HalogenIamp 광조사기와 Plasma xenon arc lamp 광조사기에 의한 광중합 복합레진의 중합률 비교

이영준,정병초,최남기,양규호 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.3

본 연구의 목적은 일반 halogen lamp 광조사기와 비교하여 plasma xenon arc lamp 광조사기의 광중합 능력을 평가하기 위한 것이다. 7mm의 내경과 1mm, 2mm, 3mm 두께를 갖는 레진 시편을 aluminum 주형상에서 제작하여 plasma xenon arc lamp 광조사기는 2초, 3초, 6초, halogen lamp 광조사기는 20초, 40초, 60초 동안 광조사한 후 Raman spectroscopy를 이용하여 레진 시편 표면과 후면의 중합률을 측정하였다. 표면 중합률은 광조사 시간이 증가함에 따라 halogen lamp 광조사기와 plasma xenon arc lamp 광조사기 모두에서 유의성있게 증가하였으며 전반적인 중합률은 halogen lamp 광조사기에서 더 높았으나 plasma xenon arc lamp 광조사기와 유의한 차이는 없었다. 광조사 시간이 증가함에 따라 halogen lamp 광조사기의 경우 후면 중합률은 모든 두께에서 점차 증가하였으나 1.2mm 두께에서는 유의한 차이가 없었으며 plas-ma xenon arc lamp 광조사기로 중합한 경우에는 모든 두께에서 조사시간이 증가할수록 중합률은 유의성있게 증가하였다. 이상의 결과로 plasma xenon arc lamp 광조사기의 강한 광도가 광조사 시간의 감소를 완전히 보상하지는 못하는 것으로 판단되므로 plasma xenon arc lamp 광조사기로 광중합 복합레진을 중합할 경우 2mm이내의 적층 충전이 요구되며 또한 제조회사가 제시한 조사 시간보다 추가적인 광조사가 필요할 것으로 판단된다. Recently, new light curing unit utilizing the plasma xenon arc lamp is introduced. This curing unit is operated at relatively high intensity, so shortening the curing time significantly. The aim of this experiment was to esti-mate curing capability of plasma xenon arc lamp curing unit compared to traditional halogen lamp curing unit. Degree of conversion was evaluated by Raman spectroscopy after irradiation of specimens with halogen lamp curing unit(Optilux 150, Demetron, USA) for 20s, 40s, 60s and plasma xenon arc lamp curing unit(flipo, Lokki, France) for 2s, 3s, 6s. The results showed that strong light intensity of plasma xenon arc lamp curing unit did not compensate for short exposure time completely. So, Multi-layered curing within 2mm thickness and addi-tional exposure time is recommanded when light-cured composite resin is polymerized with plasma xenon arc lamp curing unit.

LED와플라즈마 광원의 완속기시 광중합 방식이 복합레진의 수축응력에 미치는 영향

정양석,이난영,이상호 大韓小兒齒科學會 2007 大韓小兒齒科學會誌 Vol.34 No.4

본 연구는 LED와 플라즈마 광원의 복합레진의 중합시 완속기시 중합방식(soft-start curing)이 수축응력에 미치는 효과를 비교,평가하고자 하였다. 할로겐 광원으로 40초간 조사하여 복합레진을 중합한 경우와 LED와 플라즈마 광원의 단일광도 중합방식과 완속기시 중합방식으로 할로겐 40초 동안의 광에너지와 총량이 동일하도록 조사시간을 설정하였고 수축응력은 스트레인 게이지(Strain gauge)를 사용하여 측정하였다. 발생되는 수축응력을 비교,분석 및 평가한 결과 다음과 같은 결론을 얻었다. 1. 모든 군에서 중합 후 200초까지 수축응력이 급격하게 증가하였으나 이후 마지막 측정시간인 800초까지 완만한 증가를 보였다(P<O.05l). 2. LED와 플라즈마 광원의 완속기시 중합방법이 단일광도 중합방법에 비해 수축응력이 낮게 나타났다(P<O.05). 3. 할로겐 광원과 LED와 플라즈마 광원의 완속기시 중합의 수축응력 비교에는 유의차가 없었다(P>O.05). 완속기시 중합 방식을 사용할 경우 단일광도 중합 방식보다 수축응력을 감소시킬 수 있어 임상적으로 고광도 광원인 LED와 플라즈마 광원의 경우 완속기시 중합 방식의 사용이 유리하다고 보여진다. 그러나 완속기시 중합시 불충분한 중합을 방지하기 위해서는 완속기시를 보완하는 추가적인 중합시간이 요구될 것으로 사료된다. Effect of Soft-start curing on the contraction stress of composite resin restoration polymerized with LED and plasma curing unit. The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin (Filtek Z-250™, 3M ESPE, USA) was cured using the one-step continuous curing method with three difference light sources ; conventional halogen light (XL3000™), 3M ESPE, USA) cure for 40 seconds at 400 mw/cm², LED light (Elipar Freelight 2™. 3M-ESPE, USA) cure for 20 seconds at 800 mW/cm² a and plasma are light (Flipo™, LOKKI, France) cure for 12 seconds at 1300 mW/cm². For the soft-start curing method : LED light (Elipar Freelight 2™, 3M-ESPE, USA) cure exponential increase with 5 seconds followed by 17 seconds at 800 mW/cm² and plasma arc light (Flipo™, LOKKI. France) cure 2 seconds light exposure at 650 mW/cm² followed by 11 seconds at 1300 mW/cm². The strain guage method was used for determination of polymerization contraction. Measurements were recorded at each 2 second for the total of 800 seconds including the periods of light application. Obtained data were analyzed statically using Repeated measures ANOVA, One way ANOVA, and Tukey test. The results of present study can be summarized as follows: 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05). 2. Contraction stress was not revealed significant difference between Halogen curing light groups and LED and Plasma Light curing with soft-start group (P>0.05). 3. LED and Plasma Light curing with soft-start showed lower contraction stress than the one-step continuous light curing (P<0.05).

LED 광중합기의 조사 mode가 복합레진의 미세경도 및 수축응력에 미치는 영향

박인호,오유향,이난영,이창섭,이상호 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.2

이 연구의 목적은 LED 광중합기(Elipar Freelight 2?, 3M-ESPE, USA)의 조사 mode에 따른 복합레진(Supreme?, Filtek Flow?, 3M-ESPE USA)의 수축응력과 미세경도를 평가하는 것이다. 수축응력을 측정하기 위해 스트레인 게이지가 사용되었다. 표본은 조사 mode와 충전방법에 따라 6개의 군으로 나누어졌다. A군: Filtek Flow?이장, Supreme? 충전, 10초 광중합, B군: Filtek Flow?이장, Supreme? 충전, 15초 광중합, C군: Filtek Flow?이장, Supreme?충전, 15초 soft start 광중합, D군 Supreme? 충전, 10초 광중합, E군: Supreme?충전, 15초 광중합, F군: Supreme?충전, 15초 soft start광중합. 스트레인 게이지를 아크릴릭 링에 부착하고 strain meter에 연결한 후 광중합하고 10분 동안 1초 간격으로 측정하고 기록하였다. 24시간 후에 각각 표본의 미세경도를 측정하였다. 결과는 ANOVA와 Tukey test를 이용해 통계학적으로 분석하였다. 결과는 다음과 같았다. 1. Soft start curing 했을 때 수축응력 이 낮았다(p<0.05). Flow able resin을 이장한 군에서는 효과가 없었다. 2. 10초간 조사한 군은 15초간 조사한 군에 비해 수축응력이 적었다(p<0.05) 3. 미세경도 측정결과 상면과 하면에서 각 군 간에 차이는 없었다(p>0.05). 하지만, 하면의 미세경도가 상면에 비해 80%에 이르지 못했다. The purpose of this study was to evaluate the polymerization contraction and the micro hardness of composite resin(Supreme?, Filtek Flow?, 3M-ESPE, USA) according to irradiation modes of LED curing unit(Elipar Freelight?, 3M-ESPE, USA). The strain guage method was used for determination of polymerization contraction. Sample were divided by 6 groups according to curing modes and filling method. Group A: Supreme?, Filtek Flow? lining, 10seconds curing, Group B: Supreme?, Filtek Flow? lining, 15seconds curing, Group C: Supreme?, Filtek Flow? lining, 15seconds soft start curing, Group D: Supreme? only, 10seconds curing, Group E: Supreme? only, 15seconds curing, Group F: Supreme? only, 15seconds soft start curing Preparations of acrylic molds were followed by filling and curing. Strain guage attached to each sample were connected to a strain meter. Measurements were recorded at each second for the total of 10 minutes including the periods of light application. And micro hardness of each group after 24hours from light irradiation were measured. Obtained data were analyzed statistically using Repeated measures ANOVA and Tukey test. The results of the present study are as follows: 1. In flow able resin liner group, soft start curing group was not found decrease of polymerization contraction. But, In Supreme only filling group, the lowest polymerization contraction was found in soft start curing group. 2. 10 seconds curing group showed statistically significant reduction of polymerization contraction compared with 15 seconds curing group(p<0.05). 3. The micro hardness values of each group not revealed significant difference(p>0.05). But, lower surface micro hardness was not reached 80% of upper surface micro hardness.

유구치 I급 와동에서 와동벽 위치와 중합광원에 따른 Microtensile Bond Strength 비교 연구

이현헌,장철호,김영재,김정욱,장기택 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.1

이번 실험에서는 중합수축 응력이 가장 크게 나타나는 유구치 I급 와동에서 와동벽의 위치와 중합광원의 변화에 의해 다르게 나타나는 응력의 차이를 microtensile bond strength (MTBS)를 이용하여 알아보는 것을 목적으로 하였다. 교합면 법랑질을 제거한 하악 제 2유구치 30개를 준비하여 I급 와동을 형성하였다. 제조사의 지시에 따라 상아질 접착제를 도포 후 3가지 중합광원: 할로겐 램프, 플라즈마, 발광다이오드를 이용하여 10개씩 광중합하였다. 복합레진을 한꺼번에 충전 후 각각의 중합기로 광중합하였다. 동일 치아에서 각각 치수벽과 축벽의 MTBS 측정용 시편을 제작하고 각 군을 중합광원과 와동벽 위치에 따라 할로겐 램프-축군, 할로겐 램프-치수벽군, 플라즈마-축벽군, 플라즈마-치수벽군, 발광다이오드-축벽군, 발광다이오드-치수벽군의 6개 군으로 분류하였다. 만능시험기에서 MTBS를 측정하고 파절편과 와동의 단면을 SEM을 이용하여 관찰하였다. 동일 중합광원에서 와동벽 간 비교는 T-test, 동일 와동벽에서 중합광원 간 비교는 One-way ANOVA와 Tukey's post hoc test를 이용하였고 Weibull 분포분석을 하였다. 동일 중합광원 군간 비교에서 모두 치수벽 시편의 접착강도가 축벽 시편에 비해 유의하게 높았으며 동일 와동벽 군간 비교에서 모두 중합광원에 따른 접착강도가 유의한 차이를 보이지 않았다. 축벽 시편이 치수벽 시편보다 낮은 Weibull 변수(m)를 나타내었고 SEM 관찰 결과 축벽 시편에서 보다 더 불균일한 접착이 이루어진 것을 알 수 있었다. The purpose of present study was to determine whether different kinds of curing lights can alter microtensile bond strength(MTBS) of class I cavity pulpal and axial wall specimens in primary molar. Thirty clean mandibular 2nd primary molar's occlusal enamel were removed and class I cavity, size of 2×4×2 mm was prepared. Dentin bonding agent was applied according to manufacturer' s manual. Each group was cured with Halogen Curing Unit, Plasma Curing Unit and LED Curing Unit. Composite resin was bulk filled and photo cured with same curing unit. MTBS specimens which size is 0.7×0.7×4 mm were prepared with low speed saw. Specimens were coded by their curing lights and wall positions (Halogen - Axial wall group, Halogen - Pulpal wall group, Plasma - Axial wall group, Plasma - Pulpal wall group, LED - Axial wall group, LED - Pulpal wall group). MTBS were tested at 1 mm/min cross Head speed by Universal Testing Machine. Fractured surface and bonding surface was observed with SEM. T-test between axial and pulpal specimens in each curing lights, one-way ANOVA among different curing light specimens in each wall positions were done. Weibull distribution analysis was done. The results were as follows: Mean MTBS of pulpal wall specimens were significantly greater than that of axial wall specimens at each curing units(p<.05). There was no significant difference in the MTBS among three curing units at axial wall and pulpal wall. In Weibull distribution, pulpal wall specimens were more homogeneous than axial wall specimens.

Comparison of light transmittance in different thicknesses of zirconia under various light curing units

Isil Cekic-Nagas,Ferhan Egilmez,Gulfem Ergun 대한치과보철학회 2012 The Journal of Advanced Prosthodontics Vol.4 No.2

PURPOSE The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (α=.05). RESULTS ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance (P<.001). CONCLUSION Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.

가시광선과 플라스마 광선에 의한 복합레진 중합시 미세누출과 미세경도에 관한 연구

김상배,이광수 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.2

최근에 소개된 plasma arc curing units는 비교적 높은 광 강도를 가지고 짧은 시간내에 복합레진을 적절히 중합시킨다고 한다. 이 연구는 plasma arc curing units의 강한 광도와 짧은 시간에 의한 중합이 복합레진에 미치는 영향을 평가하기 위해 기존의 가시광선 중합기를 대조군으로 하여 표면 미세경도와 5급 수복물의 변연에 나타나는 미세누출을 색소침투방법으로 측정, 분석하여 다음과 같은 결론을 얻었다. 1. 각 깊이에서의 미세경도는 AHL군이 AP3, AP6군보다 모든 깊이에서 높았고, ZHL군보다 ZP6군이 표면에서 더 높았으며(P<0.05), 1mm와 2mm에서는 차이가 없었다(P<0.05). 그 외 모든 깊이에서 ZHL군이 ZP3, ZP6군보다 높았다(P<0.05). 2. 각 중합방법내 깊이에 따른 미세경도는 AHL군의 표면-1mm와 ZHL군의 1mm-2mm를 제외하고는 모든 군에서 깊이에 따라 감소되었다(P<0.05). 3. 교합면측과 치경부측 미세누출은 모든 중합군에서 교합면측이 낮게 나타났지만 유의한 차이는 없었다(P<0.05). 4. 중합방법간 미세누출은 모든 군에서 차이가 없었다(P<0.05). 5. 각 중합방법에 따른 재료간의 미세누출은 차이가 없었다(P<0.05). Newly developed curing units(plasma arc curing units) operate at relatively high intensity and are claimed to result in optimum properties of composite resin in a short curing time. The purpose of this study was to evaluate the microhardness and microleakage at the resin-tooth interface of two types of composite resins polymerized with visible light and plasma arc curing units. The results from the present study can be summarized as follows 1. Microhardness in each depth was shown to be higher in group AHL than AP3 & AP6, Group ZHL was low-er than AP6 at surface(P<0.05) and had no statistically significant difference at 1mm and 2mm(P>0.05). In other depths, group ZHL was higher than ZP3 and ZP6(P<0.05). 2. The incremental reduction in microhardness with depth was shown to be in all group except in surface-1mm of group AHL and 1∼2mm of group ZHL(P<0.05). 3. Degree of microleakage in all groups were shown to be higher in gingival margin than occlusal margin but no statistically significant difference(P>0.05). 4. Differences between curing methods in microleakage were shown to be no statistically significant differ-ence(P>0.05). 5. Differences between composite resins in microleakage were shown to be no statistically significant differ-ence(P>0.05).

Effects of 3 different light-curing units on the physico-mechanical properties of bleach-shade resin composites

Farzad Azin,Kasraei Shahin,Haghi Sahebeh,Masoumbeigi Mahboubeh,Torabzadeh Hassan,Panahandeh Narges 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.1

Objectives This study investigated the microhardness, flexural strength, and color stability of bleach-shade resin composites cured with 3 different light-curing units. Materials and Methods In this in vitro experimental study, 270 samples were fabricated of bleach and A2 shades of 3 commercial resin composites (Point 4, G-aenial Anterior, and Estelite Sigma Quick). Samples (n = 5 for each trial) were cured with Bluephase N, Woodpecker LED.D, and Optilux 501 units and underwent Vickers microhardness and flexural strength tests. The samples were tested after 24 hours of storage in distilled water. Color was assessed using a spectrophotometer immediately after preparation and 24 hours after curing. Data were analyzed using 3-way analysis of variance and the Tukey test (p ≤ 0.001). Results Samples cured with Optilux exhibited the highest and those cured with LED.D exhibited the lowest microhardness (p = 0.023). The bleach shade of Point 4 composite cured with Optilux displayed the highest flexural strength, while the same composite and shade cured with Sigma Quick exhibited the lowest (p ≤ 0.001). The color change after 24 hours was greatest for the bleach shade of G-aenial cured with Bluephase N and least for the A2 shade of Sigma Quick cured with Optilux (p ≤ 0.001). Conclusions Light curing with polywave light-emitting diode (LED) yielded results between or statistically similar to those of quartz-tungsten-halogen and monowave LED in the microhardness and flexural strength of both A2 and bleach shades of resin composites. However, the brands of light-curing devices showed significant differences in color stability. Objectives This study investigated the microhardness, flexural strength, and color stability of bleach-shade resin composites cured with 3 different light-curing units. Materials and Methods In this in vitro experimental study, 270 samples were fabricated of bleach and A2 shades of 3 commercial resin composites (Point 4, G-aenial Anterior, and Estelite Sigma Quick). Samples (n = 5 for each trial) were cured with Bluephase N, Woodpecker LED.D, and Optilux 501 units and underwent Vickers microhardness and flexural strength tests. The samples were tested after 24 hours of storage in distilled water. Color was assessed using a spectrophotometer immediately after preparation and 24 hours after curing. Data were analyzed using 3-way analysis of variance and the Tukey test (p ≤ 0.001). Results Samples cured with Optilux exhibited the highest and those cured with LED.D exhibited the lowest microhardness (p = 0.023). The bleach shade of Point 4 composite cured with Optilux displayed the highest flexural strength, while the same composite and shade cured with Sigma Quick exhibited the lowest (p ≤ 0.001). The color change after 24 hours was greatest for the bleach shade of G-aenial cured with Bluephase N and least for the A2 shade of Sigma Quick cured with Optilux (p ≤ 0.001). Conclusions Light curing with polywave light-emitting diode (LED) yielded results between or statistically similar to those of quartz-tungsten-halogen and monowave LED in the microhardness and flexural strength of both A2 and bleach shades of resin composites. However, the brands of light-curing devices showed significant differences in color stability.

Change of Vickers Hardness by Cavity Depth by Kind of Visible Light-curing Units and Composite Resins

김주원,정인호 대한예방치과학회 2010 International Journal of Clinical Preventive Denti Vol.6 No.2

Objective: With result that observe several studies of ancient sages, we can know that element that get in contraction and hardness of composite resin is various. Therefore, in this study, select each one in QTH LCU, PAC LCU, LED LCU and select 3 in dental composite resin. and observing Vickers hardness by cavity depth, I wished to help that select visible light-curing unit and composite resin. Materials and Method: Dental light curing units (LCU) that use in photo-polymerization are EXCELLED 2 (JOVIDENT, Germany), MONITEX LD-105 (FOMED DENTAL INC, Taiwan) and EXCELLED 2 (JOVIDENT, Germany) three kinds and dental composite resins that use in cavity restorations are Filtek Flowⓡ (3M-ESPE Co., USA), Filtek Supremeⓡ (3M-ESPE Co., USA) and CharmFilⓡ Plus (Dentkist, Korea) three kinds. Measurement machine that use in harness measurement is MVK-H1 (Akashi, Japan). Results and Conclusion: 1. When used composite resin-Filtek Supremeⓡ and polymerized by visible light-curing units-Apollo 95 E, vickers hardness high appear on the whole. 2. When used visible light-curing units-EXCELLED2, vickers hardness by cavity depth was significance in all composite resin, but when it is composite resin, hardness change by cavity depth was less best. 3. When used Apollo 95 E, Vickers hardness by cavity depth did not appear significance in all composite resin. When used visible light-curing units-MONITEX LD-105, only Filtek Flowⓡ-composite resin significance in Vickers hardness by cavity depth, but Filtek Supremeⓡ and CharmFilⓡ plus-composite resin significance did not appear. 4. When uses all visible light-curing units and packed by composite resin of 3 kinds, significance appeared in Vickers hardness in surface (0 mm), middle (3 mm), base (6 mm) of cavity.

Comparison of the bonding strengths of secondand third-generation light-emitting diode lightcuring units

Hee-Min Lee,Sang-Cheol Kim,Kyung-Hwa Kang,Na-Young Chang 대한치과교정학회 2016 대한치과교정학회지 Vol.46 No.6

Objective: With the introduction of third-generation light-emitting diodes (LEDs) in dental practice, it is necessary to compare their bracket-bonding effects, safety, and efficacy with those of the second-generation units. Methods: In this study, 80 extracted human premolars were randomly divided into eight groups of 10 samples each. Metal or polycrystalline ceramic brackets were bonded on the teeth using second- or third-generation LED light-curing units (LCUs), according to the manufacturers’ instructions. The shear bond strengths were measured using the universal testing machine, and the adhesive remnant index (ARI) was scored by assessing the residual resin on the surfaces of debonded teeth using a scanning electron microscope. In addition, curing times were also measured. Results: The shear bond strengths in all experimental groups were higher than the acceptable clinical shear bond strengths, regardless of the curing unit used. In both LED LCU groups, all ceramic bracket groups showed significantly higher shear bond strengths than did the metal bracket groups except the plasma emulation group which showed no significant difference. When comparing units within the same bracket type, no differences in shear bond strength were observed between the second- and third-generation unit groups. Additionally, no significant differences were observed among the groups for the ARI. Conclusions: The bracket-bonding effects and ARIs of secondand third-generation LED LCUs showed few differences, and most were without statistical significance; however, the curing time was shorter for the secondgeneration unit.

발광 다이오드 광중합기의 복합레진 중합 평가

강지은,전새로미,김종빈,김종수,유승훈 大韓小兒齒科學會 2014 大韓小兒齒科學會誌 Vol.41 No.2

최근 도입된 광범위 스펙트럼의 발광 다이오드 광중합기는 4개의 램프로 구성되어 있으며 다양한 중합 모드를 가지고 있다. 이 연구는 광범위 스펙트럼 발광 다이오드(VALO®, Ultradent, USA) 광중합기와 기존의 발광 다이오드 광중합기(EliparTM Freelight 2, 3M ESPE, USA)의 효율을 미세경도 시험을 통해 비교하였다. 연구에 사용한 광중합기는 VALO®와 EliparTM Freelight 2이며 중합 시간은 제조사의 지시에 따랐다. 37℃의 생리식염수에 중합된 레진 시편을 24시간 동안 보관한 후 미세경도 시험을 시행하였다. 시편 상부와 하부의 복합레진 미세경도는 공분산분석을 시행하였다. 광범위 스펙트럼의 발광 다이오드 광중합기를 이용하여 고성능 모드에서 4초, 플라즈마 모드에서 20초 광중합을 실시한복합레진 시편의 상부는 기존의 발광 다이오드 광중합기에 비해 미세경도가 증가하였으나(p < 0.05), 시편의 하부에서는 실험에 사용된 광중합기 간에 유의성 있는 차이를 보이지 않았다. The purpose of this study is to compare efficiency of broad spectrum LEDs (VALO®, Ultradent, USA) withconventional LED curing lights (EliparTM Freelight 2, 3M ESPE, USA) using a microhardness test. The light curing units used were VALO® in three different modes and EliparTM Freelight 2. The exposure timewas used according to the manufacturer's instructions. After cured resin specimens were stored in physiologicalsaline at 37℃ for 24 hours, microhardness was measured using Vickers microhardness tester. The microhardnessof upper and lower sides of the specimens were analyzed separately by the ANOVA method (Analysis ofVariance) with a significance level set at 5%. At upper side of resin specimens, an increased microhardness was observed in the broad spectrum LED curinglight unit with a high power mode for 4 seconds and plasma emulation mode for 20 seconds (p < 0.05). However, at the lower side of resin specimens, there were no significant differences in microhardness betweenbroad spectrum LED curing light unit and conventional LED curing light unit.