Phytic Acid: A Novel Dentine Conditioning Agent for Glass Ionomer Cement Restorations: An In Vitro Scanning Electron Microscopic Study

Abstract

Background: Various dentin conditioners have been recommended to enhance the bond strength of glass ionomer cement (GIC) to dentin. The purpose of the in vitro study was to determine the efficacy of three dentin conditioners on the microshear bond strength of GIC and the failure patterns of the restoration, as well as the efficacy of removing the smear layer using a scanning electron microscope (SEM). Materials and Methods: Eighty healthy mandibular premolars were cleaned, isolated, and divided into four groups (n = 20). Flat coronal dentinal surfaces were accomplished by removing the occlusal surface of the crowns. Each group received the following treatment: group 1 with 10% polyacrylic acid; group 2 with 10% ethylenediaminetetraacetic acid (EDTA); group 3 with 1% phytic acid; and group 4 with no conditioning (control). High-strength Fuji IX GIC was applied to the dentin, and samples were thermocycled and de-bonded with a crosshead speed of 0.5 mm/min employing a shear force. A stereomicroscope and a SEM were used to examine the dentin surface at magnifications of 2000× and 5000×. One-way analysis of variance (ANOVA), Tukey’s post hoc test, and Chi-squared test were used to assess data on microshear bond strength, smear layer removal, and failure modes. Results: The bond strength of group 4 was statistically highly significant (P ≤ 0.001) compared to the other groups. However, the differences between groups 2 and 3 were insignificant. Mixed pattern of failure was the least in group 3 (IP6). In group 3, the SEM photomicrograph revealed open dentinal tubules with complete removal of the smear layer. Conclusion: The results of the present study affirm that phytic acid enhances the bond strength of GIC restorations and removal of smear layer to a level comparable to EDTA as a dentin conditioner.