Impact of immediate and delayed light activation on self-polymerization of dual-cured dental resin luting agents

Acta Biomater. 2009 Jul;5(6):2095-100. doi: 10.1016/j.actbio.2009.01.030. Epub 2009 Feb 3.

Abstract

This study investigated the impact of immediate and delayed light activation on self-polymerization of a model dual-cured luting agent. The material presented the following components: base paste - 2,2-bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl]propane/triethylene glycol dimethacrylate (TEGDMA), camphorquinone, dimethyl-p-toluidine, butylated hydroxytoluene (BHT), glass fillers; catalyst paste - bisphenol-A ethoxylated dimethacrylate/TEGDMA, benzoyl peroxide, BHT, fillers. The pastes were mixed and seven polymerization scenarios tested: immediate light activation using low (5Jcm(-2)) or high (20Jcm(-2)) energy dose; delayed light activation (after 2min - short delay) using low or high dose; delayed light activation (after 10min - long delay) using low or high dose; and self-polymerization only. The degree of conversion (DC) and rate of polymerization (R(p)) were evaluated for 30min by real-time infrared spectroscopy. The lowest DC was detected for the self-polymerized and immediate-low dose groups, whereas the immediate-high dose and short delay-high dose groups showed the highest values. For the self-polymerized and immediate-high dose samples, R(p)(max) was detected after approximately 7s, whereas this took approximately 14s for the immediate-low dose group. R(p)(max) for the immediate-high dose group was higher than for the self-polymerized sample, which in turn was higher than for the immediate-low dose group. R(p)(max) for the short delay groups was higher than for the long delay groups. In conclusion, the extent of self-polymerization was influenced by the light dose reaching the material, which was dependent on high radiant exposure for optimal polymerization and the moment at which the light was applied; the short delay increased the DC for lower doses, while also generally decreasing the R(p) for all scenarios.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Composite Resins / chemistry*
  • Composite Resins / radiation effects*
  • Dental Cements / chemistry*
  • Dental Cements / radiation effects*
  • Dose-Response Relationship, Radiation
  • Elastic Modulus / radiation effects
  • Hardness / radiation effects
  • Hardness Tests
  • Light
  • Light-Curing of Dental Adhesives / methods*
  • Materials Testing
  • Photochemistry / methods
  • Radiation Dosage
  • Stress, Mechanical
  • Surface Properties / radiation effects

Substances

  • Composite Resins
  • Dental Cements