Effect of Silanization on Microtensile Bond Strength of Different Resin Cements to a Lithium Disilicate Glass Ceramic

This study evaluated the influence of a silane-coupling agent on the bond strength of a self-adhesive cement and a conventional resin cement to a lithium disilicate glass ceramic.

A total of eight ceramic blocks were fabricated and divided into four groups (n = 2). In groups 1 and 3, ceramic surfaces were etched with hydrofluoric acid 10% for 20 seconds, rinsed for 30 seconds, and air-dried. One layer of a silane agent was applied onto all ceramic specimens and air-dried for 30 seconds. In groups 2 and 4, ceramic surfaces were etched with hydrofluoric acid, rinsed, and air-dried without application of the silane-coupling agent. The ceramic blocks were bonded to a block of composite with a self-adhesive resin cement or with a conventional resin cement, according to the manufacturer's instructions. After 24 hours in distilled water at 37°C, the specimens were sectioned perpendicular to the bonding interface area to obtain beams with a bonding area of 0.8 mm(2) and submitted to a microtensile bond strength test at a crosshead speed of 0.5 mm/min. Data were statistically analyzed with one-way analysis of variance and the Games-Howell post hoc test (p = 0.05). Fractured specimens were examined under optical microscopy at 40x magnification.

Silanization resulted in higher microtensile bond strength compared to groups without silane. No significant differences were found between the conventional resin cement and the self-adhesive resin cement with silane agent (p = 0.983), and without silane agent (p = 0.877).

Silanization appears to be crucial for resin bonding to a lithium disilicate-based ceramic, regardless of the resin cement used. The self-adhesive resin cement performed as well as the conventional resin cement.

Applying one layer of a silane-coupling agent after etching the ceramic surface with hydrofluoric acid 10% enhanced the bond strength between resin cements and a glass ceramic.