Effect of adhesive coating on calcium, phosphate, and fluoride release from experimental and commercial remineralizing dental restorative materials

Abstract

This study investigated the potential of adhesive coating for hindering the reactivity of ion-releasing dental restorative materials. Experimental composites were prepared by replacing 10 or 20 wt% of reinforcing fillers with two types of bioactive glass. A glass ionomer, a giomer, and an alkasite were used as representatives of commercial ion-releasing materials. Restorative material specimens were coated with an etch-and-rinse adhesive, 1-step self-etch adhesive, 2-step self-etch adhesive, or left uncoated. The specimens were immersed in a lactic acid solution and ion concentrations were measured in 4 days intervals for 32 days (atomic absorption spectrometry for calcium, UV–Vis spectrometry for phosphate, ion-selective electrode for fluoride, and pH-meter for pH values). The adhesive coating reduced ion release between 0.3 and 307 times, in a significantly material- and adhesive-dependent manner. Fluoride release was most highly impaired, with the reduction of up to 307 times, followed by phosphate and calcium release, which were reduced up to 90 and 45 times, respectively. The effect of different adhesive systems was most pronounced for phosphate release, with the following rankings: uncoated ≥ 2-step self-etch adhesive ≥ 1-step self-etch adhesive ≥ etch-and-rinse adhesive. The differences among adhesives were less pronounced for calcium and fluoride. It was concluded that the resinous adhesive layer can act as a barrier for ion release and diminish the beneficial effects of remineralizing restorative materials.

The Fluoride Ion Release from Ion-Releasing Dental Materials after Surface Loading by Topical Treatment with Sodium Fluoride Gel

“…Similar considerations were also expressed in the study by Wang et al [ 29 ] in which they investigated the effects of the coating on initial fluoride release from resin-modified glass-ionomer cements [ 29 ]. Another study by Par et al [ 30 ] came to similar conclusions by demonstrating that fluoride release from coated specimens of the alkasite composite (Cention) was reduced 300-fold compared to the uncoated specimens [ 30 ]. In contrast to these results, Tay et al [ 31 ] suggested that adhesives may act as permeable membranes that allow remineralization of tooth structure and arrest the caries process.…”

Water-Induced Changes in Experimental Resin Composites Functionalized with Conventional (45S5) and Customized Bioactive Glass

“…When the same resin system was functionalized with 10 wt% of three different BG compositions, even higher water sorption was measured (107.4–132.7 μg/cm 3 ). Such a highly hydrophilic resin system was not required for experimental composites in our study because the hydrophilicity of the unsilanized BG particles themselves allowed sufficient water diffusion, as demonstrated in previous in vitro studies of the same experimental composites regarding ion release [ 21 , 42 ] and protective effects on dental hard tissues [ 22 , 23 ].…”

“…For the experimental composites that tended to form a thick resin-rich layer (F-10 and F-40), these procedures would also improve calcium phosphate precipitation by exposing BG particles. In any case, the different thicknesses of the resin-rich layer observed in the experimental composites deserve further investigation, as this layer may influence the caries-preventive effect by isolating reactive fillers from the aqueous environment and reducing their dissolution, as well as the release of remineralizing ions [ 42 ].…”

Bioactivity and remineralization potential of modified glass ionomer cement: A systematic review of the impact of calcium and phosphate ion release

“…Two studies in this systematic review investigated Ca, P and F release using atomic absorption spectrometry (for Ca), ultraviolet-visible (UV-Vis) spectroscopy (for P), and ion-selective electrode analysis (for F) 47,48) . Par et al reported that the resinous adhesive layer could act as a barrier for ion release, significantly reducing the remineralization properties of restorative materials.…”