Developing materials capable of inducing specific biomineralization is a desirable goal [1]. Numerous conditions requiring biomineralization encourage the progress of this field, but the controlled formation of hydroxyapatite nanocrystals in calcified tissues still needs to be developed [2], [3].

The bioactivity of materials depends on their ability to release substantial amounts of ions [4]. It is fundamental for material-induced biomineralizing tissue to a high free energy level and to release calcium and phosphate ions in a specific ratio to promote crystal nucleation and growth [4], [5]. Biomineralization is therefore associated with the composition and microstructure of materials and local tissue environmental conditions. Proposed bioactive materials in dentistry range from the broadly used mineral trioxide aggregate (MTA) to more recently developed ready-to-use calcium silicate-based materials (CSMs) with a wide variety of components and technical features. Nevertheless, most available products only represent sources of calcium ions and rely on phosphate-containing physiologic fluids from the environment for apatite formation, which may be lower than required for mineral formation [6]. In addition, the free energy provided is usually insufficient to produce hydroxyapatite, but amorphous crystal phases are generally formed and poorly attached to tissues [7]. In this sense, a calcium phosphate-based composition for CSMs optimizes the biomineralization reaction because it provides mineral configurations that precede the biological formation of apatites [7]. The β-tricalcium phosphate (BTCP) is a polymorph phase of tricalcium phosphate commonly added in biomaterials because it presents higher solubility and faster resorption kinetics than other apatite minerals [8], [9]. Therefore, the energy required to achieve these initial apatite configurations is saved and can be used to form products more stoichiometrically, crystallographically, and thermodynamically like natural hydroxyapatite [5], [7].

Current biomaterials synthesis emphasizes the nanoscale control of tissue formation at the molecular scale [10]. It is essential for proper biomimetic intrafibrillar collagen mineralization with hydroxyapatite crystals of nanometer sizes (∼3–10 nm), ensuring tissue recovery with optimal strength and maximum tolerance to a flaw [5], [11]. As a result, silicate-based bioactive glass nanoparticles are gaining increasing attention because of their association with favorable material-induced biomineralization with improved dissolution kinetics [12], [13], [14], [15]. However, the knowledge of silicate-based bioactive glass nanoparticles and their application in several areas, such as dentistry, remains to be explored [13], [16].

The main purpose of this study was to test experimental cements (Patent accepted September 4th, 2023: BR102021026394–6) doped with a silicate-based bioactive glass nanoparticle (NanoBiosilicate), which were synthesized by a sol-gel Stöber method and a synthetic β-tricalcium phosphate as repairing bioactive materials associated with water or chlorhexidine. Chlorhexidine was also proposed as a vehicle for the experimental composition because of its known anti-enzymatic activity [17], [18], broad-spectrum antibacterial activity [19], [20], and the ability to reactive interact with apatite minerals [21]. The physicochemical properties, cellular interactions, ultrastructural association with radicular dentin, and the ability to induce apatite formation of the experimental NanoBiosilicate (NanoB-H2O and NanoB-CHX) materials were evaluated against existing resin-based and calcium silicate-based endodontic products.