Faculty Articles
Title
The Effect of Ceramic Restoration Shade and Thickness on the Polymerization of Light and Dual-cure Resin Cements
ISBN or ISSN
0361-7734
Publication Title
Operative Dentistry
Volume
36
Issue
6
Date of original Performance / Presentation
November 2011
Publication Date / Copyright Date
11-1-2011
First Page
661
Last Page
669
DOI Number
10.2341/10-206-L
Abstract
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 (p<0.0001). Ceramic shade had a significant effect only on Calibra in both LC and DC groups (p<0.0001). Microhardness values of LC groups were significantly lower than DC groups (p<0.0001). Control groups had significantly higher hardness values in all cement groups (p<0.0001). There was a significant correlation between the amount of light transmitted and hardness (p=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.
Disciplines
Medical Specialties | Medicine and Health Sciences | Osteopathic Medicine and Osteopathy
NSUWorks Citation
Kilinc, E.; Antonson, S. A.; Hardigan, Patrick C.; and Kesercioglu, A., "The Effect of Ceramic Restoration Shade and Thickness on the Polymerization of Light and Dual-cure Resin Cements" (2011). Faculty Articles. 372.
https://nsuworks.nova.edu/hpd_com_faculty_articles/372
