## 1 Introduction  
The practice of restoring teeth following partial caries removal (PCR) has become widely accepted in modern dentistry [1]. The ideas of minimal intervention dentistry are founded upon the concept of selectively removing infected dentin while maintaining caries-affected dentin (CAD) [2]. Streptococcus mutans (_S. mutans_) is the primary bacterium implicated in the development of dental caries [2]. The significance of the bonding process in restorative dentistry has led to extensive research to examine the bond integrity at the resin-dentin interface [3]. Insufficient bond strength and microleakage are two critical variables that exert a substantial influence on the longevity of adhesive restorations, ultimately leading to undesirable restorative failures [2]. It is important to acknowledge that these failures are usually due to the tendency of resin-based materials to experience considerable dimension change and the development of internal tension during the polymerization process [4]. The utilization of self-etch adhesives (SE) has gained significant popularity as a result of their ability to effectively minimize post-operative irritation. SE adhesives involve the incorporation of acidic functional monomer which serves to enhance chemical adhesion and bond durability [5]. However, it is important to note that this method does not exhibit superior bond strength when compared to the phosphoric acid etch-and-rinse adhesive technique [6]. Therefore, it was considered imperative to develop a nano-engineered solution to address the inherent flaws of the etch-and-dry technique and improve the antimicrobial potency of adhesive restorations. In the past, efforts have been made to include drugs in dental materials to improve their microbiological properties while preserving existing mechanical and physical benefits [7; 8]. Recently, the combination of zirconia/silver phosphate (ZrO\({}_{2}\)/Ag\({}_{3}\)PO\({}_{4}\)) nanoparticles (NPs) has piqued the interest of researchers, primarily because of the synergistic benefits that silver and zirconium NPs offer [9]. In the realm of medical and pharmaceutical nano-engineering, silver nanoparticles (AgNPs) have garnered considerable attention due to their remarkable ability to effectively combat a wide spectrum of bacteria while exhibiting relatively low cytotoxicity when compared to other metal nanoparticles [10; 11; 12; 13]. The available scientific literature has underscored the potential of Ag\({}_{3}\)PO\({}_{4}\) (silver-phosphate) to eliminate both bacteria and fungi. However, it has been proposed that the mechanical and antibacterial efficacy of Ag\({}_{3}\)PO\({}_{4}\) can be significantly enhanced through its integration with other types of nanoparticles [14; 15]. Zirconium oxide (ZrO\({}_{2}\)) boosts commendable characteristics, including high strength, exceptional toughness, excellent resistance to corrosion, low toxicity, compatibility with biological systems, and inherent antibacterial properties [16]. The inclusion of ZrO\({}_{2}\) in various materials or matrices has demonstrated its ability to improve fracture toughness, flexural strength, shear bond strength, and optical properties [17]. Nonetheless, there is a noticeable dearth of research on the impact of ZrO\({}_{2}\)/Ag\({}_{3}\)PO\({}_{4}\) NP-modified self-etch (SE) adhesives concerning their antibacterial potential against \(S\). _mutans_ and their micro-tensile bond strength (\(\upmu\)TBS) to CAD surfaces, necessitating further investigation in this area. Based on the existing body of indexed literature, it was observed that data related to the effect of different concentrations of ZrO\({}_{2}\)/Ag\({}_{3}\)PO\({}_{4}\) NPs incorporated in SE adhesive against S. mutans and \(\upmu\)TBS have not been reported yet.