated the transitional trend of dental caries prevalences. The number of children surveyed at the first year, 1973, was 819 boys and 653 girls; and the second year, 1974, was 815 boys and 661 girls aged 6 to 12. Under this survey, the following results were detected: 1. The average df person rate in deciduous teeth was increased by 7.52% in boy, 5.59% in girl and 6.65% of both. 2. The average df Index in deciduous teeth was increased by 0.13 in boy, 0.04 in girl and 0.1 of both. The average dt Index was decreased by 0.59 in boy, 0.64 in girl and 0.61 of both. The average ft Index was increased by 0.73 in boy, 0.68 in girl and 0.71 of both. 3. There showed no significant differences in DMF person rate between 1973 and 1974. 4. The DMFT Index of the permanent teeth was decreased by 0.19 in boy, and increased by 0.22 in girl. There showed no significant differences in both sexes between 1973 and 1974. The average DT Index was decreased by 0.43 in boy, 0.03 in girl and 0.31 of both. The average FT Index was increased by 0.23 in boy; 0.35 in girl and 0.29 of both. The average MT Index showed no significant differences in both sexes between 1973 and 1974.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.300-310
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• 1996

Recently, there have been attempts to obstruct the dentinal tubules and remove the smear layer by way of laser irradiation in the root canal during endodontic treatment. This treatment was designed to make the root canal to be nonporous. Using 33 extracted single rooted teeth, 30 teeth were divided into 3 groups (10 each), and 3 teeth were used as samples for SEM. Using Nd : YAG laser, the control group was not irradiated, experimental group l(1W group) was irradiated with 1W, 15pps, 15sec., 3 times, 6.7mJ and experimental group 2(3W group) was irradiated with 3W, 15pps, 15sec., 3 times 20mJ. Thereafter the roots were immersed in methylene blue for 8 hours, and the dye infiltration pattern was observed under stereomicroscope and canal wall surface change was observed under SEM. The results are as following ; 1. As a result of evaluating the dye infiltration rate of the apical and middle 1/3, there was significant difference between control group and 1W group, control group and 3W group and there was no significant difference between 1 W group and 3W group. 2. In each group, as a result of comparing the dye infiltration rate of the apical and middle 1/3, there was no significant difference in control and 1W group but significant difference in 3W group. 3. In the control group smear layer was scarecely found and many dentinal tubules were found to be open. 4. In the 1W group, the number of dentinal tubules were decreased and gradual changes of the dentin surface could be seen and 3W group, almost no dentinal tubules could be found and the dentin surface was changed a little more and showed signs of partial fusion.