• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.33-54
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• 1995

The degree of conversion of composite resin was known to have influence on the mechanical properties of composite materials such as hardness, strength, wear resisitance, dimensional and color stability. Also unreacted monomer was reported to be harmful to the pulp. So the degree of conversion was a very important factor in the success of composite resin restorations. In recent, the dual cure resin cement was developed with the advocations that it could increase the curing rates in the sites where the curing ligt could not reach. Moreover many manufactors added some adhesive components in the resin cement. This study was undertaken to observe the effects of curing depth and light curing times on the degree of conversion of dual cure resin cements. CR INLAY CEMENT, DUAL CEMENT and OPTEC BOND, by the Fourier transform Infrared analysis, changing the curing depth 1mm, 2mm and 3mm, and varying the light curing time 20 seconds, 40 seconds and 80 seconds at each depth. The cytotoxicity of dual cure resin cements was tested by the in vitro MTT method using L929 cell. The results was evaluated and compared statistically. The results were obtained as follows : 1. The dual cure resin cements reavealed various degree of conversion, CR INLAY CEMENT and DUAL CEMENT had a tendency to be more reactive to the light cure and OPTEC BOND was a more chemical one. 2. CR INLAY CEMENT and DUAL CEMENT showed the lowest degree of conversion in 2 mm depth, and in 3mm depth the degree of conversion increased, which were due to the chemical cure of dual cures, but OPTEC BOND showed decreasing degree of conversion with increasing curing dept h and all experimental groups showed lower degree of conversion than CHEMICAL group which cured in dark room with no light, so the weak light-curing of dual cure resin cement prevented the chemical cure. (P<0.05) 3. CR INLAY CEMENT and DUAL CEMENT showed increasing degree of conversion in 1 mm and 3 mm, according to the increasing cure times, but in 2 mm depth the degree of conversion decreased with increasing light-curing times and OPTEC BOND showed contrary tendency, but there was no ststistical importance in the differences among the experimental group.(P>0.05) 4. The optical density by MTT assay of extractions of CR INLAY CEMENT, DUAL CEMENT and OPTEC BOND revealed no statitically important differences comparing with optical density of negative control.(P>0.05) 5. CR INLAY CEMENT showed a tendency of increaing cytotoxicity with days and DUAL CEMENT and OPTEC BOND showed higher cytotoxicity in 2 days than in 4 days, but there was no statistical importance in the differences.(P>0.05).

• 구강회복응용과학지
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• 제26권3호
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• pp.311-322
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• 2010

본 연구는 최근 심미수복에 흔히 사용되는 IPS e.max Press와 각종 레진 시멘트간의 결합강도를 알아보고자 하였다. 직경 12mm, 높이 3mm의 원반형 IPS e.max Press 시편을 제조사의 지시에 따라 만들어 초음파로 세척하여 자가중합 아크릴릭 레진에 포매하였다. 플라스틱 튜브를 사용하여 직경 4.5mm, 높이 3mm의 40개의 원주형 레진 시편을 제작하였다. 각각의 시편은 무작위로 4개의 실험군으로 나뉘고 4 종류의 서로 다른 레진 시멘트(Variolink II(light-cure), Variolink II(dual-cure), Calibra, Super-Bond C&B)를 이용하여 제조사의 지시에 따라 부착하였다. 부착된 시편은 강도 측정 전에 $37^{\circ}C$ 에서 24시간 동안 생리식염수에 보관하였다. 만능시험기를 사용하여 1mm/min 의 crosshead speed로 각 시편에 힘을 가하여 전단결합강도를 측정하였다. 측정된 결합강도는 SPSS V12.0을 사용하여 일원배치 분산분석으로 비교 분석하였으며, 사후 검증은 Tukey HSD test를 이용하여 분석하였다. Super-Bond C&B의 전단결합강도는 Calibra, Variolink II(light-cure), Variolink II(dual-cure)에 비해 유의하게 낮은 값을 나타내었다(P<.01). Calibra, Variolink II(light-cure), Variolink II(dual-cure)는 전단결합강도에서 서로 유의한 차이를 보이지 않았다. 광중합형과 이원 중합형 레진 시멘트의 전단결합강도는 자가 중합형 시멘트보다 높았다.

• 대한소아치과학회지
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• 제23권4호
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• pp.906-914
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• 1996

Due to the various reason, sealing of pit & fissure might be imperfect. One of these reason can be the fracture of sealant material because of the low hardness value of sealing material. The purpose of this in vitro study was to evaluate the microhardness of two different curing type pit and fissure sealants: Dual-cure and Light-cure. The result from the present study can be summarized as follows: 1. All pit and fissure sealants that used in this study showed statistically significant difference in their microhardness of upper and lower surface. (P <0.05) 2. Except of lower surface of teethmate, microhardness of 40-second curing sealant was statistically higher than that of 20-second curing sealant. (P <0.05) 3. In comparison of sealants, microhardness of dual-cure sealant was statistically higher than that of light-cure sealant. Above results suggest that the use of dual-cure sealant and longer curing time are recommended.

• Restorative Dentistry and Endodontics
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• 제36권2호
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• pp.132-138
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• 2011

연구목적: 본 연구는 3종의 이중중합 레진시멘트에서 자가중합법과 이중중합법이 중합도에 미치는 영향을 간접적으로 알아보고자 시간경과에 따라 미세경도를 측정하였다. 연구 재료 및 방법: 실험을 위해 자가접착 레진시멘트인 Maxcem Elite (Kerr)와 Rely-X Unicem (3M ESPE) 및 전통형 레진시멘트인 Rely-X ARC (3M ESPE)를 사용하였으며 각 레진시멘트를 동일한 크기의 테플론 몰드에 채우고 자가중합법과 이중중합법으로 중합을 하여 각각 10개씩 시편을 제작하였으며 중합 시작 후 10분, 30분, 1시간, 3시간, 6시간, 12시간, 24시간이 지난 시점에 미세경도를 측정하였다. 결과: 각 시점에서 레진시멘트별로 중합법 사이의 비교를 위한 independent samples t-test 및 모든 실험군 사이의 비교를 위한 one-way ANOVA와 Scheffe 사후검정을 95% 유의수준에서 실시하여 다음과 같은 결과를 얻었다. 1. 모든 실험군에서 시간이 경과함에 따라 미세경도가 증가하는 경향을 보였다. 2. Maxcem에서 중합 1시간 후 부터를 제외하고 이중중합이 자가중합에 비해 높은 미세경도 값을 보였다(p<0.05). 3. 매 시점에서 자가중합법의 Rely-X Unicem이 가장 낮은 미세경도를 보였으며 이중중합법의 Rely-X Unicem이 가장 높은 미세경도 값을 보였다. 결론: 이상의 실험 결과로 볼 때 이중중합 레진시멘트의 충분한 중합을 위해서는 광조사를 반드시 하여야 할 것으로 생각한다.

• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.265-285
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• 1999

The purposes of this investigation were to observe the reaction kinetics of five commercial dual cured resin cements (Bistite, Dual, Scotchbond, Duolink and Duo) when cured under varying thicknesses of porcelain inlays by chemical or light activation and to evaluate the effect of the porcelain disc on the rate of polymerization of dual cured resin cement during light exposure by using thermal analysis. Thermogravimetric analysis(TGA) was used to evaluate the weight change as a function of temperature during a thermal program from $25{\sim}800^{\circ}C$ at rate of $10^{\circ}C$/min and to measure inorganic filler weight %. Differential scanning calorimetry(DSC) was used to evaluate the heat of cure(${\Delta}H$), maximum rate of heat output and peak heat flow time in dual cured resin cement systems when the polymerization reaction occured by chemical cure only or by light exposure through 0mm, 1mm, 2mm and 4mm thickness of porcelain discs. In 4mm thickness of porcelain disc, the exposure time was varied from 40s to 60s to investigate the effect of the exposure time on polymerization reaction. To investigate the effect on the setting of dual cured resin cements of absorption of polymerizing light by porcelain materials used as inlays and onlays, the change of the intensity of the light attenuated by 1mm, 2mm and 4mm thickness of porcelain discs was measured using curing radiometer. The results were as follows 1. The heat of cure of resin cements was 34~60J/gm and significant differences were observed between brands (P<0.001). Inverse relationship was present between the heat of reaction and filler weight % the heat of cure decreased with increasing filler content (R=-0.967). The heat of reaction by light cure was greater than by chemical cure in Bistite, Scotchbond and Duolink(P<0.05), but there was no statistically significant difference in Dual and Duo(P>0.05). 2. The polymerization rate of chemical cure and light cure of five commercially available dual cured resin cements was found to vary greatly with brand. Setting time based on peak heat flow time was shortest in Duo during chemical cure, and shortest in Dual during light cure. Cure speed by light exposure was 5~20 times faster than by chemical cure in dual cured resin cements. The dual cured resin cements differed markedly in the ratio of light and chemical activated catalysts. 3. The peak heat flow time increased by 1.51, 1.87, and 3.24 times as light cure was done through 1mm, 2mm and 4mm thick porcelain discs. Exposure times recommended by the manufacturers were insufficient to compensate for the attenuation of light by the 4mm thick porcelain disc. 4. A strong inverse relationship was observed between peak heat flow and peak time in chemical cure(R=0.951), and a strong positive correlations hip was observed between peak heat flow and the heat of cure in light cure(R=0.928). There was no correlationship present between filler weight % or heat of cure and peak time. 5. The thermal decomposition of resin cements occured primarily between $300^{\circ}C$ and $480^{\circ}C$ with maximum decomposition rates at $335^{\circ}C$ and $440^{\circ}C$.

• International Journal of Oral Biology
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• 제46권4호
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• pp.184-189
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• 2021

When luting indirect restorations with dual-cure resin cement (DCRC), excess cement can be easily removed by performing tack cure of DCRC for a few seconds. The purpose of this study was to evaluate whether different tack cure times affect polymerization shrinkage (PS) of the selected DCRC. One dual-cure resin cement (G-CEM LinkAce, GC) was used for measuring PS in light-cure (LC group), self-cure (SC group), and two tack-cure modes. In the first tack-cure subgroup, tack cure was performed for 1, 2, 3, and 5 seconds, followed by light cure after 2 minutes of remnant removal time in each case (TC-LC groups). In the other tack-cure subgroup, tack cure was performed for the same lengths of time, but followed by self-cure in each case (TC-SC groups). PS was measured by a modified bonded disc method for 1,800 seconds. One-way analysis of variance followed by Duncan's post hoc test was used to determine any statistically significant differences among the test groups (α = 0.05). When the DCRC was self-cured after tack cure, PS was significantly lower than when it was only self-cured (p < 0.05); however, tack cure time did not affect PS (p > 0.05). When the DCRC was light-cured, PS was not affected by tack cure or tack cure time (p > 0.05). Therefore, tack cure within 5 seconds did not negatively affect the final PS when the DCRC was light-cured after cement remnant removal.

• 대한소아치과학회지
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• 제26권3호
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• pp.554-563
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• 1999

심미적 수복재료인 복합 레진과 글래스 아이오노머 시멘트는 중합방식에 따라 화학중합형, 광중합형, 그리고 이 두 가지 중합방식을 겸비한 이중중합형으로 분류할 수 있다. 화학중합형과 광중합형에 대해서는 지금까지 다수의 보고가 있었으나, 충전용 복합 레진의 경우 이들과 이중중합형을 비교한 예는 아직 찾기 힘든 실정이었으므로, 이러한 관점에서의 연구가 필요할 것으로 사료되었다. 이 연구에서는 이중중합 수복재가 단일중합방식에 비해 어떠한 특성을 보이는지를 탐구하고자 하였다. 사용된 재료는 광중합형 복합 레진인 Veridonfil-Photo와 이중중합형인 Bis-core, 이중중합형의 글래스 아이오노머 시멘트인 Fuji II LC와 화학중합형인 Ketac-fil을 사용하였다. 가로 30mm, 세로 30mm, 높이 1mm와 3mm인 두 종류의 아크릴릭 몰드 중앙에 직경 7mm의 hole을 형성하여 여기에 4종의 수복재를 충전하였다. 충전 직후부터 시작하여 24시간 경과시까지 일정 시간의 간격으로 표면, 1mm, 3mm 깊이에서의 경도를 미세경도계(Shimadzu Micro Hardness Tester HMV-2000, Shimadzu Co. Japan)로 측정하였다. 측정치를 통계처리하여 얻은 결과는 다음과 같다. 1. 4 종의 수복재 모두에서, 중합직후에 비해 24시간 경과후의 미세경도가 증가되었다. 2. 중합 직후부터 24시간 경과시점까지의 미세경도를 측정한 결과, Ketac-fil을 제외한 나머지 수복재에서는 각 깊이간 경도의 차이가 있었다. 3. 각 수복제의 최종중합에 도달하는 시간을 조사한 결과, 이중중합형이 3min의 깊이에서 광중합형이나 화학중합형에 비해 중합이 더 오래 지속된 것으로 나타났다. 이상의 결과에서 조사광이 충분히 도달하지 못하여 중합이 현저히 떨어지는 수복재의 심부에도 이중중합방식을 사용할 경우에는 지속적인 중합반응이 일어나 중합도가 증가하는 것으로 나타났다.

• Restorative Dentistry and Endodontics
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• 제31권5호
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• pp.352-358
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• 2006

본 연구는 코어용 이중 중합 레진의 중합도에 미치는 두께의 영향과 빛이 감소된 깊은 와동에서 자가 중합에 의한 영향을 조사하고자 하였다. Luxacore Dual과 Luxacore Self (DMG Inc, Hamburg, Germany) 두 종류의 코어용 레진 수복재를 지름 10 mm, 두께가 2, 4, 6, 8 mm 의 Teflon mold에 주입하고 자가중합 시키거나 혹은 $500 mW/cm^2$의 광도로 제조자의 지시에 따라 중합 후 $37^{\circ}C$ 증류수에 24시간동안 저장하였다. 각 시편의 윗면과 아랫면에서 Knoop's hardness를 측정하였다. 결과는 ANOVA로 통계 분석 하였고 Tukey's test로 사후 검정하였다. Luxacore Self와 Luxacore Dual을 자가중합 시킨 군의 중합도는 두께에 따른 영향을 받지 않았다. Luxacore dual을 광중합한 경우 중합은 2 mm, 4 mm와 6 (적층충전) mm군에서는 밑면의 효과적인 중합이 일어났으나 8 (적층충전) mm군, 6, 8 (단일충전) mm군은 밑면에서 불완전한 중합을 보였다 (p < 0.05). 따라서 이 실험 결과에 의하면 4 mm를 초과하는 경우 단일충전보다 적층충전이 더 좋은 것으로 나타났다.

• The Journal of Advanced Prosthodontics
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• 제14권2호
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• pp.78-87
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• 2022

PURPOSE. This study aimed to compare the effect of different surface treatments and luting agent types on the shear bond strength of two ceramics to commercially pure titanium (Cp Ti). MATERIALS AND METHODS. A total of 160 Cp Ti specimens were divided into 4 subgroups (n = 40) according to surface treatments received (control, 50 ㎛ airborne-particle abrasion, 110 ㎛ airborne-particle abrasion, and tribochemical coating). The cementation surfaces of titanium and all-ceramic specimens were treated with a universal primer. Two cubic all-ceramic discs (lithium disilicate ceramic (LDC) and zirconia-reinforced lithium silicate ceramic (ZLC)) were cemented to titanium using two types of resin-based luting agents: self-cure and dual-cure (n = 10). After cementation, all specimens were subjected to 5000 cycles of thermal aging. A shear bond strength (SBS) test was conducted, and the failure mode was determined using a scanning electron microscope. Data were analyzed using three-way ANOVA, and the Tukey-HSD test was used for post hoc comparisons (P < .05). RESULTS. Significant differences were found among the groups based on surface treatment, resin-based luting agent, and ceramic type (P < .05). Among the surface treatments, 50 ㎛ air-abrasion showed the highest SBS, while the control group showed the lowest. SBS was higher for dual-cure resin-based luting agent than self-cure luting agent. ZLC showed better SBS values than LDC. CONCLUSION. The cementation of ZLC with dual-cure resin-based luting agent showed better bonding effectiveness to commercially pure titanium treated with 50 ㎛ airborne-particle abrasion.

• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.291-299
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• 2018

PURPOSE. To assess the degree of conversion (DC) and light irradiance delivered to light-cured and dual-cured cements by application of different light sources through various types of monolithic computer-aided design and computer-aided manufacturing (CAD/CAM) materials. MATERIALS AND METHODS. RelyX Ultimate Clicker light-cured and dual-cured resin cement specimens with 1.5-mm thicknesses (n=300, 10/group), were placed under four types of crystalline core structure (Vita Enamic, Vita Suprinity, GC Ceresmart, Degudent Prettau Anterior). The specimens were irradiated for 40 seconds with an LED Soft-Start or pulse-delay unit or 20 seconds with a QTH unit. DC ratios were determined by using Fourier transform infrared spectroscopy (FTIR) after curing the specimen at 1 day and 1 month. The data were analyzed using the Mann-Whitney U test (for paired comparison) and the Kruskal-Wallis H test (for multiple comparison), with a significance level of P<.05. RESULTS. DC values were the highest for RelyX Ultimate Clicker light-cure specimens polymerized with the LED Soft-Start unit. The combination of the Vita Suprinity disc and RelyX Ultimate Clicker dual-cure resin cement yielded significantly higher values at both timepoints with all light units (all, P<.05). CONCLUSION. Within the limitations of this study, we conclude that the DC of RelyX Ultimate Clicker dual-cure resin cement was improved significantly by the use of Vita Suprinity and the LED Soft-Start light unit. We strongly recommend the combined use of an LED light unit and dual-cure luting cement for monolithic ceramic restorations.