Oxygen inhibition in dental resins.
Oxygen inhibits free radical polymerization and yields polymers with uncured surfaces. This is a concern when thin layers of resin are being polymerized, or in circumstances where conventional means of eliminating inhibition are inappropriate. In this study, we tested the hypothesis that viscosity, filler content, and polymerization temperature modify oxygen diffusion in the resin or the reactivity of radical species, and affect the degree of conversion near the surface. Confocal Raman micro-spectroscopy was used to measure monomer conversion from the surface to the bulk of cured resins. Increased viscosity was shown to limit oxygen diffusion and increase conversion near the surface, without necessarily modifying the depth of inhibition. The filler material was shown to increase, simultaneously, oxygen diffusivity and the viscosity of the resin, which have opposite effects on conversion. Polymerization at a temperature above approximately 110 degrees C was shown to eliminate oxygen inhibition.
Gauthier
M A
MA
Department of Chemistry, Université de Montréal, POB 6128, Downtown Station, Montreal, Quebec H3C3J7, Canada.
Stangel
I
I
Ellis
T H
TH
Zhu
X X
XX
D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects*; D003799:Dental Stress Analysis; D004058:Diffusion; D005609:Free Radicals / Q000737:chemistry; D008027:Light; D008422:Materials Testing; D008872:Microwaves; D010100:Oxygen / Q000737:chemistry*; D010316:Particle Size; D013059:Spectrum Analysis, Raman; D044366:Transition Temperature; D014783:Viscosity
D003188:Composite Resins; D005609:Free Radicals; D010100:Oxygen