The Effect of Ceramic Restoration Shade and Thickness on the Polymerization of Light- and Dual-cure Resin Cements
- 1 November 2011
- journal article
- research article
- Published by Operative Dentistry in Operative Dentistry
- Vol. 36 (6), 661-669
- https://doi.org/10.2341/10-206-l
Abstract
Resin cements are generally considered as the material of choice in cementation of all-ceramic restorations. The decision between light- and dual-cure resin cement may depend on the properties of the ceramic restoration as well as the location of the tooth. The ceramic thickness has a more intense effect on polymerization than ceramic shade. Objectives: Inadequately polymerized resin cements may negatively affect the clinical performance of cemented all-ceramic restorations. The purpose of this in vitro study was to evaluate the effect of ceramic thickness and shade on the microhardness of various light-cured (LC) and dual-cured (DC) resin cements. The amount of light transmission through the restoration was also evaluated to correlate the results. Methods: Three different brands of resin cements (Appeal/Ivoclar; Calibra/Dentsply; Nexus 2/Kerr) were used in LC and DC forms to prepare disk-shaped samples (0.5-mm thickness × 5-mm diameter) (n=15). Study group samples were light-cured for 40 seconds (Flashlite 1401/Discus Dental) through four shades (ETC1, ETC2, ETC3, ETC4) and four thicknesses (1 mm, 2 mm, 3 mm, 4 mm) of all-ceramic ingot discs (IPS Empress Esthetic/Ivoclar). Control samples were directly cured without the presence of ceramic. The light transmission through various shades and thicknesses of ceramics was measured using a hand-held radiometer (Demetron, Kerr). Vickers microhardness measurements were performed (Micromet/Buehler) at 24 hours following dark storage in 37°C water. Correlation between ceramic shade, thickness, and light intensity readings (mW/cm2) with respect to microhardness was statistically evaluated using analysis of variance (p=0.05). Results: Ceramic thickness of 3 mm and/or above significantly decreased the microhardness values in all LC and DC groups (ppppp=0.000). Conclusion: The ceramic thickness has a more intense effect on polymerization compared to the ceramic shade. Overlying ceramic thickness of 3 mm and above was found to adversely affect the polymerization of LC and DC resin cements and therefore a 3-mm thickness was considered the critical threshold.Keywords
This publication has 21 references indexed in Scilit:
- Effect of exponential polymerization on color stability of resin-based filling materialsDental Materials, 2007
- Properties of dual‐curable luting composites polymerized with single and dual curing modesJournal of Oral Rehabilitation, 2003
- Color stability and hardness in dental composites after accelerated agingDental Materials, 2003
- Relative translucency of six all-ceramic systems. Part II: Core and veneer materialsThe Journal of Prosthetic Dentistry, 2002
- Influence of visible-light exposure on colour stability of current dual-curable luting composites.Journal of Oral Rehabilitation, 2002
- The effect of post-cure heating on residual, unreacted monomer in a commercial resin compositeDental Materials, 2000
- Five-year color changes of light-cured resin composites: influence of light-curing timesDental Materials, 1999
- Dental luting agents: A review of the current literatureThe Journal of Prosthetic Dentistry, 1998
- The effect of porcelain color on the hardness of luting composite resin cementThe Journal of Prosthetic Dentistry, 1993
- Influence of ceramic thickness on the polymerization of light-cured resin cementThe Journal of Prosthetic Dentistry, 1990