title: Antagonist wear of three CAD/CAM anatomic contour zirconia ceramics.
abstract: BACKGROUND
  Little clinical information exists on the antagonist wear of anatomic contour zirconia crowns.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the 2-body wear of antagonists for 3 computer-aided design and computer-aided manufacturing (CAD/CAM) anatomic contour zirconia ceramics and veneering porcelain when opposing natural human enamel.
  
  
  METHODS
  Zirkonzahn Y-TZP (polished zirconia, zirconia with staining, zirconia with staining and glazing), Acucera Y-TZP, Wieland Y-TZP, and Noritake feldspathic ceramic were tested (6 groups). Eight disk-shaped specimens 15 mm in diameter and 5 mm thick were prepared for each group. Forty-eight specimens were fabricated for a wear test against maxillary premolars without caries or previous restorations with 240 000 masticatory cycles in a masticatory simulator. Before the experiment, the surface roughness of each ceramic was measured with a nanosurface 3-dimensional (3D) optical profiler. The surface of the specimens was observed at 50× and 1000× magnification with a field emission scanning electron microscope (FE-SEM) before and after the experiment. The data obtained were statistically analyzed by 1-way ANOVA and the Tukey test for post hoc analysis (α=.05).
  
  
  RESULTS
  The SEM observations of each group revealed fine bubbles and porous surfaces in the Noritake feldspathic ceramic group, whereas the polished Zirkonzahn Y-TZP group, Acucera Y-TZP group, and Wieland Y-TZP group had smooth surfaces. The surface roughness of Zirkonzahn Y-TZP after staining and glazing was significantly greater than that of any other groups (P<.01). The tooth opposing the polished Zirkonzahn Y-TZP group demonstrated the least wear (1.11 ± 0.51 mm³), while Zirkonzahn Y-TZP with staining and glazing produced the greatest enamel wear (3.07 ± 0.98 mm³) among the zirconia groups. The Noritake feldspathic ceramic group showed significantly more antagonistic tooth wear than other groups (P<.05).
  
  
  CONCLUSIONS
  The antagonist wear of 3 CAD/CAM anatomic contour zirconia ceramics was significantly less than the Noritake veneering ceramic because the surface character of Y-TZP is relatively uniform and homogeneous. Zirkonzahn Y-TZP with staining and glazing was significantly more abrasive than the other zirconia specimens tested. However, it was less abrasive than the Noritake veneering ceramic.
authors.affiliation: Graduate student, Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Korea.
authors.forename: Ji-Hee
authors.initials: JH
authors.lastname: Park
authors.affiliation: Professor, Department of Prosthodontics, School of Dentistry, Dental 4D Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Sangwon
authors.initials: S
authors.lastname: Park
authors.affiliation: Professor, Department of Materials Science and Engineering, College of Engineering, Chonnam National University, Gwangju, Korea.
authors.forename: Kwangmin
authors.initials: K
authors.lastname: Lee
authors.affiliation: Assistant Professor, Department of Prosthodontics, School of Dentistry, Dental 4D Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Kwi-Dug
authors.initials: KD
authors.lastname: Yun
authors.affiliation: Assistant Professor, Department of Prosthodontics, School of Dentistry, Dental 4D Research Institute, Chonnam National University, Gwangju, Korea. Electronic address: mcnihil@jnu.ac.kr.
authors.forename: Hyun-Pil
authors.initials: HP
authors.lastname: Lim
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D001732:Bite Force; D003116:Color; D017076:Computer-Aided Design; D003743:Dental Enamel / Q000648:ultrastructure; D003775:Dental Polishing / Q000379:methods; D003776:Dental Porcelain / Q000737:chemistry*; D019554:Dental Restoration Wear; D003801:Dental Veneers; D006358:Hot Temperature; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D017680:Potassium Compounds / Q000737:chemistry; D013499:Surface Properties; D057085:Tooth Wear / Q000473:pathology*; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; C016447:feldspar; D015019:Yttrium; D015040:Zirconium