In vitro 2D and 3D roughness and spectrophotometric and gloss analyses of ceramic materials after polishing with different prophylactic pastes

Statement of problem: The effect of prophylactic polishing pastes on composite resin materials has been extensively investigated, but little is known about their effect on ceramic materials. Purpose: The purpose of this in vitro study was to evaluate the effect of prophylactic polishing pastes on the 2D and 3D roughness, translucency, and gloss of different ceramic materials. Material and methods: A total of 120 flat specimens (thickness: 2 mm) obtained from computer-aided design and computer-aided manufacturing (CAD-CAM) blocks of leucite glass-ceramic (Empress CAD), lithium disilicate glass-ceramic (e.max CAD), and zirconia (Zenostar MT) were glazed and sintered. Forty specimens from each material were then divided into 4 groups and polished with Cleanic fine, Nupro fine, or Proxyt fine pastes, leaving the control group untreated. The specimens were polished for 2 minutes with a prophylaxis cup mounted on a handpiece, applying a constant load of 3.9 N at 2000 rpm. Surface roughness was measured by using a contact profilometer and a 3D optical profilometer. The translucency parameter and gloss value were calculated by using a spectrophotometer and a glossmeter. One specimen per group was observed by scanning electron microscopy at ×200 magnification. Differences in means were compared by using 2-way ANOVA followed by the Tukey honestly significant difference (HSD) test (α=.05). Results: The 2D roughness of Empress was lower than that of e.max (P<.05) and was increased by using Cleanic fine and Nupro fine pastes (P<.05). The translucency parameter values of Empress and Zenostar decreased with the use of Nupro fine paste (P<.05). Zenostar showed the lowest translucency (P<.05). The effect of prophylactic polishing pastes on gloss was minimal (P>.05). The gloss of Empress was higher than that of Zenostar and e.max (P<.05). The Pearson correlation showed that gloss and surface roughness were correlated (P<.001). Conclusions: Polishing procedures can alter the surface of a ceramic restoration.