## 1 Introduction  
Glass ionomer cements (GICs), developed during the late 1960s [1], are one of the most important groups of dental materials due to their ionic exchange with the dental substrate and their continuous fluoride release. GICs do not mimic tooth color or composites and show faster surface loss with wear. However, because they are less technique-sensitive, they may act as the material of choice in many restorative cases [2]. On the other hand, GICs not only possess a remineralizing action but can also increase their hardness in contact with the oral environment over time, and their ability to incorporate calcium and phosphate has been demonstrated by SEM-EDX, suggesting an additional mineralization process [3]. The main disadvantages attributed to GICs are their poor mechanical properties [4], poor esthetics due to their lack of translucency [5], and moisture sensitivity while setting [6]. GICs have undergone multiple modifications in their structure and composition to overcome these disadvantages, increasing their usefulness as restorative materials in dental treatments [7]. Among these modifications, the following can be highlighted: the incorporation of resin, usually 2-hydroxy-ethyl methacrylate (HEMA) [8]; metallic fiber particles [9; 10], such as titanium dioxide, zirconia, or alumina nanoparticles [11; 12; 13]; and other inorganic compounds, such as hydroxyapatite, fluorapatite, or bioactive glass [14; 15]. Resin-modified glass ionomer cements (RMGICs) were developed to improve the physical and mechanical properties of GICs [16]. These materials undergo a dual-setting reaction, the typical acid-base reaction of GICs, and photopolymerization [17]. The remineralizing potential of RMGICs can be improved by incorporating bioactive glasses into their composition, which also confer bioinductive and regenerative potential to the material [18]. The calcium-fluor-aluminosilicate content in the glass powder is responsible for the remineralizing ability of the materials [19]. Fluoride promotes the formation of fluorapatite, which is less soluble than hydroxyapatite [20]. When fluoride ions are released, they can saturate the liquid phase in and around the surface of the restorative tooth, resulting in the precipitation of CaF\({}_{2}\) crystals, which reduces the chances of demineralization and accelerates the remineralization process [21]. This process can be considered bioactive [22]. An in vitro study demonstrated that at 37 \({}^{\circ}\)C, maximum fluoride release was observed from Equia Forte HT filling, regardless of pH conditions [23]. Modified forms of glass ionomers are available in the form of resin-modified glass ionomer cements (RMGICs) [24], zirconia-reinforced glass ionomers [25], nano-filled modified GICs [26], bioactive glasses [27], and glass carbonsers [24]. During the setting process, resin composite materials may undergo shrinkage, which causes difficulties in effectively sealing against the tooth surface, potentially leading to the infiltration of bacteria [28]. This phenomenon, known as microleakage, is frequently manifested as marginal staining, postoperative sensitivity, and the development of secondary caries around the restoration site [29]. Applying an elastic shrinking material layer combined with bulk fill composite reduces the stress magnitude in dentin and enamel to replace dental tissues in Class I and II posterior cavities [30]. On the other hand, less microleakage was reported from Equia Forte in Class II restorations than with GC G-aenial Posterior in an in vitro study [31]. The current minimally invasive treatment approach involves removing infected dentin but preserving affected tissue that is partially demineralized [32]. The dentin remineralization process involves a complex mechanism of mineral gain and its interaction with the collagen matrix [33].