• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3B
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• pp.293-303
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• 2011

An efficient diagonalized approximate factorization algorithm (DAF) is developed for the solution of three-dimensional incompressible viscous flows. The pressure-based, artificial compressibility (AC) method is used for calculating steady incompressible Navier-Stokes equations. The AC form of the governing equations is discretized in space using a second-order-accurate finite volume method. The present DAF method is applied to derive a second-order accurate splitting of the discrete system of equations. The primary objective of this study is to investigate the computational efficiency of the present DAF method. The solutions of the DAF method are evaluated relative to those of well-known four-stage Runge-Kutta (RK4) method for fully developed and developing laminar flows in curved square ducts and a laminar flow in a cavity. While converged solutions obtained by DAF and RK4 methods on the same computational meshes are essentially identical because of employing the same discrete schemes in space, both algorithms shows significant discrepancy in the computing efficiency. The results reveal that the DAF method requires substantially at least two times less computational time than RK4 to solve all applied flow fields. The increase in computational efficiency of the DAF methods is achieved with no increase in computational resources and coding complexity.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.5
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• pp.339-348
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• 2022

Background: To compare the anesthetic efficacy of supplemental buccal infiltration (BI) (1.7 ml) versus intraligamentary (IL) injection containing 0.4 ml of 4% articaine with 1:100.000 epinephrine after an inferior alveolar nerve block (IANB) with 1.7 ml 2% lidocaine in the first and second mandibular molars diagnosed with irreversible pulpitis (IP). Methods: One hundred subjects diagnosed with IP of either the mandibular first (n = 50) or second molars (n = 50) and failed profound anesthesia following an IANB were selected. They randomly received either the IL or BI techniques of anesthesia. Pain scores on a 170 mm Heft-Parker visual analog scale were recorded initially, before, and during supplemental injections. Furthermore, pulse rate was measured before and after each supplemental injection. During the access cavity preparation and initial filing, no or mild pain was assumed to indicate anesthetic success. The chi-square test, Mann-Whitney U test, and independent samples t-test were used for the analyses. Results: The overall success rates were 80% in the IL group and 74% in the BI group, with no significant difference (P = 0.63). In the first molars, there was no significant difference between the two techniques (P = 0.088). In the second molars, IL injection resulted in a significantly higher success rate (P = 0.017) than BI. IL injection was statistically more successful (P = 0.034) in the second molars (92%) than in the first molars (68%). However, BI was significantly more successful (P = 0.047) in the first molars (88%) than in the second molars (64%). The mean pulse rate increase was significantly higher in the IL group than in the BI group (P < 0.001). Conclusions: Both the IL and BI techniques were advantageous when used as supplemental injections. However, more favorable outcomes were observed when the second molars received IL injection and the first molars received BI.

• Journal of the Korea Society of Computer and Information
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• v.27 no.6
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• pp.87-93
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• 2022

This study was conducted to use as basic data to increase the oral examination rate by analyzing Whether to undergo oral examination and the Factors Affecting the unexamined Oral Examination in Cancer Patients. These factors were analyzed using the results from 376 cancer patients in 7th Korea national health and nutrition examination survey. The data were analyzed complex sample frequency analysis and chi-square analysis, multiple logistic regression by using SPSS/WIN 26.0 program. 38% of cancer patients had oral examination and 62% did not. The Factors Affecting the unexamined Oral Examination increased by 3.641 times in over 70 years of age and by 3.928 times in graduating less than elementary school, by 3.740 times in the low-income group, 2.050 times in less than 2 brushing times a day, by 2.533 times in the chewing-problems group, by 2.746 times in speech problems group. The study results show that the oral examination rate of cancer patients was very low. It is necessary to to expand education on the importance of oral care and oral examination in consideration of oral complications and to actively introduce a customized oral health management program for cancer patients.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.4
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• pp.222-232
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• 2022

Purpose: This study was to investigate the dentists' experience and awareness of foreign body ingestion and aspiration during dental prosthetic treatment. Materials and Methods: A survey of 157 dentists working at 108 dental institutions in Daejeon and Chungcheong provinces was carried out and frequency analysis was conducted. Chi-square test was conducted to find out the difference between the sociodemographic data and experience of foreign body ingestion and aspiration of patients and independent sample t-test was conducted to find out the difference in awareness depending on whether receiving related education. Results: The percentage of dentists experiencing dropping foreign body into patients' oral cavity was 99.4% and the percentage of dentists experiencing foreign body ingestion and aspiration of patients was 53.5%. There were more dentists who experienced foreign body ingestion and aspiration of patients in male than female, longer working career, and general practitioners than specialists (P < .05). 50.3% of the respondents received related education. When they receive related education, they had low degree of concern, high confidence in coping with situations, and low willingness to receive education in the future (P < .05). Conclusion: The percentage of foreign body dropping was 16% higher in prosthetic treatment than general treatment. The percentage of dentists with experience of foreign body ingestion and aspiration of patients was 53.5%. Among them, 92.9% experienced foreign body ingestion of patients and 7.1% of them experienced foreign body aspiration of patients.