In vitro analysis of dentin remineralization using an experimental composite containing calcium silicate particles

Abstract

Calcium silicate-based cements have proven to be an efficient therapy in the context of minimally invasive restorative dentistry. Although they are promising in the dentin remineralization process, there are limitations regarding their indication as a restorative material due to their low mechanical resistance. The objective of the present study is to evaluate the remineralizing potential of an experimental resinous composite containing calcium silicate, in comparison to commercially available bioactive restorative materials. Calcium silicate particles (MTA Angelus, Londrina, Brazil) will be characterized in terms of size distribution (laser light scattering) and morphology, using scanning electron microscopy (SEM). The particles will be added in a fraction corresponding to 30vol% to a resin matrix with an equimolar ratio of BISGMA and TEGDMA. The bioactive composites TheraCal LC (Bisco, Schaumburg, USA), Beautifil II (Shofu, Kyoto, Japan) and Cention N (Ivoclar Vivadent, Schaan, Liechtenstein) will be evaluated. As a control, a commercial composite will be used (Filtek Z250; 3M ESPE, St Paul, USA), and the materials will be evaluated after 24 hours regarding the degree of conversion (FTIR spectroscopy, n=5), fracture resistance and flexural modulus (test biaxial bending, n=10). The fractured surfaces of the specimens will be observed in SEM. After 28 days of immersion in deionized water, the alkalinization capacity of the medium (n=3) and the release of calcium ions will be analyzed using optical emission spectroscopy with inductively coupled plasma and that of fluoride using an ion-specific electrode (n =3). Discs of partially demineralized dentin will be evaluated after 28 days of immersion in simulated body fluid in contact with the materials. The mineral:matrix ratio (RMM) of the dentin at the interface with the material will be determined by ATR-FTIR spectroscopy. Dentin hardness and modulus of elasticity will be obtained using an ultramicrohardness meter. The dentin surface in contact with the materials will be observed in SEM with an energy dispersive detector (EDS). Data will be analyzed using ANOVA/Tukey test (alpha: 0.05). (AU)