title: Quantification of tooth wear: conventional vs new method using toolmakers microscope and a three-dimensional measuring technique.
abstract: OBJECTIVE
  This study aimed to evaluate the reliability of a new CAD-CAM Laser scanning machine in detection of incisal tooth wear through a 6-month period and to compare the accuracy of using this new machine against measuring tooth wear using tool maker microscope and conventional tooth wear index.
  
  
  METHODS
  Twenty participants (11 males and 9 females, mean age=22.7 years, SD=2.0) were assessed for incisal tooth wear of lower anterior teeth using Smith and Knight clinical tooth wear index (TWI) on two occasions, the study baseline and 6 months later. Stone dies for each tooth were prepared and scanned using the CAD-CAM Laser Cercon System (Cercon Smart Ceramics, DeguDent, Germany). Scanned images were printed and examined under a toolmaker microscope (Stedall-Dowding Machine Tool Company, Optique et Mecanique de Precision, Marcel Aubert SA, Switzerland) to quantify tooth wear and then the dies were directly assessed under the microscope to measure tooth wear. The Wilcoxon Signed Ranks Test was used to analyse the data.
  
  
  RESULTS
  TWI scores for incisal edges were 0, 1, and 2 and were similar at both occasions. Scores 3 and 4 were not detected. Wear values measured by directly assessing the dies under the tool maker microscope (range=517-656microm, mean=582microm, and SD=50) were significantly more than those measured from the Cercon digital machine images (range=132-193microm, mean =165microm, and SD=27) and both showed significant differences between the two occasions.
  
  
  CONCLUSIONS
  Measuring images obtained with Cercon digital machine under tool maker microscope allowed detection of wear progression over the 6-month period. However, measuring the dies of worn dentition directly under the tool maker microscope enabled detection of wear progression more accurately. Conventional method was the least sensitive for tooth wear quantification and was unable to identify wear progression in most cases.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, The University of Jordan, Amman 11942, Jordan. alomirim@yahoo.co.uk
authors.forename: Mahmoud K
authors.initials: MK
authors.lastname: Al-Omiri
authors.forename: Rousan
authors.initials: R
authors.lastname: Harb
authors.forename: Osama A
authors.initials: OA
authors.lastname: Abu Hammad
authors.forename: Philip-John
authors.initials: PJ
authors.lastname: Lamey
authors.forename: Edward
authors.initials: E
authors.lastname: Lynch
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Clifford
mesh_terms: D000328:Adult; D017076:Computer-Aided Design; D003481:Cuspid / Q000473:pathology; D003743:Dental Enamel / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000473:pathology; D007834:Lasers; D008297:Male; D008853:Microscopy / Q000295:instrumentation*; D003765:Models, Dental; D015203:Reproducibility of Results; D019237:Tooth Cervix / Q000473:pathology; D057085:Tooth Wear / Q000175:diagnosis* / Q000473:pathology; D055815:Young Adult