Effectiveness of two‐liquid silane primers on bonding sintered feldspathic porcelain with a dual‐cured composite luting agent

The purpose of the current study was to evaluate the effect of two-component ceramic primers on the bond strength of a composite material joined to a sintered porcelain material. Two sizes of porcelain discs (VMK 68; 10 and 8 mm in diameter by 2.5 mm thick) were ground (No. 1000 SiC), and surface-conditioned using one of the following systems: (i) unprimed, (ii) Liquid A of the Porcelain Liner M material (PLM-A), (iii) Liquid B of Porcelain Liner M (PLM-B), (iv) Liquids A and B of Porcelain Liner M (PLM-AB), (v) Liquid A of the Tokuso Ceramics Primer material (TCP-A), (vi) Liquid B of Tokuso Ceramics Primer (TCP-B) and (vii) Liquids A and B of Tokuso Ceramics Primer (TCP-AB). All specimens were bonded with the Bistite II dual-cured composite luting agent, and shear bond strengths were determined both after 24 h immersion in water and after subsequent thermocycling (4-60 degrees C, 1 min each, 20,000 cycles). Of the seven groups assessed, two groups (PLM-AB and TCP-AB) showed the greatest bond strength both before (30.7 MPa for PLM-AB and 29.7 MPa for TCP-AB) and after (19.7 MPa for PLM-AB and 22.4 MPa for TCP-AB) thermocycling (P < 0.05). No significant differences were found between the PLM-AB and TCP-AB groups regardless of the application of thermocycling (P > 0.05). It can be concluded that both of the acid-catalysed two-liquid ceramic primers showed superior bonding to the unhydrolysed single-liquid silane agents (PLM-B and TCP-A) when the feldspathic porcelain was bonded with the Bistite II luting composite.