Analysis of physical-chemical interaction of normal, irradiated and artificially eroded human dentin with functional resin monomers

Abstract

Taking the characteristics of dentin and the main clinical conditions that alter it into account was certainly essential for the promissory improvement on dentin bonding systems use into the different preventive/therapeutic approaches. Despite caries disease, more particular clinical events as irradiated caries and dental wear as erosive tooth wear have been notably prevalent, which in this case is also attributed as a behavior disease. These conditions result in clinical challenges as they present either smoother surfaces due to loss of superficial minerals or situations with more hypermineralized dentin resulting from the deposition of sclerotic dentin reaction, which determine two distinct scenarios to establish the bonding process, as the base of the majority of restorative procedures for these cases.In this context, since its introduction, self-etching dentin bonding systems (DBSs), mainly based on 10-MDP (10-methacryloyloxydecyl dihydrogenphosphate), has been strongly auspicious, especially due to their chemical binding potential conciliated with its interesting technical features and pos operatory sensitive reduction. The reduced technical sensitivity and chemical potential also can drive to more favorable conditions to treat substrates with diversity of characteristics.Simultaneously to new monomers developing, the knowledge of biological perspectives of bonding process evidenced the role of dentin intrinsic proteolytic enzymes, as metaloproteinases of dentin matrix (MMPs) and Cystein Cathepsins (CCs) on the degradation of collagen fibrils, specially in demineralization conditions as dental caries and erosion. In this way, the use of proteolytic inhibitors, mainly chlorhexidine (CHX) has been widely investigated and employed. However, the association of CHX with MDP-based DBSs is not totally elucidated and sounds to negatively affect some properties as bonding to dentin. This performance is controversial to positive evidences when MDP-free DBS are used combined to CHX. Since the launch of multimode dentin bonding systems, this association is clinically applicable. Others self-etching systems based on other functional monomers also can perform specifically. One of these systems is giomer-based, with the presence of pre-reacted glass surface and phosphonic acid monomer. Thus, investigate the effect of this interaction seems to be relevant to avoid the benefits provided by two strategies, which can become antagonistic. The main of this study is to evaluate the interaction between functional monomers and chlorhexidine and its implication on properties related to the bonding on sound, simulated irradiated carious and artificial eroded dentin. Using digluconate of chlrohexidine in two concentrations of CHX (0% and 2%), they will becombined with different DBSs: Clearfil SE Bond, Clearfil Protect Bond, Adper Single Bond Universal, FL Bond II, Beautibond and Adper Scotchbond Multipurpose, representing the main DBSs categories to determine molecular profile of main elements and molecular arrangements, bond strength (BS) to dentin up 12 months, degree of conversion (DC) through Fourier Transform Infrared (FTIR) and wettability trough the analysis of contact angle using a goniometer. Data of tested properties will be submitted to analysis of normal distribution and homogeneity. If possible, they will be assessed using ANOVA and Tukey tests with significant level of 5%. (AU)