title: Wear performance of substructure ceramics and veneering porcelains.
abstract: OBJECTIVE
  The aim of this in vitro study was to compare the two-body wear resistance of substructure zirconia and veneering porcelain versus steatite and human enamel antagonists, respectively.
  
  
  METHODS
  Two-body wear tests were performed in a chewing simulator with steatite and enamel antagonists (enamel cusps). A pin-on-block design with a vertical load of 50 N for 1.2 × 10(5) cycles; (f=1.6 Hz; lateral movement: 1mm, mouth opening: 2mm) was used for the wear test. For quantification of the wear resistance, wear tests were performed with standardized steatite spheres. Human enamel was used as a reference. Five zirconia ceramics and four veneering porcelains were investigated. One zirconia ceramic was tested with superficial glaze, which was applied after polishing or sandblasting, respectively. Surface roughness R(a) (SP6, Perthen-Feinprüf, G) and wear depth were determined using a 3D-Profilometer (Laserscan 3D, Willytec, G). SEM (Quanta FEG 400, FEI, USA) pictures were used for evaluating wear performance of both, ceramics and antagonists.
  
  
  RESULTS
  No wear was found for zirconia substructures. Veneering porcelain provided wear traces between 186.1±33.2 μm and 232.9±66.9 μm (steatite antagonist) and 90.6±3.5 μm and 123.9±50.7 μm (enamel). Wear of the steatite antagonists varied between 0.812±0.256 mm(2) and 1.360±0.321 mm(2) for zirconia and 1.708±0.275 mm(2) and 2.568±0.827 mm(2) for porcelain. Enamel generally showed wear, cracks or even fractures at the ridge, regardless whether opposed by zirconia or porcelain/glaze. Enamel was polished, when opposed to zirconia, or plowed, provoked and grinded, when opposed to porcelain/glaze.
  
  
  CONCLUSIONS
  The results of the wear test with steatite or enamel antagonists indicated no measurable wear on zirconia surfaces. Porcelain showed higher wear than zirconia, but comparable or lower wear than an enamel reference. Antagonistic wear against zirconia was found to be lower than wear against porcelain.
authors.affiliation: Department of Prosthetic Dentistry, Regensburg University Medical Center, D-93042, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Preis
authors.forename: Michael
authors.initials: M
authors.lastname: Behr
authors.forename: Carola
authors.initials: C
authors.lastname: Kolbeck
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hahnel
authors.forename: Gerhard
authors.initials: G
authors.lastname: Handel
authors.forename: Martin
authors.initials: M
authors.lastname: Rosentritt
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D001732:Bite Force; D002516:Ceramics / Q000737:chemistry; D003743:Dental Enamel / Q000648:ultrastructure; D045662:Dental Etching / Q000379:methods; D003775:Dental Polishing / Q000379:methods; D003776:Dental Porcelain / Q000737:chemistry*; D019554:Dental Restoration Wear; D003801:Dental Veneers; D006801:Humans; D008277:Magnesium Oxide / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017680:Potassium Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; C110711:vita omega; C499362:yttria stabilized tetragonal zirconia; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; D008277:Magnesium Oxide; D015019:Yttrium; C089766:steatite; D012822:Silicon Dioxide; D015040:Zirconium; C028541:zirconium oxide