Sealing Performance of Dual-cured Resin Cements

Objectives: To comparatively appreciate in vitro the quality of luting resin composite veneers using a dual-cured resin cement versus a dual-cured self-etch/self-adhesive resin cement. Methods: Twenty human permanent maxillary incisors, extracted due to their mobility (grade IV) were prepared for veneers with preservation of enamel margins. The veneers were made with poly-glass composite (belleGlass HP, Kerr). Teeth were randomly divided into 2 groups (n=10) and luting of veneers was accomplished following the manufacturer's instructions as follows: Group I, dual-cured resin cement (Nexus NX3, Kerr); Group II, dual-cured self-etch/self-adhesive resin cement (Maxcem Elite, Kerr). Teeth were thermocycled between 5⁰C and 55⁰C for 1000 cycles, immersed in 0.5% basic fuchsine solution for 24 hours and cut in a bucco-lingual plane using a water-cooled microtome in order to obtain a 1.5 mm section thickness at the middle of the mesio-distal dimension of the veneer. Die penetration along the tooth-cement (MTC) and cement-veneer (MCV) interface were evaluated with an inverted microscope (Olympus KC301, Olympus America Inc.) at 40x and microleakage values recorded (µm) using a Quick 3.0 software. For each interface microleakage values were referred to the total length of that interface (MTCr and MCVr) and data were subjected to statistical analysis by Student t and Mann-Whitney tests at a p<0.05 level of significance. Results: The results for MTCr were: Group I 0.03±0.03 and Group II 0.07±0.08 (p=0.4). The results of MCVr were: Group I 0.01±0.02 and no microleakage for Group II (p=0.5). In Group II we registered one total debonding during cutting process. Conclusion: With the margins of the veneers located in the enamel, no significantly differences were obtained between the two groups at both interfaces. However for the dual-cured self-etch/self-adhesive resin cement we registered one total debonding of the veneer, which may sugests the technique sensitivity of this luting material.