Increased rates of photopolymerisation by ternary type II photoinitiator systems in dental resins

Adriano Fonseca Lima, Marcos Vinicius Oliveira Salvador, Diogo Dressano, Cintia Helena Coury Saraceni, Luciano Souza Gonçalves, Mohammed Hadis, William M Palin

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10 Citations (Scopus)
373 Downloads (Pure)

Abstract

To evaluate the effects of Type I and Type II photoinitiator systems on curing efficiency, degree of conversion (DC) and chemico-physical properties of resin based materials. A comonomer base containing 50%wt 2.2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA) and 50%wt triethyleneglycol dimethacrylate (TEGDMA) was formulated with either 0.5 or 1mol% of Type II camphoroquinone (CQ), Type I monoacylphosphine oxide (MAPO) or bis-acylphosphine oxide (BAPO) photoinitiators. The Type II system was either a binary (1: 2 CQ:amine) or ternary system (1: 2 CQ:amine + 0.5 mol% DPI). Degree and rate of polymerization was measured by Fourier Transform Infrared Spectroscopy (FTIR). Knoop micro-hardness prior to and following ethanol immersion was assessed. Flexural strength and modulus was measured under three-point bend test. Water sorption and solubility was also evaluated. The photoinitiator absorption spectra and the total absorbed energy per unit volume (Eabs) for 0.5mol% photoinitiator in each material was calculated. Despite the reduced total absorbed energy per unit volume for CQ based systems, ternary Type II system significantly improved curing efficiency (P < 0.05) compared to both Type I photoinitiators and degree of conversion compared to MAPO only, whilst exhibiting comparable mechanical and physical properties compared to both Type I based materials at equivalent molar concentrations of photoinitiator (P > 0.05). Ternary Type II systems is an efficient alternative to improve the polymerization of resin materials, promoting similar or even better properties than Type I initiators. DPI can increase the reactivity of CQ systems and promote polymerization rates superior than Type I photoinitiators.

Original languageEnglish
Pages (from-to)71-78
Number of pages8
JournalJournal of the Mechanical Behavior of Biomedical Materials
Volume98
Early online date6 Jun 2019
DOIs
Publication statusPublished - Oct 2019

Bibliographical note

Copyright © 2019. Published by Elsevier Ltd.

Keywords

  • Mechanical properties
  • Dental resins
  • Initiators
  • Dental materials

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