Light-activation through indirect ceramic restorations: does the overexposure compensate for the attenuation in light intensity during resin cement polymerization?

Abstract

OBJECTIVES:

This study evaluated the effects of light exposure through simulated indirect ceramic restorations (SICR) on hardness (KHN) of dual-cured resin cements (RCs), immediately after light-activation and 24 h later.

MATERIAL AND METHODS:

Three dual-cured RCs were evaluated: Eco-Link (Ivoclar Vivadent), Rely X ARC (3M ESPE), and Panavia F (Kuraray Medical Inc.). The RCs were manipulated in accordance to the manufacturers' instructions and were placed into cylindrical acrylic matrixes (1-mm-thick and 4-mm diameter). The RC light-activation (Optilux 501; Demetron Kerr) was performed through a glass slide for 120 s (control group), or through 2-mm or 4-mm thick SICRs (IPS Empress II; Ivoclar Vivadent). The specimens were submitted to KHN analysis immediately and 24 h after light-activation. The data obtained at the 2 evaluation intervals were submitted to 2-way ANOVA repeated measures and post-hoc Tukey's test (pre-set alpha of 5%).

RESULTS:

Lower KHN was observed when light-activation was performed through SICRs for Eco-Link at all evaluation intervals and for Rely X ARC 24 h later. For Panavia F, no significant difference in KHN was observed between control and experimental groups, regardless of evaluation interval. Most groups exhibited higher KHN after 24 h than immediately after light-activation, with the exception of Rely X ARC light-activated through SICR, as no significant difference in KHN was found between evaluation intervals.

CONCLUSIONS:

Light overexposure did not compensate for light intensity attenuation due to the presence of SICR when Rely X and Eco-Link were used. Although hardness of such RCs increased over a 24-h interval, the RCs subjected to light overexposure did not reach the hardness values exhibited after direct light exposure.

• Authors: Albano Luis Novaes Bueno, Cesar Augusto Galvão Arrais, Ana Carolina Tedesco Jorge, Andre Figueiredo Reis, Cristiane Mariote Amaral
• Journal: Journal of applied oral science : revista FOB (J Appl Oral Sci) 2011 Jan-Feb Vol. 19 Issue 1 Pg. 22-7 ISSN: 1678-7765 [Electronic] Brazil
• PMID: 21437465 (Publication Type: Journal Article)

Chemical References

• Panavia-Fluoro
• Polymethacrylic Acids
• RelyX ARC
• Resin Cements
• Polyethylene Glycols
• Bisphenol A-Glycidyl Methacrylate

Topics

• Analysis of Variance
• Bisphenol A-Glycidyl Methacrylate (chemistry, radiation effects)
• Ceramics (chemistry, radiation effects)
• Hardness Tests
• Light-Curing of Dental Adhesives (methods)
• Materials Testing
• Polyethylene Glycols (chemistry, radiation effects)
• Polymerization (radiation effects)
• Polymethacrylic Acids (chemistry, radiation effects)
• Resin Cements (chemistry, radiation effects)
• Self-Curing of Dental Resins (methods)
• Surface Properties (radiation effects)
• Time Factors