Analysis of the interaction of self-etching and universal adhesives containing functional resin monomers to sound, irradiated and artificially eroded human dentin

Abstract

With the mastery of knowledge about caries-related dysbiosis and changing habits, other clinical conditions of altered dentin have been standing out and featuring new challenges in terms of preventive and therapeutic approaches. Specific clinical events such as radiation caries and cases in which tooth wear occurs, modulated by erosion, are becoming more frequent. The resulting dental substrates have particular characteristics that must be better understood to offer more effective approaches.These conditions hamper bonding procedures, since such dentinal alterations provide a substrate softened by superficial mineral loss and altered molecular arrangement. Clinical situations as in radiation caries, or a superficially demineralized surface followed by hypermineralization in more advanced stages (deposition of sclerotic dentin), as in erosion, are remarkable substrates that require more attention to allow better interaction with the materials.From this perspective, the development of self-etching and universal systems containing functional monomers, in particular 10-MDP (10-methacryloyloxidecyl dihydrogen phosphate) introduced a very promising new class of adhesives due to its ability to associate micromechanical to chemical interaction with the tooth structure. Such properties improve bonding conditions, meanwhile, they provide a reduction in clinical time, less technical sensitivity and less postoperative sensitivity.Since then, other systems containing different types of functional monomers have been introduced into the market. One of these systems are the bonding systems based on a mixture of carboxylic and phosphonic acids. Additionally, components considered bioactive based on Giomer technology, which have in their composition pre-reacted glass particles pre-treated with polyacrylic acid (S-PRG) have been launched. These systems contain a multi-ionic technology and feature a functional monomer that, according to the manufacturer, also interacts with the collagen fibrils of the tooth structure. These properties, however, lack scientific evidence, especially in understanding their mechanism. The aim of this study is to evaluate the interaction of the main self-etching and universal adhesives based on different functional monomers available on the market, regarding their properties related to adhesion, when applied to sound human dentin, irradiated carious and artificially eroded dentin. The adhesive systems investigated will be: Clearfil SE Bond, Adper Single Bond Universal, FL Bond II, Beautibond Xtreme and Adper Scotchbond Multipurpose. The dentin bonging systems will be evaluated regarding bond strength to dentin (BS) by microtensile for 6 months, complemented with fracture analysis of the interface by optical microscopy (40x) and by SEM and degree of conversion (GC) through infrared spectroscopy with transform of Fourier (FTIR).The results of the tests will be submitted to the analysis of normality and homogeneity of the data. If possible, they will be submitted to the ANOVA test and the Tukey test with a significance level of 5%.