Behaviour of curing conditions on the properties of Acrylic resin

Inspite the extensive use of Poly methyl methacrylate (PMMA) in dentistry, complications associated with their inherent property related limitations and processing havebeen documented. Acrylic resins is a thermoplastic substance derived from acrylic acid, methacrylic acid or other related compounds The chemical name of the resin which produced from the methyl methacrylate monomer (MMA) is polymethyl methacrylate. MMA is a transparent and colorless substance. It is also highly resistant to weather damage. In this study the effect of the different conditions on the residual monomer concentrations of heat cure acrylic resin has been evaluated. And the effect of curing temperature and time has been investigated. Several acrylic resin samples were prepared with four powder-liquid ratios (2.20, 2.00, 1.80 and student-ratio) carefully and cured with 4 different conditions in a heated water baths (two with a terminal boil and two without). The residual monomer concentrations were determined at 24, 48 and 72 hours duration. The release of residual monomer, decrease with at least 24-48 hours storage time in water before using. A decreasing in residual monomer concentration with storage time has been shown in our investigation. 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. On the other hand, curing conditions influence residual monomer concentration more than powder liquid ratio .

کلیدواژه ها:

Acrylic ، Curing ، resin ، heat ، monomer