Durability of the dual-cure resin cement/ceramic bond with different curing strategies.

PURPOSE

To evaluate the effects of different curing strategies on the durability of the dual-cure resin cement/ceramic bond.

MATERIALS AND METHODS

Machinable ceramic blanks were cut into pairs of 3-mm-thick slices, which were then polished using wet 600-grit SiC paper. The slices were silanated using one of two ceramic priming systems: (1) Tokuso Ceramic Primer (TCP), and (2) K-etchant/Clearfil Liner Bond 2V Primer (LB2V)/Porcelain Bond Activator (PBA), and bonded with one of two dual-cure resin cements (Bistite II, Panavia F), to make four experimental groups. Each group was subjected to one of three curing strategies: (1) no light, (2) 20 s light exposure from one direction, and (3) 20 s light exposure from each of six directions. After 24 h water storage at 37 degrees C, 0.7-mm-thick slabs were produced by serially sectioning perpendicular to the bonded interface. Immediately thereafter, and after one and six weeks of water storage, two slabs were randomly selected and sliced into beams for the microtensile bond strength (microTBS) test. Data were evaluated using Kruskal-Wallis and Wilcoxon rank tests (p < 0.05), and failure modes determined using a laser-scanning confocal microscope.

RESULTS

After priming with TCP, microTBS of Bistite II significantly increased over time when exposed to light, whereas the microTBS of the no-light group significantly decreased over time (p < 0.05). After priming with TCP, microTBS of Panavia F increased over time, and after 6 weeks water storage, there were no significant differences in microTBS between the no-light and light-exposed groups (p > 0.05). Increases in microTBS were associated with increases in the number of cohesive failures in resin cement. After phosphoric acid treatment, priming with LB2V/PBA, and light exposure, microTBS of Bistite II remained stable, whereas that of Panavia F significantly reduced over time (p < 0.05). The microTBS of no-light LB2V/PBA groups reduced significantly over time (p < 0.05).

CONCLUSION

The durability of the dual-cure resin cement/ceramic bond depends upon the multicomponent ceramic primer and the amount of light received by the resin cement.