1374 Effect of Curing Light on the Polymerization of Resin Cement

Saturday, March 24, 2012: 9:45 a.m. - 11 a.m.
Presentation Type: Poster Session
M.Q. ALQAHTANI1, M.M. ALSHAAFI1, R.B. PRICE2, and C.M. FELIX2, 1Restorative Dental Sciences, King Saud University, Riyadh, Saudi Arabia, 2Dental Clinical Sciences, Dalhousie University, Halifax, NS, Canada
Objective: Adequate polymerization of resin cement under ceramic restorations is an important factor to obtain adequate physical and biological properties. This study examined the effect of selecting single-peak vs. polywave emission LED curing light on the Degree of Conversion-(DC) and Knoop-microhardness-(KHN) of resin cement when they were light cured through a ceramic disc.

Method:  Two shades-(A1&A4) of resin cement (Variolink-II, Ivoclar-Vivadent) were used in a 0.5mm thick ring. The top surfaces were covered with a Mylar strip and further covered with a disc of 1mm thick shade A2 Empress Esthetic ceramic. The specimens were light cured using an Elipar-S10-(3m-ESPE, single-peak LED) delivering 13.6-J/cm2, or the BluePhase-G2-(Ivoclar-Vivadent,polywave-LED) delivering 9.8-J/cm2 of energy.

Both lights were used for 20s to cure the resin specimens directly on the surface of a Golden Gate Attenuated Total Reflectance FT-IR plate that was heated to 30°C. The DC of the resin was calculated after 100-seconds. The specimens were removed and the KHN was immediately tested, and again after 24-hours storage in the dark at 37°C and 100% humidity. Five specimens were made and tested in each group. The DC and KHN results were analyzed with ANOVA and Fischer’s PLSD at α = 0.05.

Result: The choice of curing light had no significant effect on the DC and only a small effect on the immediate and 24-hrs KHN values. Shade A4 harder and better DC than A1.


Light Type



24-HRS –KHN-Mean(SD)



0.594( 0.008)(a)




0.605( 0.008)(a)












Letters in parentheses = Homogeneous subsets-(Fischer’s α=0.05)

 Conclusion:  The small differences in the DC and KHN values achieved using the Single-Peak and Polywave curing lights are probably not clinically significant and either light could be used. Shade A4 was slightly harder than A1.

This abstract is based on research that was funded entirely or partially by an outside source: This Study was supported by Research Group Fund # RGP- VPP-146 , Deanship of Scientific Research, King Saud University and Dalhousie University

Keywords: Cements, Ceramics, Dental materials, Hardness and Polymerization