Comparison of shear bond strength of different resin cements to ceramic and dentin

Abstract

To evaluate the effect of different resin cements and dentin surface treatment methods on shear bond strength between glass ceramic and human dentin. Freshly extracted non-carious human premolars were collected to prepare flat mesial and distal dentin surface with diamond bur. Besides, ceramic discs (3 mm in diameter, 3 mm in height) were fabricated with IPS e. max Press ingots. All samples were randomly divided into five groups, sixteen specimens each. Ceramic discs were cemented on dentin surface using one of the five resin cements [Group A (Variolink II), Group B (Multilink Automix), Group C (Multilink Sprint), Group D (Rely X Unicem) and Group E (BisCem)] respectively. Half of the specimens were stored in water 37 degrees C for 24 h and the other half were additionally thermocycled for 5000 times (5 degrees C/55 degrees C) before shear bond strength test. Dentin bonding surface and transverse plane were examined with a scanning electronic microscope. Group A showed the highest bond strength before thermocycling [(22.3 +/- 3.9) MPa], and the bond strength of Group B [(18.1 +/- 3.5) MPa] was lower than that of Group A (P < 0.05). Group E [(11.7 +/- 4.2) MPa], Group C [(11.3 +/- 3.6) MPa] and Group D [(14.1 +/- 2.3) MPa] had the lowest bond strength. After thermocycling, Group A still showed the highest bond strength [(17.8 +/- 2.3) MPa]. The bond strength of Group B [(14.4 +/- 3.5) MPa] and Group D [(13.2 +/- 2.5) MPa] were lower than that of Group A. Group E [(8.9 +/- 3.2) MPa] and Group C [(7.0 +/- 2.4) MPa] showed the lowest bond strength. The bond strength of all groups decreased notably after thermocycling except Group E and Group D. The resin cement based on etch-rinsing bonding system has higher bond strength to dentin than those based on self-etch bonding system and self-adhesive resin cements.