title: Three-body wear associated with three ceramics and enamel.
abstract: BACKGROUND
  Wear of human enamel is a clinical concern whenever opposing teeth need to be restored using ceramic restorations.
  
  
  OBJECTIVE
  This in vitro study investigated wear of human enamel and 3 dental ceramics: a conventional porcelain (Vitadur Alpha), a low-fusing hydrothermal ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II) in a 3-body wear test.
  
  
  METHODS
  Thirty pairs of tooth-ceramic specimens were tested in a dental wear machine, under a standard load (40 N), rate (80 cycles/minute), and for 25,000 cycles in a simulated food slurry medium. Amount of wear was determined by measuring the height loss of the tooth and depth of wear track of the ceramic materials. Analysis of variance (ANOVA) was used to analyze the data, followed by Bonferroni multiple comparisons method to produce sets of simultaneous 95% confidence intervals.
  
  
  RESULTS
  ANOVA revealed significant differences between the groups for both enamel wear (P =. 002) and ceramic wear (P <.001). Further comparisons (95% CI significance level) revealed that the difference in enamel wear produced by Alpha porcelain and Duceram-LFC ceramic material was not statistically significant, whereas that produced by Vita Mark II ceramic was significantly less. Vita Mark II ceramic was significantly more resistant to wear than Alpha porcelain and Duceram-LFC ceramic. Furthermore, Alpha porcelain was significantly more resistant to wear than Duceram-LFC ceramic.
  
  
  CONCLUSIONS
  The abrasiveness of Alpha porcelain and Duceram-LFC ceramic was similar, yet both were significantly more abrasive than Vita Mark II ceramic. In addition, Vita Mark II was the most wear-resistant ceramic and Duceram-LFC ceramic the least resistant.
authors.affiliation: Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. hiyasat@just.edu.jo
authors.forename: A S
authors.initials: AS
authors.lastname: al-Hiyasat
authors.forename: W P
authors.initials: WP
authors.lastname: Saunders
authors.forename: G M
authors.initials: GM
authors.lastname: Smith
mesh_terms: D000704:Analysis of Variance; D016001:Confidence Intervals; D003743:Dental Enamel / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D013499:Surface Properties; D019217:Tooth Attrition / Q000209:etiology*
chemical_list: C095718:Duceram; C082340:Vita Mark II; D003776:Dental Porcelain