Non-carious cervical lesions (NCCLs) are prevalent defects characterized by the loss of tooth structure at the cementoenamel junction, resulting from multifactorial aetiological factors excluding dental caries [1]. Such cervical lesions can compromise the structural integrity of tooth leading to hypersensitivity, pulp exposure, and even aesthetic issues [2]. The multifactorial aetiological factors of NCCLs include abrasion, erosion, and attrition from occlusal stresses [2,3] with ongoing debate regarding the predominant process [[4], [5], [6]].

Restoring NCCLs presents several challenges, including isolation of gingival sulcular fluids, and managing cervical tooth flexure under masticatory force, which can lead to restoration dislodgement [2]. Therefore, materials with an elastic modulus similar to that of dentin are preferred [2,7]. Furthermore, adhesion of tooth colored restoration to such non-retentive lesions is a major challenge that has been emphasized extensively in dental literature [2,7,8]. NCCLs exhibit structural differences from normal dentin due to frequent exposure to the oral environment, resulting in a heterogeneous, non-permeable, hypermineralized surface layer that complicates hybrid layer formation [8]. In line with this context, loss of retention of up to 50 % in NCCLs restorations has been reported in clinical research [9].

Therefore, several attempts were conducted to optimize the sclerotic dentin surface for bonding procedure, including chemical pretreatment with phosphoric acids, and ethylenediamine tetra acetic acid EDTA and mechanical roughening with diamond burs [[8], [9], [10], [11], [12], [13], [14], [15]]. Recently, laser pretreatment has been proposed to enhance bonding to sclerotic dentin [16,17]. Among laser types, the erbium-doped yttrium aluminum garnet (Er:YAG) laser and neodymium-doped yttrium aluminum garnet (Nd:YAG) laser are the most commonly used lasers in the field of adhesive dentistry [18] Moreover, Low level laser therapy (LLLT) like diode laser (DL) has gained a wide acceptance due to its safety and ease of use [17,19].

By reviewing the currently available literature, it was obviously noticing contradicting evidence regarding the efficacy of these pretreatments. Several studies advocate for mechanical roughening, citing its ability to remove the hypermineralized surface layer and significantly improve restoration retention in NCCLs [8,9,13]. Conversely, other studies have reported no significant effect of dentin mechanical roughening in relation to bond strength and retention rates [10,12,20]. Similarly, one study reported that sclerotic dentin pretreatment with 15 % EDTA for 60 s showed an acceptable bond strength [21], while another study presented contradictory findings [22].

Regarding laser pretreatment, there is no consensus in the literature on the most effective laser type for maximizing bond strength to cervical non-carious sclerotic dentin. Therefore, this systematic review of in vitro studies aims to evaluate and compare the effects of various surface pretreatments on the bond strength of resin composite to cervical non-carious sclerotic dentin. Specifically, it addresses the research question: "Does surface pretreatment of cervical non-carious dentin enhance bond strength to resin composite?" The objective is to elucidate the impact of different pretreatment approaches on the bond strength of composite resin restorations.