How 10-MDP functional phosphate monomer and 2% digluconate chlorhexidine solution interact on sound, artificial carious or eroded dentin substrates

Abstract

How 10-MDP functional phosphate monomer and 2% digluconate chlorhexidine solution interact on sound, artificial carious or eroded dentin substrates Objective: Carious and eroded dentin represent common modified dental substrates, which mostly require restorative procedures. MDP-based dentin bonding system (DBS) and digluconate chlorhexidine (CHX) are presented as promising agents to minimize intrinsic degradation of the resin-dentin interface by interaction with calcium (Ca). Therefore, the purpose of this study was to explore the possible interaction between MDP in a universal adhesive system with 10-MDP in self-etching mode and CHX on substrates artificially modified by caries and erosion, through microtensile bond strength (µTBS). Additional characterization of the adhesive interface was performed by SEM/EDS analyses. Material and methods: Flat dentin surfaces were obtained from 120 specimens (n=20/group) prepared from extracted sound human third molars and randomly divided into three groups according to the dentin substrate: sound-control (S), artificial carious (C) and artificial eroded (E). Half of these specimens were pretreated with distilled water (W) and other half with 2% CHX, constituting 6 groups: S-W, S-CHX, C-W, C-CHX, E-W, E-CHX. After, all the specimens were restored with a universal adhesive system (Apder Single Bond Universal) using self-etching mode and two increments of composite resin (Filtek Z-350), following manufacturer's instructions. Slices (0.8mm) were obtained to SEM analysis and beams (0.64mm²) were obtained and evaluated by EDS analysis and µTBS in universal testing machine (500N/ 0.5mm/min) after 24 hours and 6 months. Data was statistically analyzed by two-way ANOVA and Tukey tests (p<0.05). Results: Substrate type was a statistically significant factor (p<0.0001), whereas the pretreatment (p=0.189), time (p=0.337) and the interaction between three factors (p=0.452) were not significant. Conclusion: Carious and eroded dentin substrates negatively interfered on the bond strength of an MDP-based universal adhesive systems, regardless its use with CHX. Likely, the reduction of available calcium from these substrates impaired the effectiveness of this system.

Influence of Diabetes Mellitus and Universal Adhesive Application Mode on the Bond Strength of Composite Resin to Dentine

“…Dentin has a reduced mineral content compared to enamel,which decreases after etching using phosphoric acid. This may be one of the reasons for the poor chemical bond of the 10-MDP monomers ( 37 ). In addition, phosphoric acid is applied as an additional step prior to adhesive application, which can demineralize dentin 3-6 micrometers deeper than the penetration depth expected with self-etch adhesives resins.…”