Effect of Prophylactic Polishing Pastes on Roughness and Translucency of Lithium Disilicate Ceramic

This study evaluated the effect of prophylactic polishing pastes on the roughness and translucency of lithium disilicate ceramic. Sixty specimens were obtained from e.max CAD blocks. After ground finishing, each specimen was glazed and randomly divided into one of five groups, including one control group. They were then polished with one of four types of prophylactic paste. Group A: Nupro coarse, group B: Nupro medium, group C: Nupro fine, and group D: Cleanic. Specimens were polished with these pastes for 2 minutes with a prophy cup mounted on the handpiece under a constant load of 400 gr at 3,000 rpm. After polishing, the specimens were cleaned ultrasonically in distilled water and dried. The surface roughness (Ra, μm) was then measured using a surface profilometer. The translucency analysis was carried out on the glazed (control group) and polished specimens using a dental spectrophotometer. For each specimen, measurements were made once with a white and once with a black background. Group A showed significantly less surface roughness compared with the control group and groups B, C, and D. The control group showed significantly higher translucency compared with the other groups (P .05). Despite the good abrasion resistance of e.max CAD lithium disilicate ceramic, prophylactic pastes produced a reduction in translucency. Surface roughness varied depending on the paste used. Polishing procedures should be carried out with caution to not compromise the esthetics achieved with prosthetic restorations. (Int J Periodontics Restorative Dent 2014;34:e26-e29. doi: 10.11607/prd.1155)