## 1 Introduction  
Human enamel is the hardest layer of the tooth and is highly structured [1]. Teeth are naturally protected by a layer of salivary pellicle, which possesses the ability to neutralize the demineralization effect caused by a low pH [2]. Erosion of the tooth surface can be caused by both intrinsic and extrinsic factors, i.e., the consumption of acidic food and acidic beverages and acid reflux in patients with gastroesophageal reflux disease (GERD) [3]. A prolonged exposure to erosive substances exacerbates the demineralization of tooth surfaces, resulting in decreased levels of essential inorganic mineral ions, such as fluoride, calcium, and phosphate [4]. Therefore, a carefully performed restorative treatment becomes necessary when erosive wear worsens the tooth's structural integrity [5]. The existing research has emphasized the prevention of demineralization and the promotion of remineralization before restoring the tooth [6; 7]. There are two main types of remineralization technology used in dentistry techniques, including those that improve fluoride effectiveness and those that mimic the natural healing mechanisms [8; 9]. Fluoride facilitates tooth remineralization by fostering the creation of fluorapatite crystals on partially demineralized sub-surface crystals [10]. Likewise, the utilization of lasers in contemporary dentistry has seen substantial expansion [11]. Previous experimental studies have shown that CO2 laser irradiation can cause melting and subsequent recrystallization in dental hard tissues, leading to an enhanced resistance to acidic substances [7; 12]. Laser irradiation has been proposed as a method to improve the effectiveness of topical fluoride treatment by increasing fluoride absorption into the enamel and promoting the conversion of hydroxyapatite into fluorapatite crystals [13; 14]. Nonetheless, it is important to note that both of these techniques are limited to the remineralization of the tooth and cannot fully regenerate the lost tooth structure. Consequently, there is an ongoing endeavor to shift from reparative approaches to regenerative biomineralization therapies, which have the potential to promote the growth of structured apatite crystals. Curodon(tm) Repair, which is formulated using proprietary CUROLOX technology, was developed to promote enamel regeneration. The active ingredients in Curodon(tm) Repair include fluoride, sodium chloride, calcium phosphate, and oligopeptides [15]. It also contains a self-assembled peptide matrix P11-4 that promotes the creation and the deposition of hydroxyapatite crystals on enamel [16; 17]. These peptides can mimic the natural process of enamel formation by attracting calcium and phosphate ions to facilitate the growth of hydroxyapatite crystals on the tooth's surface [18]. By promoting the deposition of hydroxyapatite, such peptides help to repair and strengthen the enamel, which can be eroded or damaged by factors such as acidic foods, bacteria, and mechanical wear [19; 20]. Furthermore, pioneering research has unveiled a novel two-component NR-5(tm) technology that combines calcium silicate and sodium phosphate [18]. This groundbreaking technology is purported to create a crystal structure closely resembling hydroxyapatite, the predominant mineral found in tooth enamel [17]. However, it is worth noting that there is a significant gap in the existing research when it comes to understanding the impact of NR-5(tm) technology and Curodon(tm) Repair on uSBS and VH. Further research is essential in order to conduct a comprehensive and in-depth examination of how these innovations affect these specific properties. The existing scientific literature exhibits a notable dearth of data about the influence of Curodon(tm) Repair and NR-5(tm) technology on micro-shear bond strength (uSBS) and Vickers hardness (VH).