Shear Bond strength of self adhesive cements to ceramics

Objectives: To measure the adhesive bond strength under microshear between leucite-based machinable ceramic disks cemented with a self-etching cement and two types of self-adhesive cements.

Methods: One ceramic (IPS Empress CAD, Ivoclar Vivadent AG), two self-self-adhesive cements (RelyX U100, 3M ESPE, and Maxcem, Kerr Corp,)  and a self-etching cement (Panavia F, Kuraray) were used. Six groups were formed according to the luting agent and the ageing process. Half of the specimens were subjected to the test immediately after the luting procedure and the other half was stored in a moist environment at 37 °C for 24h and subjected to 500 thermocycles (5 to 55ºC). The specimens were then subjected to microshear bond strength test in an universal test machine (Instron, Model 4444, Instron, Canton, MA, USA) with a crosshead speed of 0.5mm/min until failure. The type of failure was determined using an optical microscope. The adhesive bond strength was calculated (MPa) and statistically analyzed through two-way ANOVA (α = 0.05) and Bonferroni test (α = 0.05).

Results: The mean values of the specimens cemented with RelyX U100 were similar (p=1.00), but different from those obtained for the other materials, regardless of the thermocycling (p<0.001). The specimens cemented with Maxcem, without thermocycling, reached similar mean bond strengths in comparison to Panavia, with or without thermocycling (p=1.00). All specimens cemented with Maxcem and thermocycled failed before testing, ie, this group obtained the lowest values (p<0.001). Finally, all specimens cemented with Panavia reached similar strength values (p=0.72).

Conclusions: The self-adhesive cement (RelyX U100) reached the highest bond strength values, for both ageing conditions.