title: Validation of enamel erosion in vitro.
abstract: OBJECTIVE
  Many tools are available to quantify dental erosion, but each technique has its own inherent disadvantages. This study aims to validate the use of quantitative light-induced fluorescence (QLF) and non-contacting surface profilometry compared to the gold standard transverse microradiography (TMR) for the quantification of enamel erosion in vitro.
  
  
  METHODS
  This was an in vitro laboratory based study. 60 bovine incisors were divided into 6 groups of 10. Each tooth's labial surface was completely varnished except for a window of enamel approximately 3mmx5mm. Each was baseline imaged with QLF and non-contacting surface profilometry before being subjected to an erosive solution (pH 3.4) for up to 36h. The lesions were imaged using non-contacting surface profilometry and QLF, sectioned and analysed with TMR. Correlation coefficients were calculated to assess the validity of the methods of measurement as compared to TMR.
  
  
  RESULTS
  A range of lesion severities resulted. Mineral loss measured as DeltaQ (QLF) and step height (profilometry), was recorded and confirmed by TMR. A correlation was found between DeltaZ (TMR) and profilometry lesion depth of r=0.648 (p<0.001). A poorer correlation was found between DeltaZ and DeltaQ: r=0.217 (p=0.096).
  
  
  CONCLUSIONS
  Profilometry lesion depth and DeltaZ correlated significantly. Both methods allow for quantification of erosive crater depth. QLF correlated poorly with DeltaZ, but is useful for measuring subsurface loss of mineralisation. TMR is valuable but is destructive and can only be used in vitro. Currently only QLF can be used in vivo. Advances in these technologies may allow the development of non-destructive in vivo measurements of mineral loss, combining the positive features of each measurement method.
authors.affiliation: Liverpool University Dental Hospital, Pembroke Place, United Kingdom. victoria.elton@man.ac.uk
authors.forename: Victoria
authors.initials: V
authors.lastname: Elton
authors.forename: Lee
authors.initials: L
authors.lastname: Cooper
authors.forename: Susan Mary
authors.initials: SM
authors.lastname: Higham
authors.forename: Neil
authors.initials: N
authors.lastname: Pender
mesh_terms: D000143:Acids / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects / Q000473:pathology*; D005453:Fluorescence; D007091:Image Processing, Computer-Assisted; D007368:Interferometry / Q000379:methods; D008027:Light; D008852:Microradiography; D015203:Reproducibility of Results; D013499:Surface Properties; D014077:Tooth Erosion / Q000473:pathology*
chemical_list: D000143:Acids