Effects of Disinfection Treatments on Bond Strength of Self-etch Adhesives

Objectives: In daily dental practice, several methods are used for cavity disinfection. The aim of this study was to evaluate the effect of two different disinfection treatments on shear bond strength (SBS) of self-etch adhesives to coronal and root dentin.

Materials and Methods: Sixty extracted human canines were ground flat exposing the coronal and root dentin surfaces, and randomly divided into 3 groups. The surface was untreated as the control (G1), or treated with Ozone (HealOzone/KaVo) (G2) or 1.5 W, 15 Hz Nd:YAG laser (Fidelis III/Fotona) for 30 seconds (G3). Then, coronal and root dentins of 10 teeth for each group were treated with a one-step self-etch adhesive Clearfil Tri-S Bond (Kuraray; S3), while the remaining 10 teeth were treated with a two-step self-etch adhesive Clearfil SE Bond (Kuraray; SE). A nano-composite (Majesty Esthetics, Kuraray) was applied, and SBS was tested by a universal testing machine (1 mm/minute) using a special jig (Ultradent). Failure modes were determined under a stereomicroscope. The mean SBS values of each group were calculated and data were subjected to statistical analysis (p=0.05).

Results: On root dentin, although G2/SE showed statistically higher values than G3/S3, the differences within other groups were not significant (p>0.05, ANOVA followed by Tukey HSD). On coronal dentin, application of SE to G1 resulted in higher values than G1/S3, G2/S3 and G3/S3 (Welch ANOVA followed by Dunnet T3). Comparisons of two dentin substrates in each group didn't show any significant difference except for G1/SE, in which coronal dentin showed higher SBS (Paired samples t-test). The failure modes of all groups were mainly adhesive.

Conclusion: Disinfection treatments with Nd:YAG laser and Ozone didn't impair the SBS of both of the self-etch adhesives used to coronal and root dentin.