Effect of Ethanol Addition on some Properties of Self-Polymerized Acrylic Resins

Background: Self-polymerized acrylic resins are widely utilized in dentistry. A higher residual monomer content is seen after polymerization of denture base resins.                    The literature showed that the ethanol solvent could rise the leaching of residual monomer from the polymer. The purpose of the current research was to investigate the influence of ethanol addition on hardness and roughness of acrylic resins. Materials and Methods: Sixty acrylic resin specimens were prepared and were divided into 2 main sets due to the kind of test used (surface hardness and surface roughness). There were three groups according to the ethanol concentrations. The first group was the control specimens with no ethanol, the second group was loaded with 10 ml of ethanol; and the third group was loaded with 15 ml of ethanol. The acrylic specimens were measured using the Shore A Durometer hardness and the surface roughness tester. Results: showed that the addition of ethanol significantly decrease the surface hardness of acrylic resins. The results indicated that there are significant     differences      between           groups  (P<       0.0010). However, no significant differences between 10ml and 15 ml groups (P>0.05). For surface roughness test, no significant differences were found among the studied groups (P>0.05). Conclusions: The addition of ethanol to self-polymerized acrylic resins would significantly decrease the hardness and increases the surface roughness of acrylic resins