title: The effect of thermal cycling on metal-ceramic bond strength.
abstract: OBJECTIVE
  The aim was to evaluate the effect of thermal cycling on the metal-ceramic bond strength.
  
  
  METHODS
  Four different noble metal alloys were used. Specimens for the crack initiation test according to ISO 9693 were prepared to assess metal-ceramic bond strength (n=10). The metal substrates were either air-borne particle abraded or polished prior to veneering. Bond strength was measured after veneering or after 6000 thermal cycles. With one alloy in addition long-term thermal cycling with 15,000 and 50,000 cycles was carried out. Statistical analysis was performed with one-way ANOVA followed by a post hoc Bonferroni test.
  
  
  RESULTS
  Polished metal substrates showed a significantly lower bond strength compared to the air-borne particle abraded substrates. Treatment with 6000 thermal cycles did not significantly reduce the bond strength. Long-term thermal cycling resulted in an exponential decrease of bond strength for both polished and air-borne particle abraded specimens.
  
  
  CONCLUSIONS
  Air-borne particle abrasion significantly increases metal-ceramic bond strength. Thermal cycling of metal-ceramic composites results in an exponential decrease of bond strength. The crack initiation test is a sensitive method for assessing the metal-ceramic bond strength.
authors.affiliation: Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, Center for Dental and Oral Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland. jens.fischer@zzmk.uzh.ch
authors.forename: Jens
authors.initials: J
authors.lastname: Fischer
authors.forename: Christoph
authors.initials: C
authors.lastname: Zbären
authors.forename: Bogna
authors.initials: B
authors.lastname: Stawarczyk
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
mesh_terms: D000465:Algorithms; D000537:Aluminum Oxide / Q000737:chemistry; D001840:Dental Bonding; D003735:Dental Casting Technique; D045662:Dental Etching / Q000379:methods; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D055119:Elastic Modulus; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature
chemical_list: D006047:Gold Alloys; D016876:Metal Ceramic Alloys; C096478:Omega Dental Ceramic; D003776:Dental Porcelain; D010984:Platinum; D010165:Palladium; D000537:Aluminum Oxide