In the results, the outer lesion, which is the dentin surface demineralized to simulate caries dentin lesion, was observed in both intact and caries-affected dentin. The depth of the outer lesion Estrogen antagonist ranged from 10 μm to 15 μm, in which there was no

difference between intact and caries-affected dentin. The adhesive demonstrated a good resistance to the acid–base challenge in the intact and caries-affected dentin specimens. The hybrid layer detected after argon-ion etching (H) was approximately 1 μm thick for the intact dentin, while a slightly thicker hybrid layer (H) was observed for the caries-affected dentin. These measurements were similar to the previous studies [22] and [23]. In addition, an ABRZ was observed beneath the hybrid layer (H) in SEM micrographs of both the intact and caries-affected dentin specimens. An ABRZ, approximately 1 μm thick, was observed beneath the hybrid layer (H) for the intact dentin, while a thicker ABRZ, approximately 1.5 μm thick, was created in the caries-affected dentin. The mechanism of action for this two-step self-etching primer adhesive involves dissolution

of the smear layer and demineralization of the underlying dentin by an acidic monomer, namely 10-methacryloxydecyl dihydrogenphosphate (MDP) in the primer, resulting in mild surface etching. Formation of an ABRZ by Clearfil SE Bond would be related to the Gemcitabine ic50 penetration of the adhesive, but also to the quality of the hybrid layer (H). Since the caries-affected intertubular dentin is already partially demineralized and more Selleckchem Dactolisib porous, caries-affected dentin is softer than normal dentin [24] and [25]. Thus, the intertubular dentin in caries-affected dentin should be more permeable to the primer than in normal dentin. Moreover, the smear layer of caries-affected dentin might

be more porous than that of normal dentin [21]. Therefore, it was suggested that resin monomer could penetrate deeper into caries-affected dentin than intact dentin, resulting in a thicker hybrid layer (H) in caries-affected dentin. In the mentioned study, the ABRZ and the surrounding lesion were also characterized by the nanoindentation technique. The mean values of the nanoindentation test (Fig. 3) demonstrated differences in the microhardness between the intact and caries-affected dentin specimens. As expected, microhardness of the intact dentin area was significantly higher than that of the caries-affected dentin [26]. Interestingly, the area 2 μm beneath the hybrid layer (H) in caries-affected dentin indicated a significantly higher microhardness compared to other dentin areas. This zone was coinciding with the ABRZ in the SEM observation (Fig. 2). Dentin microhardness around the hybrid layer (H) was approximately 35 mgf/μm2 for both the intact and caries-affected groups.