Restorative Dentistry & Endodontics

Power density of light curing units through resin inlays fabricated with direct and indirect composites: Hoon-Sang Chang, Young-Jun Lim, Jeong-Mi Kim, Sung-Ok Hong; J Korean Acad Conserv Dent 2010;35(5):353-358. Published online September 30, 2010; DOI: https://doi.org/10.5395/JKACD.2010.35.5.353

Abstract PDF PubReader ePub: Objectives
The purpose of this study was to measure the power density of light curing units transmitted through resin inlays fabricated with direct composite (Filtek Z350, Filtek Supreme XT) and indirect composite (Sinfony).
Materials and Methods
A3 shade of Z350, A3B and A3E shades of Supreme XT, and A3, E3, and T1 shades of Sinfony were used to fabricate the resin inlays in 1.5 mm thickness. The power density of a halogen light curing unit (Optilux 360) and an LED light curing unit (Elipar S10) through the fabricated resin inlays was measured with a hand held dental radiometer (Cure Rite). To investigate the effect of each composite layer consisting the resin inlays on light transmission, resin specimens of each shade were fabricated in 0.5 mm thickness and power density was measured through the resin specimens.
Results
The power density through the resin inlays was lowest with the Z350 A3, followed by Supreme XT A3B and A3E. The power density was highest with Sinfony A3, E3, and T1 (p < 0.05). The power density through 0.5 mm thick resin specimens was lowest with dentin shades, Sinfony A3, Z350 A3, Supreme XT A3B, followed by enamel shades, Supreme XT A3E and Sinfony E3. The power density was highest with translucent shade, Sinfony T1 (p < 0.05).
Conclusions
Using indirect lab composites with dentin, enamel, and translucent shades rather than direct composites with one or two shades could be advantageous in transmitting curing lights through resin inlays.

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The polymerization rate and the degree of conversion of composite resins by different light sources: Joo-Hee Ryoo, In-Bog Lee, Hyun-Mee Yoo, Mi-Ja Kim, Chang-In Seok, Hyuk-Choon Kwon; J Korean Acad Conserv Dent 2004;29(4):386-398. Published online July 31, 2004; DOI: https://doi.org/10.5395/JKACD.2004.29.4.386

Abstract PDF PubReader ePub: Objectives
The purpose of this study was to observe the reaction kinetics and the degree of polymerization of composite resins when cured by different light sources and to evaluate the effectiveness of the blue Light Emitting Diode Light Curing Units (LED LCUs) compared with conventional halogen LCUs.
Materials and Methods
First, thermal analysis was performed by a differential scanning calorimeter (DSC). The LED LCU (Elipar Freelight, 320 mW/cm²) and the conventional halogen LCU (XL3000, 400 mW/cm²) were used in this study for curing three composite resins (SureFil, Z-250 and AEliteFLO). Second, the degree of conversion was obtained in the composite resins cured according to the above curing mode with a FTIR. Third, the measurements of depth of cure were carried out in accordance with ISO 4049 standards. Statistical analysis was performed by two-way ANOVA test at 95% levels of confidence and Duncan's procedure for multiple comparisons.
Results
The heat of cure was not statistically different among the LCUs (p > 0.05). The composites cured by the LED (Exp) LCUs were statistically more slowly polymerized than by the halogen LCU and the LED (Std) LCU (p < 0.05). The composite resin groups cured by the LED (Exp) LCUs had significantly greater degree of conversion value than by the halogen LCU and the LED (Std) LCU (p = 0.0002). The composite resin groups cured by the LED (Std) LCUs showed significantly greater depth of cure value than by the halogen LCU and the LED (Exp) LCU (p < 0.05).

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EFFECT OF LIGHT SOURCE AND SHADE ON DEPTH OF CURE OF COMPOSITES: Joon-Sok Na, Sun-Wa Jeong, Yun-Chan Hwang, Sun-Ho Kim, Chang Yun, Won-Mann Oh, In-Nam Hwang; J Korean Acad Conserv Dent 2002;27(6):561-568. Published online January 14, 2002; DOI: https://doi.org/10.5395/JKACD.2002.27.6.561

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ABSTRACT

Purpose of this research is estimating polymerization depth of different source of light. XL 3000 for halogen light, Apollo 95E for plasma arc light and Easy cure for LED light source were used in this study. Different shade (B1 & A3) resin composites (Esthet-X, Dentsply, U.S.A.) were used to measure depth of cure. 1, 2, and 3 mm thick samples were light cured for three seconds, six seconds or 10 seconds with Apollo 95E and they were light cured with XL-3000 and Easy cure for 10 seconds, 20 seconds, or 40 seconds. Vicker's hardness test carried out after store samples for 24 hours in distilled water.

Results were as following.

Curing time increases from all source of lights, curing depth increased(p<0.05).

Depth (that except 1mm group and 2mm group which lighten to halogen source of light) deepens in all groups, Vickers hardness decreased(p<0.05).

Vicker's hardness of A3 shade composite was lower in all depths more than B1 shade composites in group that do polymerization for 10 seconds and 20 seconds using halogen source of light(p<0.05), but group that do polymerization for 40 seconds did not show difference(p>0.05).

Groups that do polymerization using Plasma arc and LED source of light did not show Vicker's hardness difference according to color at surface and 1mm depth(p>0.05), but showed difference according to color at 2mm and 3mm depth(p<0.05). The results showed that Apollo 95E need more polymerization times than manufacturer's recommendation (3 seconds), and Easy cure need polymerization time of XL-3000 at least.

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