Resin-dentin interfacial morphology and shear bond strengths to primary dentin after long-term water storage: An in vitro study

Objective: To evaluate the resin-dentin interfacial morphology and shear bond strength of several new dentin bonding systems on deep dentin of primary teeth after a 1-year storage period. Method and Materials: Test specimens were prepared using 5 adhesive systems (Syntac Single-Component [Ivoclar Vivadent], Prime & Bond NT [Dentsply DeTrey], Adper Prompt L-Pop [3M ESPE], Gluma One Bond [Heraeus Kulzer], and iBond [Heraeus Kulzer]) on primary deep dentin. The shear bond strength data were evaluated with Kruskal-Wallis and Mann-Whitney U tests. Debonding surfaces were examined with stereomicroscope and scanning electron microscopy (SEM). Results: The 1-day shear bond strength test values were, respectively, Adper Prompt L-Pop > iBond > Prime & Bond NT > Gluma One Bond > Syntac Single-Component, with the differences between Prompt LPop and Syntac (U = 10, P = .006), Prompt L-Pop and Gluma (U = 7, P = .002), and Adper Prompt L-Pop and iBond (U = 16, P = .03) being statistically significant. The 365-day shear bond strength values were, respectively, Adper Prompt L-Pop > Prime & Bond NT > iBond > Syntac Single-Component > Gluma One Bond, with the differences between Adper Prompt L-Pop and Syntac (U = 0, P = .000), Adper Prompt L-Pop and Gluma (U = 1, P = .000), and Adper Prompt L-Pop and iBond (U = 13, P = .01) being statistically significant. The differences between the 1-day and 365-day subgroup values of Syntac (U = 18; P = .05) and Gluma (U = 1, P = .000) were statistically significant. Almost all specimens showed adhesive failure at stereoptical examination (P > .05), with the presence of resin remnants and tags on dentin and dentinlike remnants on resin surfaces at SEM. Conclusion: Syntac and Gluma group values decreased with aging. The best values were obtained with both Adper Prompt L-Pop groups. Keywords: adhesive resin, primary dentin, shear bond strength, storage