title: Assessment of wear facets produced by the ACTA wear machine.
abstract: OBJECTIVE
  To investigate the use of a three-dimensional (3D) digital scanning method in determining the accuracy of the wear performance parameters of resin-based composites (RBCs) determined using a two-dimensional (2D) analogue methodology following in-vitro testing in an Academisch Centrum for Tandheelkunde Amsterdam (ACTA) wear machine.
  
  
  METHODS
  Specimens compatible with the compartments of the ACTA wear machine specimen wheel (n=10) were prepared from one commercial and four experimental RBCs. The RBC specimens were rotated against an antagonist wheel in a food-like slurry for 220,000 wear cycles. The mean wear depth was measured using the traditionally employed 2D and compared with the 3D profilometric (digital) techniques. Data were submitted to analyses of variance, Tukey's post hoc tests and Independent Samples Student's t-tests (where appropriate) at p<0.05.
  
  
  RESULTS
  The RBC rank achieved for mean wear depth calculations were similar whether the 2D or 3D techniques were employed. However, the mean wear depth values obtained from the 3D digital technique were significantly increased for two of the five RBC materials compared with the 2D methodology. The total volumetric wear data provided an assessment of the potential of the experimental RBC formulations for clinical usage.
  
  
  CONCLUSIONS
  The 3D technique allowed for the assessment of mean maximum wear depth and mean total volumetric wear which enables tribological analyses of the wear facet and therefore the wear mechanisms operative. Employing the 2D profile technique ranks RBC materials in terms of in-vitro wear performance.
  
  
  CONCLUSIONS
  Confidence in the wear volume measurements can only be achieved if the wear facet is analysed with sufficient resolution using a 3D digital measurement technique. However, the employment of 2D profilers is useful when screening potential new RBC formulations for the restoration of posterior dentition.
authors.affiliation: Section for Oral Rehabilitation, Dental Materials and Oral Diagnostics, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Benetti
authors.affiliation: Section for Oral Rehabilitation, Dental Materials and Oral Diagnostics, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Larsen
authors.affiliation: Materials Science Unit, Dublin Dental University Hospital, Lincoln Place, Trinity College Dublin, Ireland.
authors.forename: Adam H
authors.initials: AH
authors.lastname: Dowling
authors.affiliation: Materials Science Unit, Dublin Dental University Hospital, Lincoln Place, Trinity College Dublin, Ireland. Electronic address: garry.fleming@dental.tcd.ie.
authors.forename: Garry J P
authors.initials: GJ
authors.lastname: Fleming
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D019554:Dental Restoration Wear; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods; D008962:Models, Theoretical; D013499:Surface Properties; D057085:Tooth Wear
chemical_list: C090257:Foundation composite resin; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: ACTA wear machine; Resin-based composite; Wear depth and wear volume; Wear facet