Ions-modified nanoparticles affect functional remineralization and energy dissipation through the resin-dentin interface

Abstract

The aim of this study was to evaluate changes in the mechanical and chemical behavior, and bonding ability at dentin interfaces infiltrated with polymeric nanoparticles (NPs) prior to resin application. Dentin surfaces were treated with 37% phosphoric acid followed by application of an ethanol suspension of NPs, Zn-NPs or Ca-NPs followed by the application of an adhesive, Single Bond (SB). Bonded interfaces were stored for 24 h, submitted to microtensile bond strength test, and evaluated by scanning electron microscopy. After 24 h and 21 d of storage, the whole resin-dentin interface adhesive was evaluated using a Nano-DMA. Complex modulus, storage modulus and tan delta (δ) were assessed. AFM imaging and Raman analysis were performed. Bond strength was not affected by NPs infiltration. After 21 d of storage, tan δ generally decreased at Zn-NPs/resin-dentin interface, and augmented when Ca-NPs or non-doped NPs were used. When both Zn-NPs and Ca-NPs were employed, the storage modulus and complex modulus decreased, though both moduli increased at the adhesive and at peritubular dentin after Zn-NPs infiltration. The phosphate and the carbonate peaks, and carbonate substitution, augmented more at interfaces promoted with Ca-NPs than with Zn-NPs after 21 d of storage, but crystallinity did not differ at created interfaces with both ions-doped NPs. Crosslinking of collagen and the secondary structure of collagen improved with Zn-NPs resin-dentin infiltration. Ca-NPs-resin dentin infiltration produced a favorable dissipation of energy with minimal stress concentration trough the crystalline remineralized resin-dentin interface, causing minor damage at this structure.

Zinc Inhibits Collagenolysis by Cathepsin K and Matrix Metalloproteinases in Demineralized Dentin Matrix

“…Zinc, being a structural component of many proteins, can enhance the thermo-mechanical stability of peptides by binding to specific sites [Sakharov and Lim, 2005;Jiang et al, 2009;Toledano et al, 2017]. According to the dry mass loss results in the present study, zinc levels of ≤ 1 m M were insufficient to prevent DOM degradation since the mass loss of specimens containing 0-1 m M Zn 2+ were similar to the controls.…”

The interrelationship of microstructure and hardness of human coronal dentin using reference point indentation technique and micro-Raman spectroscopy

“…The mineral-organic matrix ratios (960/1452 and 960/1667cm −1 ) were calculated by integrating the area under the peaks to analyze differences in the chemical composition in SD and DD [17]. The phosphate/carbonate ratio was obtained similarly to analyze differences in the mineral composition at SD and DD [18]. To assess any differences in degree of the crystallinity at SD and DD, the full-width at half maximum (FWHM) of phosphate peak at 960cm −1 was measured [16].…”

Silver improves collagen structure and stability at demineralized dentin: A dynamic-mechanical and Raman analysis

“…From this test, nanohardness (Hi) and nanoindentation modulus (Ei) of the samples, were obtained. The rest of the procedures were as in Oliver and Pharr, 1992 [22] and Toledano et al, 2017 [23]. Data were analyzed by two-way ANOVA (independent factors were NPs application and storage time) and Student-Newman-Keuls multiple comparisons (P < 0.05).…”

“…Clusters were created following Ward´s technique and the dendrogram was calculated applying three factor spectra or principal components, corresponding with three different components at the dentin surface (red, blue and green). At this point, the mineral (relative presence of minerals and crystallinity) and organic components (normalization, crosslinking, nature and secondary structure of collagen) of dentin was assessed as previously published [23,24].…”