• Analytical Science and Technology
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• v.24 no.5
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• pp.336-344
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• 2011

The study attempted to find out any effect to prevent photo aging of epoxy resin used for conservation by way of adding UV stabilizer, one of plastic additives. Specimens were made by adding HALS and UVA UV stabilizer as each concentration to 3 kinds of epoxy resin, which are most frequently used for artifacts joining and restoration process, and aging effects were investigated through Color change, SEM, contact angle, FTIR analysis during UV aging experiments. Last, usage suitability was checked when UV stabilizer was added through Universal Tensile strength tester. In result, it is impossible to prevent decomposition of chemical structure in spite of adding UV stabilizer but in the case of epoxy A and R, it is believed that photo aging such as yellowing or crack can be minimized without giving a big influence to adhesive strength of epoxy resin through adding less than 0.1% of UVA. It is expected that above will solve photo aging problem of epoxy resin used for joining and restoration of artifacts and will extend its life as joining and restoration materials.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.41-48
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• 2004

Statement of problem : The Cement as well as restoration required esthetics for making natural color restoration. Purpose : The purpose of this research is to evaluate color stability of restoration intermediated by resin cement which is used for cementation of all ceramic crown. Material and method : After making Empress 2 ingot into the size of $10mm{\times}10mm{\times}1mm$ according to indication, it glazed and made 48 Empress 2 blocks. Three kinds of resin cement(Rely-X, Variolink 2, Choice) having same shade cemented between Empress 2 blocks and Ivory shade tiles and made 48 specimens in the thickness of $30{\mu}m$ and $80{\mu}m$. After measureing color difference using spectorphotomenter, the result of this study were as follows. Results : The color difference of resin cement used in experiment increased in the order Rely-X, Variolink 2. As the thickness of cement increases, the color difference of all kinds of cement found statistically sifnificant difference but, this result is clinically acceptable. Conclusion : More resarch would have to be done in order to decrease the color difference as cement's thickness.

• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.65-68
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• 2010

Due to the improvement of the composite resin and esthetic desire of the patient, amalgam restoration has been replaced by composite resin. However, still there are many unsolved problems, for example, technique sensitivity, polymerization shrinkage stress and limited mechanical properties. These factors results in fracture of the restoration and secondary caries of the tooth. Also the use of the dental bonding system should be used for the retention of the restoration. In this paper, I want to talk about the present and the future of the remineralizing component released from dental composite resin to overcome the secondary caries and there possibility in the clinical use.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.235-237
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• 2001

;Dentistry has benefited from tremendous advances in technology with the introduction of new techniques and materials, and patients are aware that esthetic approaches in dentistry can change one's appearance. Increasingly. tooth-colored restorative materials have been used for restoration of posterior teeth. Tooth-colored restoration for posterior teeth can be divided into three categories: 1) the direct techniques that can be made in a single appointment and are an intraoral procedure utilizing composites: 2) the semidirect techniques that require both an intraoral and an extraoral procedure and are luted chairside utilizing composites: and 3) the indirect techniques that require several appointments and the expertise of a dental technician working with either composites or ceramics. But, resin restoration has inherent drawbacks of microleakage. polymerization shrinkage, thermal cycling problems. and wear in stress-bearing areas. On the other hand, Ceramic restorations have many advantages over resin restorations. Ceramic inlays are reported to have less leakage than resin restoration and to fit better. although marginal fidelity depends on technique and is laboratory dependent. Adhesion of luting resin is more reliable and durable to etched ceramic material than to treated resin composite. In view of color matching, periodontal health. resistance to abrasion, ceramic restoration is superior to resin restorationl. Materials which have been used for the fabrication of ceramic restorations are various. Conventional powder slurry ceramics are also available. Castable ceramics are produced by centrifugal casting of heat-treated glass ceramics. and machinable ceramics are feldspathic porcelains or cast glass ceramics which are milled using a CAD/CAM apparatus to produce inlays (for example, Cered. They may also be copy milled using the Celay apparatus. Pressable ceramics are produced from feldspathic porcelain which is supplied in ingot form and heated and moulded under pressure to produce a restoration. Infiltrated ceramics are another class of material which are available for use as ceramic inlays. An example is $In-Ceram^{\circledR}$(Vident. California, USA) which consists of a porous aluminum oxide or spinell core infiltrated with glass and subsequently veneered with feldspathic porcelain. In the 1980s. the development of compatible refractory materials made fabrication easier. and the development of adhesive resin cements greatly improved clinical success rates. This case report presents esthetic ceramic inlays for posterior teeth.teeth.

• Restorative Dentistry and Endodontics
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• v.26 no.1
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• pp.16-22
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• 2001

The purpose of this study was to evaluate the marginal microleakage of condensable composite resin restorations according to flowable resin lining of internal cavity wall. The eighty extracted human molar teeth without caries and/or restorations are used The experimental teeth were randomly assigned into four groups of ten teeth each. Eighty caries-free extracted human molars were used in this study. The conventional class II cavities (box-shaped on mesial and distal surface, faciolingual width : 3mm, gingival wall depth : 1.5mm) were prepared 1mm below cementoenamel junction with a # 701 carbide bur. The teeth were divided into four groups, and then each group were subdivided into A & B group according to flowable resin & compomer lining ; Group 1-A : Tetric Ceram filling, Group 1-B : Tetric Flow lining and Tetric Ceram filling, Group 2-A Ariston pHc filling, Group 2-B : Tetric Flow lining and Ariston pHc filing, Group 3-A SureFil filling, Group 3-B : Dyract Flow lining and SureFil filling, Group 4-A : Pyramid filling, Group 4-B : Aeliteflo lining and Pyramid filling. To simulate as closely as possible the clinical situation during retoration placement, a "restoration template" was fabricated, and the condensable resin was filled using a three-sited light-curing incremental technique. All the materials used were applied according to the manufacturers' instructions. The specimens were stored in the 100% humidity for 7 days prior to thermocycling (100 thermal cycles of 5~55$^{\circ}C$ water with a 30-second dwell time) The specimens were immersed in 2% metyleneblue dye for 24 hours, and then embedded in transparent acrylic resin and sectioned mesiodistally with diamond wheel saw. The degree of marginal leakage was scored under stereomicroscope ($\times$20) and the data were analyzed by Kruskal-Wallis test and Wilcoxon signed ranks test. The results were as follows : 1. In the gingival margins of all the group, microleakage of subgroup B was less than subgroup A. 2. In the group 1, 2, 4, there was significant differences between subgroup A and B (p<0.05), but in the group 3, there was not significant different between group 3-A (SureFil) and group 3-B (Dyract flow/SureFil) (p>0.05). 3. In the subgroup A and B, there was significant different between all group except group 4 of subgroup A. From the results above, it was suggested that the cavity lining of flowable resin and flowable compomer in condensable resin restoration decrease microleakage at gingival margin, and does improve their ability to seal the gingival margin of class II preparation.

• Conservation Science in Museum
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• v.21
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• pp.1-16
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• 2019

This study investigated the material properties of UV-curable Resin in order to identify stable materials for use in the restoration of glass cultural properties. Tested samples were based on acrylic UV-curable Resin (SECURE CP-7321®), to which urethane UV-curable Resin (FLGPCL04 Clear®) was added in 10% increments to produce eleven samples. The results showed that all eleven samples had similar properties in terms of refractive index, density, adhesive strength, and anti-yellowing. But the surface hardness and compressive strength were optimal and effective for maintaining the shape of artifacts after restoration treatment when the proportion of urethane resin was in the range of 10-20%. Based on these findings, the mixing sample [acrylic UV-curable Resin(9) : urethane UV-curable Resin(1)] was applied in the conservation treatment of a glass cultural propertie (Hwangbuk 519) excavated from the North Mound of Hwangnamdaechong, Tomb in Gyeongju.

• Imaging Science in Dentistry
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• v.48 no.2
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• pp.87-96
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• 2018

Purpose: The present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT). Materials and Methods: Forty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient. Results: For bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations (P<.05). CBCT images exhibited good results for resin restorations(P>.05), but showed no discriminatory ability for amalgam restorations(P<.05). Conclusion: Bitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.255-261
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• 2002

The purpose of this study was to compare the microleakage pattern of flowable composite resin to sealant, composite resin used in preventive resin restoration and glass ionomer cement used as liner. 120 extracted sound human molars were divided into 6 groups : group 1 and 2:sealant ; group 3 and 4:preventive resin restoration ; group 5 and 6:sandwich technique restoration. For the experimental groups(group 2, 4 and 6), flowable composite resin(Tetric flow) was used. For the control group, Concise was used as sealant material(group 1), Z-100 with Concise were used as preventive resin restoration(group 3), and Vitrebond was used as cavity liner(group 5). All the restorations were thermocycled and the degree of dye penetration was evaluated with stereomicroscope. The microleakage of each group was measured and statistically analyzed. The results of the present study were as follows : 1. In group 1 and 2, there was no statistically significant difference in microleakage between Concise and Tetric flow(p>0.05). 2. In groups of preventive resin restorations, there was no statistically significant difference in microleakage between Z-100 with Concise and Tetric flow(p>0.05). 3. The microleakage of Vitrebond and Tetric flow used as liner showed no statistically significant difference(p>0.05).

• 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 academy of Pediatric Dentistry
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• v.28 no.3
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• pp.504-511
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• 2001

Preventive resin restoration, extended concept of occlusal pit and fissure sealing, is procedure composed of as follows. Cavity preparation is limited to areas of initial caries The cavity is then restored with composite resin, while other sound pits and fissures are sealed with pit and fissure sealant. If pit and assure sealant with which microrestoration is possible is used, it may be of great benefit to both patient and operator in case of difficult-to-control children s treatment. However study on preventive resin restoration using this kind of materials have been scarce. The purpose of this study was to compare the microleakage of four different modes of preventive resin restoration. Restoration using only composite resin was compared together Fifty-five bicuspids were prepared with small class I cavity preparation on the occlusal surface, divided into the following groups and restored accordingly. Group 1 : Cavity was restored with Z-100 composite resin Group 2 : Cavity was restored with Z-100 composite resin. Pits and fissures were then sealed with Teethmate F-1 Group 3 : Cavity was restored with Z-100 composite resin Pits and fissures were then sealed with Ultraseal XT-plus Group 4 : Cavity and pits and fissures were restored with Ultraseal XT-plus altogrether Group 5 : Cavity was restored with Ultraseal XT-plus. Pits and fissures were then sealed with the same material. After restoration, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue solution for 24 hours, then rinsed with tap water. The teeth were then embedded in resin and cut buccolingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage. The results were as follows : 1. Group 4 showed the greatest microleakage, while group 3, showed the least. The mean microleakage decreased in the following order:4>1>5>2>3. 2. There was no stastically significant difference between group 1 and group 5(p>0.05). However, group 1 showed significantly greater microleakage compared to group 2 and 3(p<0.05) Group 1 showed significantly less microleakage compared to group 4(p<0.05). 3. Group 2 showed no statistically significant difference compared to group 3(p>0.05). However group 2 showed significantly less microleakage compared to group 4 and 5(p<0.05) 4. Group 3 showed significantly less microleakage compared to group 4 and 5(p<0.05). 5. Group 5 showed significantly less microleakage than group 4(p<0.05).