Thermocycling showed no significant effects on the bond strength of 3-step etch and rinse system to caries-affected dentin, although there were significant reductions in bond strength to sound dentin. Moreover, for 1-step and 2-step self-etch adhesives, no significant effect on bond strength was detected when bonded to sound and caries-affected dentin [46]. Fluid penetration into the resin–dentin interface occurs via dentinal tubules under constant hydrostatic pulpal pressure, as well as via the dentin margin. Therefore, the presence of mineral LGK-974 datasheet deposits in dentinal tubules may alter the bonding durability between normal and caries-affected dentin. Nakajima et al. [47] reported that constant

hydrostatic pulpal pressure during 1-month storage significantly decreased the bond strength of 2-step self-etch system to normal dentin, but did not affect the bond strength to caries-affected dentin. The lower dentin permeability of caries-affected dentin may therefore reduce water penetration into the interface, leading to long-term stability of the interface when there is no direct exposure to water in presence of the surrounding bonded enamel. Tubular occlusion may prevent water entrapment,

this website being manifestations of evaporative and convective water flux from dentin, at the resin–dentin interface [49]. Current one-step self-etch adhesives show higher hydrophilicity, and attract water from the hydrated dentin substrate during application on the adhesive surface and absorb water even after polymerization. Ultrastructurally, water entrapment in the 1-step self-etch adhesive layer is observed in the bonded normal dentin specimen as water-filled channels (i.e. water-tree, water-droplet), however water-treeing and water-droplet formation can be eliminated in the bonded caries-affected dentin specimen [49]. In the absent of water fluxes from caries-affected dentin, a one-step self-etch adhesives might initially establish a better seal along the interface. Cobimetinib supplier However, the absorbed water in the adhesive

layer would cause hydrolytic degradation of resinous materials over time, compromising the integrity of the resin–dentin interface. Some researchers have evaluated the effect of caries removal method on bonding to caries-affected dentin [50] and [51]. Using etch and rinse system of Single Bond (3M), caries removal methods (steel bur in a slow-speed handpiece, air abrasion with aluminum oxide particle, partially diamond-coated oscillating tip with airscaler, hand excavator with Carisolv) did not affect the bond strength to caries-affected dentin [50]. This result is in agreement with another study using etch and rinse system of OptiBond Solo Plus Total-Etch (Kerr), in which there were no significant differences in bond strength to caries-affected dentin between excavation by a steel round bur in a slow-speed handpiece, Er:YAG laser and 600-grit SiC paper [51].