## 4 Discussion
As this occurs, hydroxide ions (OH\({}^{-}\)) are substituted with fluoride ions (F\({}^{-}\)), resulting in the formation of either fluorapatite or fluoridated hydroxyapatite [10]. This process represents the important role of fluoride in protecting tooth enamel by promoting the formation of more resistant and caries-resistant mineral compounds on the tooth's surface [28; 29]. Similarly, these findings have also shown that the utilization of CO\({}_{2}\) laser irradiation in conjunction with TF leads to a notable increase in the VH and a significant enhancement in bond integrity. The previous research by [PERSON] et al. and [PERSON] and coworkers has substantiated the result of the current inquiry and has elucidated the collaborative impact of laser irradiation and fluoride application in impeding enamel demineralization and facilitating the transformation of hydroxyapatite into fluorapatite [31; 32]. This results in the improved bond integrity and microhardness of the eroded surfaces. Furthermore, these outcomes have indicated that Curodont(tm) Repair showed a significantly lower VH and bond strength among the groups tested with remineralizing agents. The literature has demonstrated the dubious and contradictory impact of Curodont(tm) Repair on the bond strength and microhardness of decalcified enamel surfaces [17]. However, the reported outcome of the existing study can be attributed to the development of a hydrophobic surface after the application of Curodont(tm) Repair, potentially impeding the bonding of the resin to dentin [33; 34]. Regarding the failure mode, it was observed that the bond failures that were seen were primarily cohesive or mixed, regardless of the specific dentin pretreatment method employed. Cohesive failure refers to a situation where a material fractures or breaks within itself, rather than at the interface with another material [35; 36]. The failure occurs due to the weaknesses or limitations present within the material's structure. This type of failure indicates that the material's internal cohesion is insufficient to withstand the applied forces or stresses, leading to its fracture or separation [37; 38], whereas mixed failure occurs when both adhesive and cohesive failures are present, due to a combination of factors related to the material properties, bonding strength, stress distribution, and environmental conditions. This study has several acknowledged limitations. Firstly, it lacks a positive control (sound enamel) for assessing the efficacy of remineralization treatment. Secondly, there is a deficiency in long-term assessments regarding how remineralizing agents affect the microhardness (VH) and bond strength of composite restorations. This absence impedes a comprehensive understanding of the enduring effects of these agents. Additionally, the chosen experimental model inadequately replicates the impact of dentinal fluid on the degradation of the resin composites, potentially limiting the study's ability to fully simulate real-world conditions. The inclusion of supplementary analyses, particularly an evaluation of the mineral content and permeability, could have provided valuable insights into the effects of the remineralizing agents. Furthermore, the study could have benefited from employing advanced imaging techniques, such as scanning electron microscopy (SEM) and atomic force microscopy (AFM), to assess the changes in the surface topography following the application of the latest remineralizing agents.