Purpose: To compare the strength of bond of belleGlass Indirect Composite to both enamel and dentin using 4 resin cements with bonding agent (Multilink, Nexus, Panavia, RelyX ARC), 1 self adhesive resin cement without bonding agent (RelyX Unicem), and 1 resin modified glass ionomer luting cement (RelyX Luting Plus).

Material and Methods: 96 specimens of freshly extracted teeth were mounted in resin and ground to expose 48 enamel and 48 superficial dentin surfaces. The surface was polished with 600 grit SiC discs. Each adhesive system was used according to manufacturer's directions. Prior to bonding, the belleGlass Indirect Composite material was molded and cured in the shape of inverted truncated cones with a 3 mm diameter at the bonding surface and 5 mm at the top of the cone, then microetched. 8 specimens were used for each condition. After bonding, specimens were kept in water at 37^oC for 24 hours. They were then debonded in tension using an instron at a cross-head speed of 0.5 mm/min.

Results: RelyX ARC to enamel and dentin and Nexus to enamel displayed the highest bond strengths.

Conclusion: When bonding indirect composites to enamel and/ or dentin a total etch/ bonded cement should be used for the best bond strengths.

Table: Bond strength of indirect composite bonded to human enamel and dentin using six cements.

Cement Enamel Dentin

ARC 9.5 (6.2)^aA 8.6 (4.8)^A

LP 1.1 (0.9)^cB 0.4 (0.4)^cB

ML 5.5 (2.3)^b 0.4 (0.3)^c

NX 7.8 (4.1)^ab 2.8 (2.4)^ab

PV 2.7 (1.5)^c 1.1 (1.1)^bc

UN 5.9 (3.1)^b 4.2 (4.7)^a

*Means (n=8) with standard deviations in parentheses. Fisher's PLSD intervals for comparisons of means at the 0.05 level of significance among cements and between enamel and dentin were 2.3 and 1.3 MPa, respectively. Means with the same superscripted letters are statistically the same.