title: Clinical and laboratory surface finishing procedures for zirconia on opposing human enamel wear: A laboratory study.
abstract: OBJECTIVE
  To investigate the effect of laboratory and clinical finishing procedures for zirconia on antagonistic enamel wear.
  
  
  METHODS
  Forty-eight yttria-tetragonal partially stabilised zirconia (Y-TZP) specimens were prepared and divided into four groups according to their surface preparation: laboratory polished (LP); laboratory polished and glazed (G); clinically adjusted (CA); and clinically adjusted and repolished (CAR). Enamel opposing enamel was used as a control. Pre-testing surface roughness for each group was determined using contact profilometry. Two-body wear resistance tests were conducted using a masticatory simulator. Enamel specimens were subjected to 120,000 cycles in distilled water (frequency 1.6 Hz, loading force of 49 N). Volumetric and vertical enamel losses were measured by superimposition of pre- and post-testing images using a three-dimensional laser scanner and software analysis. Scanning electron microscopy was used for qualitative surface analysis of pre- and post-testing zirconia and enamel surfaces. One-way ANOVA and multiple comparisons with Bonferroni corrections were used for statistical analysis at a significance level of α=0.05.
  
  
  RESULTS
  There was no statistical difference in volumetric and vertical enamel loss between CAR, G and LP. CAR produced statistically significantly less volumetric enamel loss compared with CA and control, and statistically significantly less vertical enamel loss compared with CA. Volumetric and vertical enamel loss were highly correlated in all groups.
  
  
  CONCLUSIONS
  Enamel wear by clinically ground zirconia is comparable to that of opposing enamel surfaces and greater than clinically repolished zirconia. Repolishing of zirconia restorations following clinical adjustment with diamond burs is effective in reducing antagonistic enamel wear.
authors.affiliation: Westmead Centre for Oral Health, Faculty of Dentistry, University of Sydney, Westmead, NSW, Australia. Electronic address: b.j.chong@gmail.com.
authors.forename: Bevan J
authors.initials: BJ
authors.lastname: Chong
authors.affiliation: Westmead Centre for Oral Health, Faculty of Dentistry, University of Sydney, Westmead, NSW, Australia. Electronic address: arun.thangavel1@gmail.com.
authors.forename: Arun K
authors.initials: AK
authors.lastname: Thangavel
authors.affiliation: WYSIWYG 3D, Unit 1/22 Norman Street, Peakhurst, Sydney, NSW 2210, Australia. Electronic address: shane@wysiwyg3d.com.au.
authors.forename: Shane B
authors.initials: SB
authors.lastname: Rolton
authors.affiliation: Westmead Centre for Oral Health, Faculty of Dentistry, University of Sydney, Westmead, NSW, Australia. Electronic address: mguazzato@yahoo.com.au.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Guazzato
authors.affiliation: Westmead Centre for Oral Health, Faculty of Dentistry, University of Sydney, Westmead, NSW, Australia. Electronic address: iven.klineberg@sydney.edu.au.
authors.forename: Iven J
authors.initials: IJ
authors.lastname: Klineberg
mesh_terms: D003743:Dental Enamel / Q000187:drug effects*; D006801:Humans; D007753:Laboratories; D008422:Materials Testing; D055595:Mechanical Phenomena; D013499:Surface Properties; D057085:Tooth Wear / Q000139:chemically induced* / Q000517:prevention & control*; D015040:Zirconium / Q000009:adverse effects*
chemical_list: D015040:Zirconium; C028541:zirconium oxide
keywords: Ceramic; Enamel; Surface finish; Tooth wear; Zirconia