title: Enamel wear opposing different surface conditions of different CAD/CAM ceramics.
abstract: OBJECTIVE
  The aim of this study was to evaluate bovine enamel wear opposed to four different ceramic substrates (CEREC) in the glazed and polished conditions.
  
  
  METHODS
  Sixty-three ceramic (IPS Empress CAD, Paradigm C, Vitablocs Mark II) and fourteen composite resin (MZ100) styli were prepared. Ceramics were subdivided into three surface conditions (n = 7), unpolished, polished, and glazed, and the composite resin (n = 7) into unpolished and polished. All styli were used as wear antagonists opposing bovine enamel blocks (8 mm × 9 mm) in an oral wear simulator. Wear tests were conducted at 30 N abrasion and 70 N attrition forces applied at 1.7 Hz for 5,000 simulated mastication cycles. Abrasion and attrition wear were evaluated using an automatic profilometer. Statistical analyses were conducted using Tukey's B rank order test, P = .05.
  
  
  RESULTS
  For bovine enamel opposing glazed Vitablocs, abrasion and attrition wear showed a volume loss significantly higher than bovine enamel opposing polished Vitablocs (P < .05). For attrition wear, bovine enamel opposing glazed Vitablocs and untreated Paradigm C showed a volume loss higher than bovine enamel opposing the other ceramic conditions.
  
  
  CONCLUSIONS
  Abrasion and attrition wear of bovine enamel opposing antagonist ceramic was affected according to the ceramic surface condition and the ceramic material. Antagonistic wear against the studied ceramic materials and conditions exhibited wear rates within the range of normal enamel. In addition, the glaze layer presented as a protection, exhibiting fewer cracks and less loss of material on the ceramic surface.
authors.forename: Sheila Pestana
authors.initials: SP
authors.lastname: Passos
authors.forename: Anderson P
authors.initials: AP
authors.lastname: de Freitas
authors.forename: Gabriel
authors.initials: G
authors.lastname: Iorgovan
authors.forename: Amin Sami
authors.initials: AS
authors.lastname: Rizkalla
authors.forename: Maria Jacinta
authors.initials: MJ
authors.lastname: Santos
authors.forename: Gildo Coelho
authors.initials: GC
authors.lastname: Santos Júnior
mesh_terms: D002516:Ceramics; D003188:Composite Resins; D003764:Dental Materials; D006801:Humans; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D057085:Tooth Wear
chemical_list: D003188:Composite Resins; D003764:Dental Materials