• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.265-269
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• 2014

Objectives: To evaluate the effect of different ultrasonic tip designs on intraradicular post removal. Materials and Methods: The crowns of forty human canine teeth were removed, and after biomechanical preparation and filling, the roots were embedded in acrylic resin blocks. The post spaces were made, and root canal molding was performed with self-cured acrylic resin. After casting (Cu-Al), the posts were cemented with zinc phosphate cement. The specimens were randomly separated into 4 groups (n = 10), as follows: G1 - no ultrasonic vibration (control); G2 - ultrasonic vibration using an elongated cylindrical-shaped and active rounded tip; G3 - ultrasonic vibration with a flattened convex and linear active tip; G4 - ultrasonic vibration with active semicircular tapered tip. Ultrasonic vibration was applied for 15 seconds on each post surface and tensile test was performed in a Universal Testing Machine (Instron 4444 - 1 mm/min). Results: G4 presented the highest mean values, however, with no statistically significant difference in comparison to G3 (p > 0.05). G2 presented the lowest mean values with statistically significant difference to G3 and G4 (p < 0.05). Conclusions: Ultrasonic vibration with elongated cylindrical-shaped and active rounded tip was most effective in reducing force required for intraradicular post removal.

• Korean Journal of Remote Sensing
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• v.13 no.1
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• pp.31-46
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• 1997

In recent years, as remotly-sensed image processing technologies have been improved and spread widely in the application areas, many new requirements for the image processing technologies have arisen. However, it is difficult and costly to access remotely-sensed image processing systems. Moreover, these systems have thier own processing facilities which are not easily accessible for general users. In this paper, those problems are challenged by adopting Internet as a universal information network for accessing remotly-sensed image DBMS and by allowing users to work remotely on the image processing. A remotly-sensed image processing system which can be accessed via Internet was designed and implemented. This system can be used to manipulate images over remote DBMS. The Illustra object-oriented relational DBMS with CGI(Common Gateway Interface) web interface was used in this project. The client consists of a WWW(World Wide Web) Netscap$e^{TM}$ browser, and the server consists of HTTPD(Web daemon), Illustra DBMS and Java modules in order to process the image being displayed. The developed system was tested on LAN environment and the service response time met the requirements.

• Health Policy and Management
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• v.31 no.4
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• pp.387-398
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• 2021

Moon Jae-in Care can be seen as a 2.0 version of Roh Moo-Hyun Care. Just as Roh Care failed to achieve its coverage rate goal and 30% share of public beds, Moon Care also failed to achieve its expected goal. The reason is that it followed Roh Care's failed strategy. Failure to control non-covered services has led to a long way to achieve a 70% coverage rate and induced the expansion of voluntary indemnity insurance, resulting in increased public burden. The universal coverage of non-covered services caused an immediate backlash from doctors. And Moon government also failed to control the private insurance market. The expansion of publicly owned beds has not become realized and has not obtained public support. Above all, it failed to overcome the resistance of doctors and failed to obtain consent from budget power groups in the cabinet for public investment. It was also insufficient to win the support of civic groups. Communication with interested groups failed and the role of private health care providers was neglected. The next government should also continue to strengthen health care coverage, but it should prioritize preventing medical poor and create a consensus with both medical providers and consumers for the control of non-covered services. Ahead of the super-aged society, the establishment of linkage between medical services and long-term care and visiting health care or welfare services is an important task. All public and private provisions and resources should be utilized in the view of a comprehensive public health perspective, and public investment should be input in sectors where public medical institutions can perform more effective functions. The next government, which will be launched in 2022, should design a new paradigm for health care in the face of a period of transformation, such as the coming super-aged society in 2026 and the Fourth Industrial Revolution, and recognize that the capabilities of the health care system represent the nation's overall capacity.

• The Journal of Advanced Prosthodontics
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• v.13 no.5
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• pp.269-280
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• 2021

PURPOSE. The objective of this study was to evaluate the effect of thickness reduction and fatigue on the failure load of monolithic zirconia crowns. MATERIALS AND METHODS. 140 CAD-CAM fabricated crowns (3Y-TZP, inCorisTZI, Dentsply-Sirona) with different ceramic thicknesses (2.0, 1.5, 1.0, 0.8, 0.5 mm, respectively, named G2, G1.5, G1, G0.8, and G0.5) were investigated. Dies of a mandibular first molar were made of composite resin. The zirconia crowns were luted with a resin composite cement (RelyX Unicem 2 Automix, 3M ESPE). Half of the specimens (n = 14 per group) were mouth-motion-fatigued (1.2 million cycles, 1.6 Hz, 200 N/ 5 - 55℃, groups named G2-F, G1.5-F, G1-F, G0.8-F, and G0.5-F). Single-load to failure was performed using a universal testing-machine. Fracture modes were analyzed. Data were statistically analyzed using a Weibull 2-parameter distribution (90% CI) to determine the characteristic strength and Weibull modulus differences among the groups. RESULTS. Three crowns (21%) of G0.8 and five crowns (36%) of G0.5 showed cracks after fatigue. Characteristic strength was the highest for G2, followed by G1.5. Intermediate values were observed for G1 and G1-F, followed by significantly lower values for G0.8, G0.8-F, and G0.5, and the lowest for G0.5-F. Weibull modulus was the lowest for G0.8, intermediate for G0.8-F and G0.5, and significantly higher for the remaining groups. Fatigue only affected G0.5-F. CONCLUSION. Reduced crown thickness lead to reduced characteristic strength, even under failure loads that exceed physiological chewing forces. Fatigue significantly reduced the failure load of 0.5 mm monolithic 3Y-TZP crowns.

• The korean journal of orthodontics
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• v.49 no.1
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• pp.21-31
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• 2019

Objective: This study was performed to explore the effect of different bracket, archwire, and ligature combinations on resistance to sliding (RS) and rotational control in first-order angulation. Methods: Three types of brackets (multi-level low friction [MLF], self-ligating, and conventional brackets) coupled with four nickel-titanium archwires (0.012, 0.014, 0.016, and 0.018-inch diameter) and two stainless steel ligatures (0.20 and 0.25 mm) were tested in different first-order angulations ($0^{\circ}$, $2^{\circ}$, $4^{\circ}$, $6^{\circ}$, $8^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$) by using an Instron universal mechanical machine in the dry state at room temperature. RS value was evaluated and compared by one-way ANOVA. Results: Under the same angulation, the RS values showed the following order: conventional brackets > MLF brackets > self-ligating brackets. The RS was the highest for conventional brackets and showed a tendency to increase. The RS for MLF brackets coupled with thinner archwires and ligatures showed a similar tendency as the RS for the self-ligating bracket. In contrast, the RS for MLF brackets coupled with thicker archwires and ligatures increased like that for conventional brackets. MLF brackets showed the greatest range of critical contact angles in first-order angulation. Conclusions: The RS in first-order angulation is influenced by bracket design, archwire, and ligature dimension. In comparison with self-ligating and conventional brackets, MLF brackets could express low friction and rotational control with their greater range of critical contact angles.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.148-159
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• 2019

The aim of this study was to investigate whether there is the association between parents residence type and connubial bliss mediated to Korean married women. A total of 3,851 married women were selected from the database of the Fourth Korea Longitudinal Survey of Women and Families(KLoWF) in 2015-2016. In univariate analysis, there was statistically significant differences parents residence type, couple activity, family care and connubial bliss according to socio-demographic characteristics. Moreover, when the parents residence type is short distance, connubial bliss is higher, couple activity is more active and family care is more friendly attitued. By the result of sobel test, parents residence type was indirectly influenced on connubial bliss mediated to couple activity and family care. However, parents residence type was no directly influenced on connubial bliss mediated. The results of these studies will help design policy plans to improve the relationship between spouses and family members in a universal nuclear family society.

• Journal of Korean Library and Information Science Society
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• v.50 no.2
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• pp.25-42
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• 2019

This study identified the experiences that the disabled actually feel in the library space in the face of growing social demands for spatial functions in public libraries. This study also tried to determine the requirements for the space that disabled wanted. For the research, 15 subjects were selected for each of the five people who were blind, deaf, and handicapped with experience using the library and individual in-depth interviews were conducted for the research. The study found that the experience of the disabled in the library space differed by type of disability and generally more negative experiences were found than positive ones. Misperception about the disabled of library staff and the non-disabled were having a significant impact on the disabled's negative experience for library space. There were a wide variety of opinions on the requirements for library space and there were generally negative perceptions about the current level of library space for the Integrated library service space.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.95-104
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• 2019

PURPOSE. To evaluate the effect of surface treatments and repair materials on the shear bond strength and to measure the fracture toughness of CAD/CAM provisional restoration materials. MATERIALS AND METHODS. Four CAD/CAM (3D printing: Nextdent C&B and ZMD-1000B Temporary, CAD/CAM resin block: Yamahachi PMMA disk and Huge PMMA block) and four conventional (monometacrylate: Jet and Alike, dimetacrylate: Luxatemp and Protemp 4) materials were selected to fabricate disk-shaped specimens and divided into six groups according to surface treatment (n=10). CAD/CAM materials were repaired with Jet or Luxatemp, while conventional materials were repaired with their own materials. The shear bond strength was measured by using universal testing machine. Ten rectangular column-shaped specimens for each material were fabricated to measure the fracture toughness by single edge v notched beam technique. Statistical analysis was performed by one-way ANOVA. RESULTS. The highest shear bond strength of CAD/CAM materials was achieved by SiC paper + sandblasting. It was also accomplished when repairing 3D printing materials with Luxatemp, and repairing CAD/CAM resin blocks with Jet. Yamahachi PMMA disk showed the highest fracture toughness. Nextdent C&B showed the lowest fracture toughness value but no statistically significant difference from Alike and Luxatemp (P>.05). CONCLUSION. In order to successfully repair the CAD/CAM provisional restoration, mechanical surface treatment and appropriate repair material according to the CAD/CAM material type should be selected. The CAD/CAM provisional materials have proper mechanical properties for clinical use as compared to conventional materials.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.2
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• pp.51-62
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• 2019

Purpose: This study aims to examine spatial characteristics of ambulatory care department Chronologically through case studies; and to consider the social implication of these spatial changes. Methods: In this study, a total of eight ambulatory care departments, one or two for each period, were selected in order to analyze the spatial characteristics. Results: First, since the 1990s, the outpatient department of the US has been changed into a patient-centered space by providing high quality outpatient medical services through individual exam room planning. Second, the exam room has been changed from open/semi-open/group exam room to individual exam room since 1990, and the trend is shifting from the cluster type to the modular type consisting of universal exam rooms in order to achieve the flexibility of exam room. Third, the diagnostic/testing area has been deployed to the ambulatory clinic to enable 'one-stop shopping' for patients-centered care since 1990s, however, it has been disappearing since 2000 due to Reduce medical expenses. Fourth, the Central Nursing Station type first appeared in the outpatient department In the 2000s, followed by the type of decentralized nursing station type since 2010s. And fifth, the area of medical support has been placing to be concentrated on one place due to the Lean Design strategy since 2010. Implications: In the future, it is expected that Korea will be more focused on efficiency, visual control, and flexibility in the planning of the ambulatory care department as in the case of the United States.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.326-333
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• 2020

Purpose: The purpose of this study was to evaluate the effects of various zirconia surface treatment methods on shear bond strength with resin cements. Methods: We prepared 120 cylindrical zirconia specimens (⌀10 mm×10 mm) using computer-aided design/computer-aided manufacturing (CAD/CAM). Each specimen was randomly subjected to one of four surface treatment conditions: (1) no treatment (control), (2) airborne-particle abrasion with 50 ㎛ of Al2O3 (A50), (3) airborne-particle abrasion with 125 ㎛ of Al2O3 (A125), and (4) ZrO2 slurry (ZA). Using a polytetrafluoroethylene mold (⌀6 mm×3 mm), we applied three resin cements (Panavia F 2.0, Super-Bond C&B, and Variolink N) to each specimen. The shear bond strength tests were performed in a universal testing machine. The surfaces of representative specimens of each group were evaluated under scanning electron microscope. We used one-way analysis of variance (ANOVA), two-way ANOVA, and post hoc Tukey honest significant difference test to analyze the data. Results: In the surface treatment method, the A50 group showed the highest bond strength, followed by A125, ZA, and control groups; however, no significant difference was observed between A50 and A125, A125 and ZA, and ZA and control (p>0.05). Among the resin cements, Super-Bond C&B showed the highest shear bond strength, followed by Panavia F 2.0 and Variolink N (p<0.05). Conclusion: Within the limitations of this study, application of airborne-particle abrasion and ZrO2 slurry improved the shear bond strength of resin cement on zirconia.