Effect of Povidone-Iodine and Hydrogen-Peroxide Mouthwashes on Shear Bond Strenth to Enamel

Abstract

Aim: During COVID-19 pandemic, use of different mouthwashes have been recomended toreduce the viral load. Aim of this study is to compare the effect of different mouthwashes onshear bond strength of a universal adhesive in regard to self-etch (SE) and etch and rinse (ER)application modes.Materials and Methods: 100 sound human maxillary central incisors were selected. Flat enamelsurfaces were obtained. Specimens were randomly assigned to 5 groups (n=20) [Control, 1.5%hydrogen-peroxide(H2O2), 0.2% povidone-iodine (PVP-I), Listerine, Chlorhexidine (CHX)]. Then,each group was divided into two subgroups according the application mode of the useduniversal adhesive (Single Bond Universal) (n =10). After adhesive procedures, resin compositewas applied by a Teflon mold (2mm height, 2.4mm diameter) and light polymerized. Shear bondstrength was tested with a Universal testing machine after water storage for 24 h. The debondedareas were examined for failure mode analysis with a stereomicroscope at 25×magnifications.The data were statistically analyzed by two-way ANOVA and Bonferroni test (p<0.05).Results: Etch and rinse application mode of the adhesive system led to higher shear bond strengthsthan self-etch application mode, regardless of the preoperational antiseptic mouthwashes used(p<0.001). The lowest shear bond strength values among all the tested groups were measuredfor H2O2/SE group (3.77±1.37MPa). The control group (where no mouthwash was used) exhibitedthe highest SBS values (26.43±4.35MPa) in SE mode (PVP-I/SE=8.70±1.92, Listerine/SE=9.99±2.90;CHX/SE=17.67±4.37MPa) (p<0.05). PVP-I/ER group (24.04±5.01MPa) showed no significantdifference with H2O2, CHX, Listerine and control groups in ER mode (21.40±3.67, 28.30±6.03,29.61±4.78, 31.48±7.45) (p>0.05). H2O2 presented lower shear bond strength (21.40±3.67MPa) thanother mouthwashes in ER mode (p<0.05). The adhesive failure mode was predominant for allgroups.Conclusion: The antiseptic mouthwashes decreased the enamel bond strength of the universaladhesive used in self-etch application mode, however only H2O2 reduced the enamel bondstrength in both application modes.Keywords: hydrogen peroxide, mouthwash, povidone iodine, shear bond strength, chlorhexidine