Effect of whitening toothpastes on bonding of restorative materials to enamel of primary teeth

Objective: The aim of this in vitro investigation was to measure shear bond strength (SBS) of a resin composite and a resin‑modified glass ionomer to enamel of primary teeth after application of different whitening toothpastes (WTs).Materials and Methods: Eighty labial enamel surfaces of primary incisors were randomly distributed into 8 groups of 10 each according to the surface treatment and bonding material. G1 and G2, control (brushed with water without WT); G3 and G4, (brushed with Colgate Optic White WT [Colgate‑Palmolive Company, New York, NY, USA]), G5 and G6, (brushed with Crest Pro‑Health Whitening WT [Procter and Gamble, Cincinnati, OH, USA]) and G7 and G8, (brushed with Arm and Hammer Advance White Extreme Whitening with Stain Defense WT [Church and Dwight Co., Princeton, NJ, USA]). SBS was measured at a crosshead speed of 0.5 mm/min and the type of bond failure was assessed using a stereomicroscope.Results: There was significant difference between SBS of composite resin in groups 1, 3, 5, and 7 (P < 0.001), but no difference between resin‑modified glass ionomer in groups 2, 4, 6, and 8 (P < 0.056). SBS of group 1 (control) was greater than groups 3, 5, and 7. There was a significant difference between group 1 and group 2 as well as group 7 and group 8 (P < 0.001).Conclusions: WTs affect SBS of resin composite, but not resin‑modified glass ionomer to enamel of primary teeth. No difference of failure modes between different groups of tested materials.Key words: Dental enamel, restorative materials, shear bond strength, whitening toothpast