Effectiveness of Hi-shine polishing compound on autopolymerization acrylic denture resin

Objectives: To evaluate the effectiveness of a hi-shine polishing compound (HSP) on the surface roughness of polymethylmethacrylate autopolymerization denture base acrylic resin (PAR) material.
Methods: 120 specimens, 43x38x5 mm, were prepared using PAR (Lucitone 199; Dentsply, York, USA). Immediately prepared, the specimens were roughened using 500-grit sandpaper under tap water. They were divided into four groups based on polishing mediums: medium grit Pumice (Kerr, Romulus, USA), Polycril (EH mdc dental, Jalisco, Mexico), Dazzle PS (Whip Mix, Louisville, USA), and Diatomaceous Earth (Safer, litilz, USA). Pumice was served as a reference. Specimens were polished four times of 15 seconds with a conventional lathe (Red Wing, Handler, Westfield, USA) polishing using slurry material. There were 5 seconds rests between each polishing for reapplying material. Each group was subdivided into two groups of 15; Hi-shine compound, Acrlylustre (Buffalo, Syosset, USA), was used 15 specimens of each group for 15 seconds. All are polished with light pressure at high speed and by one investigator. Three measurements of surface roughness of the PAR specimens were performed using a Surface Roughness Tester (Mitutoyo, Japan) by the instrument’s stylus as it moved across the surface under constant pressure. Mean average surface roughness (Ra) values of each specimen were analyzed using the Kruskal-Wallis.
Results: All the specimens showed the decreased roughness after used HSP. Diatomaceous Earth produced smoother surface than others. The surface roughness differences present between all four groups (p<0.05) after HSP polishing compared to using different polishing mediums; however, there were no significant differences between each groups (p>0.05) after polished using the same HSP.
Conclusions: Conventional lathe polishing produced the smooth surface of denture base acrylic. Using hi-shine polishing compound produced significantly smoother surfaces whether or not used different initial polishing medium.