81 Isothermal Monomer Conversion of Model Quaternary-Ammonium-Methacrylate (-Acrylate) Resins

Thursday, March 22, 2012: 8 a.m. - 9:30 a.m.
Presentation Type: Oral Session
F. RUEGGEBERG, Oral Rehabilitation, Georgia Health Sciences University, Augusta, GA, A. TEZVERGIL-MUTLUAY, University of Turku, Turku, Finland, S. LOONEY, Biostatistics, Georgia Health Sciences University, Augusta, GA, M. CADENARO, Department of Medical Sciences, University of Trieste, Trieste, Italy, L. BRESCHI, Department of Biomedicine, University of Trieste, Trieste, Italy, and D. PASHLEY, Dept. Oral Biology, Georgia Health Sciences University, Augusta, GA

Objectives: To determine monomer conversion of a range of quaternary ammonium-methacrylates (-acrylates) (QAMs) at 25░C. Methods: A range of commercial QAMs were added to co-monomer mixtures of TEGDMA (30 wt%), HEMA (10 wt%), and BisGMA (wt% varied) in water and rendered photocurable by addition of 1% wt TPO: ATA (acrylate) (5, 10, 15 wt%); MCMS (5, 10, 15 wt%), METMAC (5, 10, 15 wt%); MAPTAC 5 wt%, DDAC 5 wt%; a custom non-QAM control (NQC); and a commercial control (Scotchbond Multipurpose Adhesive bottle (SBMP) (3M ESPE). Abbreviations defined in J Dent Res 2011;90:525-540. Thin films of uncured fluid (≈160 microns) were placed on the diamond element of a horizontal attenuated total reflectance unit in a Fourier transform infrared spectrometer and heated to 25░C for 2 min prior to application of 60s light curing (Optillux 401, Kerr). Real-time spectra were obtained at 2cm-1 resolution (1/s) and total conversion 600s following light application was determined using changes in absorption at 1318 cm-1 (vinyl in-plane trans (=CH) rock. Five replications per test condition were made. Data were subjected to a 1-way ANOVA. All comparisons were made at a pre-set alpha of 0.05. áResults: ANOVA indicated failure of Shapiro-Wilk normality test, so Kruskal-Wallis 1-Way ANOVA on ranks was performed, with the Tukey post-host test. Table presents ranking of resin systems based on median conversion.

QAM-containing resin median conversions ranged from a low of 78.8% for METMAC 5% to a high of 91.0% for MCMS 15%. Increasing QAM content within a given resin type resulted in increased cure ranking. Median conversion of ATA 10%, DDAC 5%, ATA 15%, and MCMS 15% ranked higher than non-QAM commercial product (SBMP).

Conclusions: Isothermal monomer conversion of some model QAM-containing resins demonstrated significantly greater conversion than a commercial resin adhesive formulation. Increased QAM content resulted in higher median conversion.


This abstract is based on research that was funded entirely or partially by an outside source: NIH/NIDCR Grant RO1DE015306 and Academy of Finland Grant #8126472

Keywords: Acrylics, Dental materials, Polymerization, Polymers and Quaternary ammonium-methacrylate
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