title: Influence of the bonder on the adhesion of porcelain to machined titanium as determined by the strain energy release rate.
abstract: OBJECTIVE
  To determine the adhesion at the titanium-porcelain interface using a fracture mechanics approach, and to investigate the bonding mechanism using SEM.
  
  
  METHODS
  Specimens of five different titanium-porcelain and one base metal-porcelain bonding systems were prepared for a four-point bending interfacial delaminating test on a universal testing machine. The pre-cracked specimen was subjected to load and the strain energy release rate (G, J/m(2)) was calculated from the critical load to induce stable crack extension in each system. The interface for the various materials was investigated in an SEM and compared.
  
  
  RESULTS
  The titanium-porcelain with Gold Bonder showed the highest G-value (72.39+/-13.21J/m(2)) among the groups whilst titanium-porcelain with cross-cut-bur preparation showed the lowest (5.78+/-1.39J/m(2)). The former was significantly higher than that of Wiron 99 (base-metal, BEGO, Germany) porcelain (40.01+/-6.67J/m(2)), a clinically accepted bonding system for many years. The G-values of porcelain fused to titanium-Rocatec, titanium-sandblasted and/or titanium-GC-Bonder were 10.81+/-1.49, 12.64+/-3.01 and 35.74+/-5.20J/m(2), respectively. SEM images of the interface fracture crack path for the different bonders enabled the mechanisms responsible for the differences in strain energy release rates to be appreciated.
  
  
  CONCLUSIONS
  The strain energy release rate (G) of titanium-porcelain with a Gold Bonder interface layer was highest among the five different systems.
authors.affiliation: Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
authors.forename: M J
authors.initials: MJ
authors.lastname: Tholey
authors.forename: J N
authors.initials: JN
authors.lastname: Waddell
authors.forename: M V
authors.initials: MV
authors.lastname: Swain
mesh_terms: D000269:Adhesives; D001840:Dental Bonding / Q000379:methods*; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D016876:Metal Ceramic Alloys; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D013499:Surface Properties; D013816:Thermodynamics; D014025:Titanium
chemical_list: D000269:Adhesives; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D014025:Titanium