title: Comparative strength of metal-ceramic and metal-composite bonds after extended thermocycling.
abstract: The relative strengths of ceramic-to-metal and composite-to-metal bonds were compared after prolonged thermocycling. A total of 104 cast discs were produced from a gold alloy (Pontor LFC). A ceramic material (Duceragold) was fused to 24 discs to assess the strength of the metal-ceramic bond. An indirect composite material (New Metacolor Infis) was bonded to the remaining discs after surface preparation by Rocatec tribochemical coating, tin plating and priming with a phosphate conditioner [10-methacryloyloxydecyl dihydrogen phosphate (MDP), Cesead II], priming with a thione conditioner (V-Primer) or no treatment (unprimed control). Shear bond strengths were determined before and after thermocycling at 20,000 and 100,000 cycles. Pre-thermocycling bond strengths were ranked in the order: metal-ceramic (40.5 MPa); Rocatec treatment (33.1 MPa) and tin plating-MDP (31.0 MPa); V-Primer (20.9 MPa); and control (11.9 MPa). The bond strengths of the first three groups were not significantly different after 20,000 thermocycles, whereas those of the V-Primer and control groups were significantly reduced. After extended thermocycling (100,000 cycles) the metal-ceramic group had the highest mean shear bond strength (28.5 MPa; P < 0.05), followed by the Rocatec (23.9 MPa) and tin plating-MDP (22.1 MPa) groups. The metal-ceramic bond was the most durable, although its strength was reduced by 29.6% after extended thermocycling. On the basis of these results, we recommend the Rocatec and tin plating-MDP systems for composite-to-metal bonding. Metal-ceramic bonding, however, is superior to metal-composite bonding within the limitation of the current experiment.
authors.affiliation: Department of Fixed Prosthodontics and Oral Rehabilitation, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shimoe
authors.forename: N
authors.initials: N
authors.lastname: Tanoue
authors.forename: H
authors.initials: H
authors.lastname: Yanagida
authors.forename: M
authors.initials: M
authors.lastname: Atsuta
authors.forename: H
authors.initials: H
authors.lastname: Koizumi
authors.forename: H
authors.initials: H
authors.lastname: Matsumura
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D006047:Gold Alloys / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing / Q000379:methods; D033081:Shear Strength; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D006047:Gold Alloys; C076811:Rocatec; D003776:Dental Porcelain