Effects of the Contents of Various Solvents in One-step Self-etch Adhesives on Shear Bond Strengths to Enamel and Dentin.

AIM

The aim of this study was to evaluate the shear bond strengths (SBSs) of one-step self-etch adhesives containing different co-solvents to enamel and dentin and to determine the failure modes of tested specimens.

MATERIALS AND METHODS

Two hundred and forty ( = 240) sound human molars were used. The buccal surfaces of each tooth were ground and polished to obtain flat enamel surfaces ( = 120) or to expose the underlying dentin ( = 120). The specimens with exposed enamel or dentin were randomly divided into four main groups ( = 30) according to the one-step self-etch adhesives used: Bond-1 SF, OptiBond All-In-One, G-aenial, and Single Bond Universal adhesive. All the main groups were then subdivided into two subgroups (control and thermocycling subgroups) ( = 15). After bonding procedures, a composite restoration (Filtek Z250) was applied in a vinyl tube and condensed against the cured adhesive bonding agent, to form a resin cylinder. The specimens were stored in distilled water at 37°C for 24 hours (control and thermocycling subgroups), followed by thermocycling (5-55°C/5,000 cycles + storage in artificial saliva for 2 weeks) (thermocycling subgroup). They were subjected to SBS testing in a universal testing machine at a crosshead speed of 0.5 mm/minute. After being shear-tested, all fractured samples were examined by means of a Hirox Digital Microscope at 50× magnification for failure analysis. The data were analyzed by one-way analysis of variance followed by Tukey's analysis at a value of ≤0.05.

RESULTS

OptiBond All-In-One adhesive showed significantly higher mean SBS values on both types of tooth structures (enamel and dentin) and under different conditions (control and thermocycled) compared with the other three adhesives ( < 0.001), except in the enamel-thermocycled group, where the Single Bond Universal adhesive showed higher mean SBS but without a significant difference compared with the OptiBond All-In-One adhesive ( = 0.266), and there was no significant difference between OptiBond All-In-One and G-aenial Bond in the same group ( = 0.192). Conversely, Bond-1 SF showed significantly lower mean SBS values compared with those of the other three adhesives on different types of tooth structures and under different conditions (control and thermocycled) ( < 0.001).

CONCLUSION

One-step self-etch adhesives containing ethanol as a solvent or co-solvent showed higher SBS compared with the other self-etching bonding agents. The bond strength values of these adhesives to dentin are significantly higher than those to enamel.

CLINICAL RELEVANCE

The types of solvents of one-step self-etch adhesives had an effect on SBS, and the absence of solvent in those adhesives would adversely influence their performance. How to cite this article: Ageel FA, Alqahtani MQ. Effects of the Contents of Various Solvents in One-step Self-etch Adhesives on Shear Bond Strengths to Enamel and Dentin. J Contemp Dent Pract 2019;20(11):1260-1268.