The aim of this in vitro study was to evaluate the ability of the new strontium-containing composite, Stela (SDI, Victoria, Australia), to induce hydroxyapatite formation and promote remineralization of demineralized dentin, compared to SDR Flow+ (York, PA, USA). Twenty-four dentin slices (1 mm thick) were obtained from extracted wisdom teeth using a microtome and demineralized with 17% EDTA for 2 h. A layer of either Stela or SDR Flow+ was applied to each slice, allowed to set, and preserved in 0.1% thymol solution. Samples were analyzed at 1, 7, 14 and 28 days (n = 3 per group and time). Measurements were taken at baseline, after demineralization, and after application. Apatite formation was assessed using Fourier-transform infrared spectroscopy (FTIR), while changes in the Calcium/Phosphate (Ca/P) ratio were evaluated by Energy Dispersive Spectroscopy (EDX). Statistical comparisons were performed using the Wilcoxon test (p < 0.05). Both materials promoted carbonated hydroxyapatite formation and increases in calcium and phosphate. Stela exhibited an apatite peak (1420 cm⁻¹) as early as 24 h and significant increases in calcium and phosphate from day 7. SDR Flow+ reached its peak at 14 days and showed significant increases in the Ca/P ratio. By 28 days, both materials achieved comparable remineralization, confirming their effectiveness in treating demineralized dentine.

Dental caries disrupt the balance between demineralization and remineralization in dentin, a complex mineralized tissue whose recovery requires not only mineral redeposition but also reconstitution of the collagen-apatite hierarchical organization. Restoring this integrity within a minimally invasive restorative framework demands materials that actively participate in tissue recovery, beyond passive cavity sealing. This systematic review aimed to synthesize the available evidence on experimental resin-based composites with remineralizing capacity, evaluating their bioactive filler composition, ion-release efficacy, and mechanical properties. A systematic search was conducted in MEDLINE, Scopus, Embase, Web of Science, and SciELO following PRISMA guidelines, yielding 12 in vitro studies after screening. Three main remineralizing strategies were identified: amorphous calcium phosphate nanoparticles (NACPs), alone or combined with the non-collagenous protein analog PAMAM; bioactive glass fillers (particularly 45S5); and other calcium phosphate-, calcium silicate-, or multi-ion-releasing fillers (β-TCS, DCPD and S-PRG). Scanning electron microscopy was the most frequently used evaluation method, often complemented by EDS, FTIR, and mechanical testing. Methodological quality was mostly moderate, with widespread absence of sample size justification and blinding. These in vitro findings provide proof of concept for the remineralizing potential of bioactive resin composites, although their clinical efficacy, long-term durability, and safety remain to be validated, and greater methodological standardization is needed.