Year : 2019

Volume : Volume 10

Issue : Issue 1s

Address for correspondence :
Dr. Lokesh Sunkala.
drlokeshs@gmail.com

Abstract

Background:  Bonding of zirconia crowns to the tooth and to the luting agent has been a topic of research since long time. Studies have been carried out in the past to evaluate the efficiency of conventional and adhesive luting agents for luting zirconia copings. But there was no unanimity in the conclusion. The present study was conducted in vitro for the comparative evaluation of the tensile bond strength of three cements namely zinc phosphate cement, glass ionomer cement and a self-adhesive resin cement used for the luting of zirconia copings to natural teeth and to characterize the mode of interfacial bond failure. Materials and method: A total of thirty extracted human molar teeth were mounted in auto polymerizing acrylic resin blocks. They were divided into three groups of 10 samples each namely Group A- Zirconia copings to be luted with zinc phosphate cement, B- Zirconia copings to be luted with glass ionomer cement, C- Zirconia copings to be luted with self-adhesive resin cement.  All the mounted teeth were prepared in a standardized manner to have a uniform configuration. Zirconia copings were then fabricated for each of the prepared tooth using ceramill CAD/CAM machine and luted with the respective luting agents. The samples were later subjected to tensile bond strength testing by universal testing machine. The results thus obtained were tabulated and subjected to statistical analysis by one-way analysis of variance (ANOVA) and post hoc tests. All the debonded samples were analyzed for their mode of failure using the criteria proposed by Johnson et al. Results and Conclusion: On comparison of the mean tensile bond strength of the three different luting agents, it was revealed that self-adhesive resin cement Group C, mean 3.9676 ± 0.38 Mpa demonstrated statistically significant higher tensile bond strength than glass ionomer cement Group B, mean 1.04004 ± 0.19 Mpa and zinc phosphate cement, Group A, mean 0.69359 ± 0.18 Mpa. The mode of interfacial bond failure was found to be in accordance with the tensile bond strength values obtained for all the three groups. Self-adhesive resin cement showed a predominantly cohesive mode of failure which corresponds well with the highest bond strength obtained for that group. Within the limitations of the study, it was found that self-adhesive resin cement had the highest tensile bond strength and cohesive mode of bond failure.

Keywords: Luting of zirconia copings, Self-adhesive resin cement, Tensile bond strength, Mode of bond failure.