• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.129-141
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• 1995

Composite resin and glass-ionomer cement can be used for the purpose of repair of defective amalgam restoration. The purpose of this study was to evaluate of shear bond strength of esthetic restorative materials to dental amalgam. The materials used in this study were Photo Clearfil Bright(light curing composite resin), Clearfil F II(chemical curing composite resin), Fuji II LC(light curing glass-ionomer cement), Fuji II (chemical curing glass-ionomer cement), All-Bond 2(intermediary), and Scotchbond Multi-Purpose (intermediary). A total of 120 acrylic cylinders with amalgam were divided into 8 groups After amalgam condensation, all specimens were stored for 48 hours in water at $37^{\circ}C$ and tested with Instron universal testing machine between amalgam and composite resins and glass-ionomer cements. The data were analyzes statiscally by ANOVA and Duncan test. The following results obtained ; 1. The shear bond strength of bonded composite resin to amalgam was higher than bonded glass-ionomer cement(P<.001). 2. The group 4 had highest shear bond strength with 15.45kgf/$cm^2$ and the group 5 had lowest shear bond strenght with 3.26kgf/$cm^2$(P<.001). 3. In the group 3, 4, 5, 6, the group 3, 4 with All-Bond 2 had higher shear bond strength than the group 5, 6 with Scotch bond MP both in light-curing and in chemical curing. 4. Both in composite resin and glass-ionomer cement, chemical curing materials had higher shear bond stength than light curing materials(P<.001).

• 대한소아치과학회지
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• 제31권2호
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• pp.273-279
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• 2004

최근에 소개된 single high-intensity LED 중합기는 이전의 LED 중합기에 비해 높은 광도를 가지며 짧은 중합시간에 적절한 물성을 가질 수 있다고 한다. 본 연구는 single high-intensity LED 중합기의 중합성능을 평가하기 위하여 거리에 따른 중합도를 조사하였다. Mylar strip사이에 복합레진(Filtek Z250)을 넣고 압접시켜 만든 얇은 필름형 시편을 LED 중합기(Elipar Freelight 2, 10초), 플라스마 중합기(Flipo, 6초)와 할로겐 중합기 (XL3000, 20초)를 사용해 0mm, 2mm, 4mm, 6mm에서 광도를 측정하고 중합시켰다. 중합된 시편을 Fourier Transform Infrared Spectrometer(FTIR)를 이용해 중합도를 측정한 후 다음과 같은 결론을 얻었다. 1. 모든 중합기에서 거리가 증가할수록 유의하게 광도가 감소하였으며 LED중합기의 경우 6mm에서 다른 중합기에 비해 가장 많은 광도 감소율을 보였다(p<0.05). 2. 모든 중합기에서 거리가 증가함에 따라 4mm까지는 중합도가 감소하였지만 유의한 차이는 보이지 않았다(p>0.05). 하지만 4mm와 6mm사이에서는 모든 중합기에서 유의하게 감소하였다(p<0.05). 3. 각 거리에 따른 중합기간의 중합도 차이는 0mm, 2mm, 4 mm에서 LED중합기가 다른 중합기보다 유의하게 높은 중합도를 보였으며 (p<0.05) 플라스마 중합기와 할로겐 중합기 사이에서는 유의한 차이가 없었다. 하지만 6 mm에서는 모든 중합기 사이에 유의한 차이를 보이지 않았다(p>0.05).

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.360-365
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• 1996

The purpose of this study was to evaluate the changes in the degree of conversion on a composite resin surface following heat treatment and mylar strip finishing. The effects of the time interval between the light-curing and heat-curing process were also evaluated. The composite resin surface which had been covered with a coverglass showed a lower conversion rate than the surface from which a layer of $500{\mu}m$ was ground away. The composite resin surface was definitely affected by oxygen during the heat curing process when it had not been insulated. When the composite resins were heat cured after 3 days of storage following the light curing process, the increased in the degree of conversion through heatcuring was limited.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.487-507
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• 1995

Composite resin repair requires strong bond strength between the new and old materials. The objective of the current study was to identify the optimal treatments for sufficient bond strengths. Bondings between same kinds of materials and cross bondings using chemical curing composites and light curing composites were tested. Surface treatments included the methods of sand-blasting, acid etching and coating of bonding agent. Seven kinds cases of combinations from three kinds of methods were experimented and compared with a control group of which surfaces were highly polished. Measurements of shear bond strength and observations of surface morphologic changes using a scanning electron microscope were done. Following conclusions were drawn : 1. The highest bond strength among composite resins were exhibited by the treatment of the sand-blasting and the coating of bonding agent. 2. Acid etched surfaces showed the lowest bond strength. Bond strengths obtained from experimental groups including acid etching were lower than those obtained from same kinds of experimental groups without acid etching. 3. Simple method of the coating of bonding agent produced the slightly increased bond strength on chemical curing composite and reduced bond strength on light curing composite. 4. Bonding surfaces of chemical curing composite resin showed slightly higher bond strengths than light curing composite resin, however significant differences were not confirmed statistically. 5. More significant irregular surfaces were created by sand-blasting method than acid etching method. 6. A principal component of fillers of both resins was silicon. Acid etching method produced the seperations and degradations of fillers, these were significant on light curing composite resins which containing barium fillers.

• 대한치과기공학회지
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• 제29권2호
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• pp.9-15
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• 2007

As the development of nanotechnology, the use of composite resins which containing nanofillers becomes popular. The purpose of this study was to test the degree of polymerization of nanofillercontaining composite resins. For the study, three different nanofiller-containing composite resins and two different light-curing units were used. To evaluate the degree of polymerization, the maximum polymerization shrinkage taking place during the light curing, and the microhardness, after the light curing, were measured. As results, two light-curing units exhibited a similar emission spectrum to that of the included photoinitiator, camphorquinone. The only difference between the light-curing units were the width of the emission spectrum. Three different composite resins showed different microhardness values. Among them, Grandio showed the greatest microhardness value. However, there was less microhardness difference on the top and bottom surfaces due to the difference of the light-curing units. The maximum polymerization shrinkage values were also similar in the tested specimens regardless of the difference of the light-curing units. However, Grandio showed the least polymerization shrinkage. According to the manufacturers' data, Grandio showed the highest filler content(vol%).

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.158-166
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• 1991

In order to investigate the cytotoxicity of composite resin in vitro, BALB / C mouse fibroblast were cultured in MEM in which silux, P-50, microrest, clearfil, amalgam and glass - ionomer, in shape of $2{\times}9mm$ circular disk. The experiments were- performed by cell count on 4 hours, 1, 3, 6 days and the composite resin groups, amalgam, glass - ionomer were compared. 1. On the sixth day, the cellular number of resin composite groups were remarkedly reduced, in contrast, the that of amalgam and glass - ionomer group continuously increased. 2. It was only on the 4 hours that the cellular number contained in amalgam were reduced, but increased thereafter, and the cellular number contained in glass - ionomer are greater than other groups. 3. In resin group, especially between self - curing resin and light - curing resin, there is no difference in cellular number statistically (p>0.05). 4. It was amalgam where the round cell without cellular process was found on the 4. hours and on the 6 th day the cell without cellular process was found numeroulsy in resin group whereas in amalgam and glass - ionomer, like control group was contained cell forming monolayer. These result suggested that the toxicity of the self - curing and light - curing resin greater than that of the amalgam and glass - ionomer.

• 대한소아치과학회지
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• 제30권4호
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• pp.593-599
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• 2003

치과의 수복재로 널리 쓰이는 복합레진의 미세누출에 대한 할로겐광과 플라즈마광의 영향을 비교하고, 유동성 복합레진과 할로겐광으로도 중합시간이 20초로 단축된 복합레진 $Filtek^{TM}$ Z250이 미세누출면에서 기존에 널리 쓰이던 복합레진인 Z100을 대체할 수 있을지를 평가하며, 미세누출에 미치는 adhesive resin의 영향을 알아보고자 본 실험을 수행하였다. 발거된 치아에 5급 와동을 형성하고 레진의 충전은 각 군에 따라 시행하였다. 유동성복합레진 $Filtek^{TM}Flow$와 Z100, $Filtek^{TM}Z250$을 이용하였고, 할로겐광과 플라즈마광을 이용하여 중합하였다 충전이 완료된 시편은 보관, 연마, 열순환을 시행하고, 1% methylene blue를 침투시킨 후 협설로 절단하여 미세누출 정도를 관찰하여 다음과 같은 결론을 얻었다. 1. $Filtek^{TM}Flow$와 $Filtek^{TM}Z250$ 모두 광원에 따른 미세누출의 차이는 없었다(p>0.05). 2. 유동성 복합레진인 $Filtek^{TM}Flow$는 복합레진 $Filtek^{TM}Z250$과 Z100에 비해 통계적으로 유의성있는 큰 미세누출을 보여(p<0.05) 유동성 복합레진만으로 수복한다면 미세누출의 위험이 커질 것이다. 3. Adhesive resin을 도포한 것이 할로겐광을 이용한 경우와 플라즈마광을 이용한 경우 모두에서 통계적으로 유의하게 미세누출을 감소시켰다.(p<0.05)

• 대한소아치과학회지
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• 제25권4호
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• pp.731-748
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• 1998

The purpose of this study was to test the hypothesis that the more thorough cure of lightactivated composite resin could be obtained if a new way of delivering the light source deep through the resin body is developed when compared to the conventional bulk cure or incremental cure. Using cylindrical resin blocks and natural teeth, various curing conditions were tested for their effects on the degree of microleakage and microhardness. Data were analyzed statistically using One-Way ANOVA and Scheff's Multiple Range test. The results of the present study were as follows: 1. The increment of reduction in microhardness with depth was shown to be higher in group I and II than in group II and V. 2. At the level of lower inner surface and the bottom surface, significantly lower microhardness values were obtained in group I and II when compared to group III, IV and V. Group IV showed the lowest value among three groups(III, IV, V) representing the only statistically significant difference from group V(p<05). 3. Differences between groups in the degree of microleakage detected were shown to be statistically significant (p<05) with the exception of group IV and V at both occlusal and gingival margins. 4. Based upon the above-mentioned results, commonly cited recommendation of incremental curing is strongly supported and the light-transmitting wedge insertion method can be considered as a effective and feasible clinical procedure for the better curing of composite resin. However, more studies under a variety of conditions should be completed before this method is applied actually to the clinical setting.

• 대한소아치과학회지
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• 제30권2호
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• pp.245-253
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• 2003

치과용 복합레진의 중합률은 레진 기질내의 이중결합의 전환도를 나타내는 것으로 이는 재료의 물리적 성질과 기계적 성질 및 생체 친화성에 영향을 미친다. 레진의 중합도가 증가하면 취성과 수축이 증가하고 중합도가 낮으면 기계적 물리적 성질이 감소한다. 따라서 본 연구에서는 광중합형 복합레진을 사용하여 플라즈마 아크 중합기 2종, 할로겐 중합기 2종, LED 중합기 2종, pulse-delay curing의 서로 다른 중합방법의 경우를 FTIR 분석법으로 복합레진의 물리적 기계적 성질 및 생체친화성에 영향을 미치는 중합률을 분석하여 다음과 같은 결과를 얻었다. 1. 광중합 복합레진의 중합률은 FTIR로 측정하였을 때 34.52-49.31%사이로 나타났으며 플라즈마 아크 중합의 경우 Flipo는 $39.96{\pm}1.22%$, CrediII는 $45.64{\pm}1.34%$로, 할로겐 중합시 XL3000은 $43.48{\pm}1.34%$, VIP의 mode 4 사용시는 $44.31{\pm}0.72%$, LED의 LUXOMAX는 $49.31{\pm}2.37%$, Elipar Freelight는 $44.51{\pm}0.62%$, pulse-delay curing시에는 $34.52{\pm}0.85%$로 나타났다. 2. 각 중합 방법별로 중합률은 LED 중합 방법을 이용한 LUXOMAX가 다른 실험군에 비하여 가장 높은 중합률을 나타냈으며 pulse-delay curing 방법이 가장 낮은 중합률을 보였다. 3. Flipo 중합기, LUXOMAX 중합기, pulse-delay curing 방법이 다른 중합기와 비교하여 통계적으로 유의한 차이를 보였다(p<0.05). 4. 각 중합방법이 동일한 군 내의 중합기기별 차이에서는 할로겐에서는 광중합기 사이에 중합률의 차이를 보이지 않았으나 플라즈마 아크에서는 CrediII가, LED에서는 LUXOMAX가 중합률이 높았다(p<0.05).

• Restorative Dentistry and Endodontics
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• 제29권1호
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• pp.58-67
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• 2004

The objectives of this study was to evaluate current visible light curing units regarding microhardness and microleakage. Fourty samples of composite resin(Z-250, 3M) were cured by different light curing units (Flipo, LOKKI; Credi II, 3M; XL 3000, 3M: Optilux 500, Demetron) in acrylic blocks. Microhardness was measured using a calibrated Vickers indenter on both top and bottom surfaces after 24 hours of storage in air at room temperature. Class V cavities were prepared on buccal and lingual surfaces of fourty extracted human molars. Each margin was on enamel and dentin/cementum. Composite resin(Z-250, 3M) was filled in cavities and cured by four different light curing units (Flipo, LOKKl; Credi II, 3M; XL 3000, 3M: Optilux 500, Demetron). The results of this syudy were as follows: Microhardness 1. Flipo showed low microhardness compared to Optilux 500, Credi II significantly in upper surface. Flipo didn't show a significant difference compared to XL 3000. 2. The microhardness resulting from curing with Flipo was lower than that of others on lower surfaces. Microleakage 1. Dentin margin showed significantly high dye penetration rate than enamel margin in all groups(p<0.05). 2. No significant differences were found on both enamel and dentin margin regarding curing units.