Objectives: The aim of this in vitro study was to evaluate the micro shear bond strength of different adhesive system strategies to sound, artificially caries affected and remineralized dentin substrates.
Materials and Methods: Sixty bovine permanent incisors were used. The labial enamel was removed and a flat dentin surface was obtained. The dentin specimens were divided into three main groups (sound as a control, artificial caries affected and remineralized dentin groups). Four adhesive systems were applied over the different dentin substrates according to the directions of the manufacturers; (Futurabond M+, Single bond universal (universal adhesives used in self-etch mode, Futurabond DC (Dual- curing self etch bond with nanofillers and Solobond M (Etch and rinse adhesive). After preparation of the 240 micro tubules of resin composite (Filtek TM Z350XT (Flow able restorative), micro shear bond strength test was performed. The results were tabulated and statistically analyzed. Failure mode was detected for all the fractured dentin specimens using the stereomicroscope. ESEM evaluation was done for resin dentin interfaces for all types of adhesives.
Results: There was a statistically significant effect of dentin substrate, while the adhesive system type was not. One way ANOVA followed by Tukey HSD post hoc test showed that, the remineralized dentin recorded the highest micro shear bond strength value with Single Bond Universal followed by Futurabond M+. The artificial caries affected dentin showed the highest micro shear bond strength value with Solobond M followed by Futurabond DC, which also recorded the lowest micro shear bond strength result with remineralized dentin.
Conclusions: 1- Performance of the tested adhesives strategies was shown to be dentin-dependant.2- Dentin pretreatment with CPP-ACPF containing paste affects positively the micro-shear bond strength of Single bond universal and Futurabond M+ universal adhesives when used in self-etch mode.3-The specific chemical formula of the tested resin adhesives might coordinate with the demineralized dentin.