Influence of energy density of different light sources on knoop hardness of a dual-cured resin cement

Authors

  • Evandro Piva Federal University of Pelotas; Dental School; Department of Restorative Dentistry
  • Lourenço Correr-Sobrinho State University of Campinas; Dental School of Piracicaba; Dental Materials Area; Department of Rest orative Dentistry
  • Mario Alexandre Coelho Sinhoreti State University of Campinas; Dental School of Piracicaba; Dental Materials Area; Department of Rest orative Dentistry
  • Simonides Consani State University of Campinas; Dental School of Piracicaba; Dental Materials Area; Department of Rest orative Dentistry
  • Flávio Fernando Demarco State University of Campinas; Dental School of Piracicaba; Dental Materials Area; Department of Rest orative Dentistry
  • John Michael Powers University of Texas Dental Branch at Houston; Restorative Dentistry and Biomaterials

DOI:

https://doi.org/10.1590/S1678-77572008000300005

Keywords:

Hardness test, Resin cements, Ceramics, Dental materials

Abstract

The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs) were tested: tungsten halogen light (HAL), light-emitting diode (LED) and xenon plasma-arc (PAC) lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce). Three energy doses were used by modifying the irradiance (I) of each LCU and the irradiation time (T): 24 Jcm-2 (I/2x2T), 24 Jcm-2 (IxT) and 48 Jcm-2 (Ix2T). Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus). Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10). Knoop hardness number (KHN) means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (a=5%). Application of 48 J.cm-2 energy dose through the ceramic using LED (50.5±2.8) and HAL (50.9±3.7) produced significantly higher KHN means (p<0.05) than the control (44.7±3.8). LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.

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Published

2008-06-01

Issue

Section

Original Articles

How to Cite

Piva, E., Correr-Sobrinho, L., Sinhoreti, M. A. C., Consani, S., Demarco, F. F., & Powers, J. M. (2008). Influence of energy density of different light sources on knoop hardness of a dual-cured resin cement . Journal of Applied Oral Science, 16(3), 189-193. https://doi.org/10.1590/S1678-77572008000300005