Efficacy and micro-characterization of pathophysiological events on caries-affected dentin treated with glass-ionomer cements

Abstract

The aim of this study was to evaluate if mechanical cycling influences bioactivity and bond strength at the glass-ionomer cement-dentin interface, after load cycling.Microtensile bond strength (MTBS) was assessed with Ketac-Bond (conventional glass ionomer/GIC) or Vitrebond Plus (resin-modified/RMGIC), in sound dentin or in cariesaffected dentin (CAD). Debonded dentin surfaces were studied by field emission scanning electron microscopy (FESEM), and remineralization was evaluated through nanohardness (Hi) and Young's modulus (Ei), Raman spectroscopy, and Masson's trichrome staining technique. Load cycling did not affect MTBS, except when KetacBond was applied on sound dentin, which attained 100% pretesting failures. Minerals precipitated in porous platforms. GIC promoted total occlusion of tubules, and RMGIC originated empty or partial occluded tubules. In sound dentin, load cycling produced an increase of the relative presence of crystalline minerals after using Ketac-Bond The null hypothesis to be tested is that bond strength, chemical bonding and mechanical performance of the tested ionomer-based cements would not be influenced by the application of load cycling on restorations of sound and caries-affected dentin substrates.

Remineralizing Ability of Resin Modified Glass Ionomers (RMGICs): A Systematic Review

“…Overall, the comparison between GICs and modified RMGICs has shown no significant differences, with small variations depending on the studies [ 34 ]. This result is of particular interest since, in studies assessing only fluoride release, it was concluded that the RMGICs had less remineralizing power.…”

In vitro mechanical stimulation facilitates stress dissipation and sealing ability at the conventional glass ionomer cement-dentin interface

“…Formation of a shallow hybrid layers (HL) (~1-2 µm depth) made of cement and collagen [2,3] definitely contribute to micro and nano-mechanical bonding [4,5]. A volume of demineralized/unprotected collagen remains at the bottom of the hybrid layer (BHL) [6]. This vulnerable unsupported collagen may become the sites for collagen hydrolysis by host-derived matrix metalloproteinases (MMPs) enzymes [7] or by other proteases from bacteria [8] that may trigger the interface degradation [3].…”

“…Resin-modified glass-ionomer cements (RMGIC) set, when mixed, through an acid-base reaction between ion-leachable glasses and polyalkenoic acids, as well as upon light-polymerization of water-soluble (metha)crylate, such as HEMA [9]. Phosphate and calcium and lower fractions of aluminum, sodium or strontium have been previously measured at the cement-dentin interface [6]. They become integrated in this porous, nonparticulate, poly(HEMA)-rich hydrogel layer [10], the absorption layer [11].…”