• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.4
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• pp.396-408
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• 2023

The purpose of this study was to compare the proximal surface contour, size of contact area, and volume difference before and after restoration in artificial teeth of primary molars during proximal composite resin restoration using different matrix systems. Four types of artificial teeth were restored with composite resin using sectional matrix systems-Palodent V3 Sectional Matrix System and myJunior Kitand a circumferential matrix system-Tofflemire Matrix System-and modeled threedimensionally for analysis. When sectional matrix systems were used, there was a higher probability of concave proximal surface contour and simultaneously greater contact area and volume. This is attributed to the dead soft properties of the matrix band used in sectional matrix systems, which can lead to deformation of the band and hence an excessive amount of resin applied around the contact point. Additionally, the rubber wedge in the sectional matrix system may not help the matrix band fit into the cavity. Therefore, based on the findings of this study, morphological aspects need to be carefully considered for proximal composite resin restoration of primary molars using sectional matrix systems.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.419-430
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• 2000

The purpose of this study was to compare the microleakage pattern of preventive resin restoration using conventional composite resin and flowable composite resin that recently developed. 60 sound premolar teeth were allocated to three groups. Flowable composite resin was used for the experimental groups(Group I and II) and conventional resin for the control group(Group III). After composite filling and sealant application, all teeth were thermocycled and evaluated for microleakage under light microscope. Additionally, a variety of voids formed inside restorations were also evaluated. Data were analyzed statistically using Kruskal-Wallis test and/or Mann-Whitney U-test. The results of the present study were as follows. 1. Microleakage found in all samples was only limited to the interface of restoration margin and enamel. 2. The flowable composite resin groups (Group I, II) generally showed less microleakage than control groups (conventional preventive resin restoration) (p<0.05) 3. Various types of voids were observed in most specimens. Especially, there was a tendency for more and larger voids to be found in group I, II than group III (p<0.05).

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.313-320
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• 2010

Objectives: The aim of this study was to examine changes in the dentinal fluid flow (DFF) during desensitizing agent application and to compare permeability after application among the agents. Materials and Methods: A Class 5 cavity was prepared to exposure cervical dentin on an extracted human premolar which was connected to a sub-nanoliter fluid flow measuring device (NFMD) under 20 cm water pressure. DFF was measured from before application of desensitizing agent (Seal&Protect, SP; SuperSeal, SS; BisBlock, BB; Gluma desensitizer, GL; Bi-Fluoride 12, BF) through application procedure to 5 min after application. Results: DFF rate after each desensitizing agent application was significantly reduced when compared to initial DFF rate before application (p < 0.05). SP showed a greater reduction in DFF rate than GL and BF did (p < 0.05). SS and BB showed a greater reduction in DFF rate than BF did (p < 0.05). Conclusions: Characteristic DFF aspect of each desensitizing agent was shown in NFMD during the application procedure.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.91-108
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• 2000

Most of cervical abrasion and erosion lesions show gingival margin where the cavosurface angle is on cementum or dentin. Composite resin restoration of cervical lesion shrink toward enamel margin due to polymerization contraction. This shrinkage has clinical problem such as microleakage and secondary caries. Several methods to diminish contraction stress of composite resin restoration, such as modifying cavity form and building up restorations in several increments have been attempted. The purpose of this study was to compare polymerization contraction stress of composite resin in Class V cavity subjected to cavity forms and placement methods. In this study, finite element model of 5 types of Class V cavity was developed on computer tomogram of maxillary central incisor. The types are : 1) Box cavity 2) Box cavity with incisal bevel 3) V shape cavity 4) V shape cavity with incisal bevel 5) Saucer shape cavity. The placement methods are 1) Incisal first oblique incremental curing 2) Bulk curing. An FEM based program for light activated polymerization is not available. For simulation of curing dynamics, time dependent transient thermal conduction analysis was conducted on each cavity and each placement method. For simulation of polymerization shrinkage, thermal stress analysis was performed with each cavity and each placement method. The time-temperature dependent volume shrinkage rate, elastic modulus, and Poisson's ratio were determined in thermal conduction data. The results were as follows : 1. With all five Class V cavifies, the highest Von Mises stress at the composite-tooth interface occurred at gingival margin. 2. With box cavity, V shape cavity and saucer cavity, Von Mises stress at gingival margin of V shape cavity was lower than the others. And that of box cavity was lower than that of saucer cavity. 3. Preparing bevel at incisal cavosurface margin decreased the rate of stress development in early polymerization stage. 4. Preparing bevel at incisal cavosurface margin of V shape cavity increased the Von Mises stress at gingival margin, but decreased at incisal margin. 5. At incisal margin, stress development by bulk curing method was rapid at early stage. Stress development by first increment of incremental curing method was also rapid but lower than that by bulk curing method, however after second increment curing final stress was the same for two placement methods. 6. At gingival margin, stress development by incremental curing method was suddenly rapid at early stage of second increment curing, but final stress was the same for two placement methods.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.151-159
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• 2021

Since January 2019, insurance coverage for caries treatment of permanent teeth using composite resin in children aged 12 and under has started in South Korea. The purpose of this study was to compare the pattern of permanent molar composite resin restoration aged 12 and under before and after the insurance coverage from January 2009 to March 2020 in the Department of Pediatric Dentistry at Kyung Hee University Dental Hospital at Gangdong. Since the insurance coverage was started in 2019, the frequency of permanent molar composite resin restoration aged 12 and under has increased more than twice. There was a significant change in frequency of resin restoration by shape of cavity comparing before and after the insurance coverage, whereas there was no significant difference in changes by patient age, gender and position of tooth. As accessibility to the permanent tooth composite resin restoration is increased by the insurance coverage, which shows a fair survival rate, it is expected that it could be able to secure oral health in the early permanent dentition aged 12 and under.

• Journal of the Korean Geographical Society
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• v.52 no.1
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• pp.25-53
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• 2017

The ultimate goal of this research is to examine the geographical characteristics of therapeutic spaces where have been appeared in Wa-dong and Gojan-dong, Ansan-si after the disaster of the MV Sewol. As looking into the inside, the aim of the therapeutic spaces, which cover each target group (victims) individually, is various and different because the disaster of the MV Sewol generated various direct and indirect victims requiring healing. The therapeutic spaces are estimated at about 10 organizations and are leaded by private agents predominantly. Furthermore, the therapeutic spaces are located near, but are aside from Danwon high school where many students are reported killed and injured in the incident. And the therapeutic spaces provide simple and repetitive diversions, for example, having a meal, knitting and studying, rather than special programs to restore a broken daily life to the original state. On the basis of such a background, the geographical characteristics of the therapeutic spaces related to the disaster of the MV Sewol can be summarized as follows; first, it seems that target groups accept the therapeutic spaces as the concept of place gradually. Even though most of the therapeutic spaces were suggested by third parties at first, target groups are involved in the management and recollection of their own therapeutic spaces as well as the plan for a future direction now; and consider the therapeutic spaces as exclusive properties. Second, the disaster of the MV Sewol have embedded collective trauma to not only direct victims, but extensive groups such as parents, brothers and sisters, relatives, friends and neighbors as noted earlier. Therefore, the therapeutic spaces support comprehensive target groups; but each therapeutic space is not overlapped each other. However, to solve collective trauma in a local community effectively, the therapeutic spaces are networked closely and build a regular cooperative system. Third, a continuous memory is mentioned as an important point to overcome collective trauma, but some phenomena such as fatigue and conflict with neighbors, out-migrants and a faded atmosphere as time passes act as risk factors in Ansan-si. To keep a continuous memory, the therapeutic spaces attempt the recovery of local communities and devise various events, for example, cultural performances; furthermore, are closely connected with external organizations.