Chemical polishing of acrylics- dipping time and its effect on surface roughness

Objective: To find out the optimum time to be used for chemical polishing of acrylic resins.Methodology: Twenty four specimens of heat activated acrylic resin and twenty four of chemically activated acrylic resin measuring 75 x 23 x 4 mm were fabricated. In each specimen four markings were made. The surface roughness was measured with contact profilometer. Each specimen was treated with monomer kept at 75degrees for time intervals varying from 15 to 60 seconds. The surface roughness (Ra)was evaluated after the treatment as chemical polishing using heated monomerResults: The mean surface roughness before polishing in heat cure specimens was 0.3348μm and that of self cure specimens was 0.3348 μm. After polishing for 60 seconds it showed 0.3265 μm and 0.3288 μm.Conclusion: The surface roughness reduced by 0.83% in heat cure specimens and by 1.04% in cold cure specimens when they were treated for 60 seconds.60 seconds can be taken as the optimum time for chemical polishing.