title: Influence of polishing procedures on the surface roughness of dental ceramics made by different techniques.
abstract: The aim of this study was to evaluate the influence of 2 different surface polishing procedures-glazing and manual polishing-on the roughness of ceramics processed by computer-aided design/computer-aided manufacturing (CAD/CAM) and conventional systems (stratification technique). Eighty ceramic discs (diameter: 8 mm, thickness: 1 mm) were prepared and divided among 8 groups (n = 10) according to the type of ceramic disc and polishing method: 4 GZ and 4 MP. Specimens were glazed according to each manufacturer's recommendations. Two silicone polishing points were used on the ceramic surface for manual polishing. Roughness was measured using a surface roughness tester. The roughness measurements were made along a distance of 2 mm on the sample surface and the speed of reading was 0.1 mm/s. Three measurements were taken for each sample. The data (μm) were statistically analyzed using analysis of variance (ANOVA) and Tukey's test (α = 0.05). Qualitative analysis was performed using scanning electron microscopy (SEM). The mean (± SD) roughness values obtained for GZ were: 1.1 ± 0.40 μm; 1.0 ± 0.31 μm; 1.6 ± 0.31 μm; and 2.2 ± 0.73 μm. For MP, the mean values were: 0.66 ± 0.13 μm; 0.43 ± 0.14 μm; 1.6 ± 0.55 μm; and 2.0 ± 0.63 μm. The mean roughness values were significantly affected by the ceramic type (P = 0.0001) and polishing technique (P = 0.0047). The SEM images confirmed the roughness data. The manually polished glass CAD/CAM ceramics promoted lower surface roughness than did the glazed feldspathic dental ceramics.
authors.affiliation: Department of Restorative Dentistry, Sao Paulo State University, Araraquara Dental School UNESP, Araraquara, Brazil.
authors.forename: Osmir Batista
authors.initials: OB
authors.lastname: Oliveira-Junior
authors.forename: Leonardo
authors.initials: L
authors.lastname: Buso
authors.forename: Fábio Hiroshi
authors.initials: FH
authors.lastname: Fujiy
authors.forename: Geraldo Henrique Leao
authors.initials: GH
authors.lastname: Lombardo
authors.forename: Fernanda
authors.initials: F
authors.lastname: Campos
authors.forename: Hugo Ramalho
authors.initials: HR
authors.lastname: Sarmento
authors.forename: Rodrigo Othavio Assuncao
authors.initials: RO
authors.lastname: Souza
mesh_terms: D000704:Analysis of Variance; D017076:Computer-Aided Design; D003775:Dental Polishing / Q000379:methods*; D003776:Dental Porcelain / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties
chemical_list: D003776:Dental Porcelain