Bond strength between resin cements and glass-ceramic: influence of silane incorporation into the adhesive system — an in vitro study

Background This study evaluated the influence of eliminating silane as an additional step in a cementation system combining a universal adhesive and a universal resin cement for bonding leucite-reinforced ceramic to dentin. Methods Extracted third molars ( n = 21) were prepared into disc-shaped specimens, exposing the dentin surface. Ceramic slices were bonded to the substrate according to three adhesive protocols: a control group using a universal adhesive and a multi-purpose resin cement with silane as an additional step; a second group using a new universal adhesive and a universal resin cement with silane as an additional step; and a third group using the new adhesive system without silane application. After luting, specimens were sectioned into 1 mm² sticks. Half were tested immediately, and the other half were aged in distilled water for six months before testing. Microtensile bond strength, biaxial flexural strength, and contact angle tests were conducted. Results Immediate bond strength was similar across groups, but aging reduced values in all groups, with the group without silane showing the greatest reduction and highest number of pre-test failures. Conclusions Under the conditions tested, eliminating the additional silane application did not affect immediate bond strength; however, after aging, the simplified protocol showed less favorable performance, characterized by reduced bond strength values and a higher incidence of pre-test failures.