Abstract: Effect of glazing with an ultraviolet light-activated coating material on reduction of the leaching of methyl methacrylate and formaldehyde from denture acrylic resins was quantitatively evaluated. Disks prepared from auto-polymerized resins were painted with the material and radiated with ultraviolet light. The disks were immersed in artificial saliva and the concentrations of methyl methacrylate and formaldehyde leached were determined by high performance liquid chromatography and flow injection analysis. Compared to untreated controls, the glaze significantly decreased concentrations of both leachable substances. Treatment with an ultraviolet light-activated coating material is effective in suppressing the leaching of methyl methacrylate and formaldehyde from acrylic resins as well as in smoothing the denture surfaces.

Abstract: A closed-loop flow system was developed and used to study semicontinuous emulsion polymn. reactions by ESR . Latex was continuously circulated during a polymn. from a custom reactor through the ESR cavity equipped with a customized flat cell and then back to the reactor. The utility of this system was illustrated by following the propagating free radical concentration. in a semicontinuous emulsion polymn. of Me methacrylate at 50°C. The experimental results showed that the average number of free radicals per particle increased during the reaction due to a steady accumulation of free radicals as the particle size increased, which indicated the presence of 'trapped' radicals. The relatively small increase in radical concentrations. based on polymer volume suggested that a radical required a min. polymer volume to remain unterminated.