## 1 Introduction  
Erosion, described as a non-caries lesion resulting from the dissolution of hard tissues via acids that are not bacterial by products, is characterized as a progressive condition [1]. Initially, the weakening of the enamel tissue occurs due to wear and attrition, while prolonged exposure to extrinsic or intrinsic acids disrupts the remineralization-demineralization balance over time, potentially affecting the underlying dentin tissue [2]. In dentin erosion, due to the acidic pH, dentin demineralization occurs, exposing collagen fibrils, and the endogenous collagenolytic activity (MMP) present in dentin and saliva begins to function [1]. The suppression of this MMP, which contributes to the degradation of the hybrid layer formed by adhesive restorations, holds significance for the longevity of restorations achieved via the use of inhibitory agents [3]. Specific MMP inhibitors, such as chlorhexidine (CHX) or galardin, can potentially slow down the degradation in the hybrid layer by suppressing collagenolytic and gelatinolytic activity [4; 5]. Several analyses have revealed the significant role of endogenous enzymes such as MMP-2, -8, and -9 in dental caries or dental erosion, demonstrating their involvement in the process of degradation [6; 7; 8]. Recent research has indicated that a-tomatine, a glycoalkaloid found in tomatoes, can inhibit MMP-2 and MMP-9 activation in certain cancer cells, displaying anti-metastatic effects [9; 10]. The MMP activity in dentin can be detected through various and costly techniques, such as in situ zymography [11], SDS-PAGE [5], or the mass loss measurement of collagen degradation [12].  
Molecular docking is a computational chemistry method used to predict the binding affinities of ligands to protein structures such as enzymes and receptors [13]. In this method, each of the ligands is rotated around the rotatable bonds (i.e., their various conformations are changed) and approximated to the actual protein-ligand complex via a complete, systematic search for its orientation and position [14; 15]. The results obtained are important in terms of providing guidance for in vitro and in vivo results. The molecular docking method has been accepted by most scientific authorities since the early 2000s to shed light on experimental results [13; 16; 17; 18]. The movements of atoms, both interactions with each other and with the solvent in the physiological environment, are included in the molecular dynamics calculation method [19]. This makes computational chemistry a set of methods whose accuracy continues to improve as technology is developed [15]. According to the literature, there is no existing study within the dental literature regarding the potential utilization of a-tomatine as an MMP inhibitor, and furthermore, an in silico approach (molecular or dynamic docking) to assess the effectiveness of a-tomatine on MMP enzymes has not been applied.  
In light of this information, the present study aimed to scrutinize the application of a-tomatine and chlorhexidine (Figure 1) as MMP inhibitors in both sound and eroded dentin tissues, investigating their immediate and long-term (6-month) effects on adhesive bond strength. Furthermore, the intention behind this was to substantiate, through both molecular and dynamic docking methods, the enzymatic relationship of these two agents with MMP-2, -8, and -9. The formulated hypotheses were as follows: (1) The bond strength values in sound dentin are higher compared to those of eroded dentin. (2) a-tomatine is equally efficacious as chlorhexidine in terms of MMP inhibition.