Saleha Nisar, Faisal Moeen, Yawar Hayat Khan.
Effect of curing regimes on physical properties of heat cure acrylic resin.
Pak Oral Dental J Jan ;36(1):156-60.

This study was conducted to determine the effect of varying curing conditions on the residual monomer concentrations of heat cure acrylic denture resin. Sixty-four disc shaped acrylic resin specimens were processed at four powder-liquid ratios (2.22, 2.00, 1.80 and student-ratio) and cured in a heated water bath using 4 different curing regimes (two with a terminal boil and two without). The residual monomer concentrations were determined at intervals of 24, 48 and 72 hours using a UV Spectrophotometer. The results indicated a decrease in residual monomer concentration with storage time. Group 4 (student-ratio) and curing by cycle 2B (placing the assembly in the water bath directly at 100°C) showed the highest overall residual monomer concentrations while group 1 (highest powder-liquid ratio) and curing by cycle 1A showed the least overall residual monomer concentrations It was concluded that students dispensing acrylic powder and liquid monomer without calculations would lead to higher residual monomers if a proper curing regime is not followed. Using a 60 minute terminal boil in the polymerization process is strongly recommended. Storing the acrylic denture bases for at least 24-48 hours in water before use will decrease residual monomers being leached into the oral environment.

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