Impact of Dentin Pretreatment With Dimethyl Sulfoxide on Behavior of Resin Composite Restorations in Non-Carious Cervical Lesions

Inclusion Criteria:following eligibility criteria: 1. Presence of at least two permanent teeth with non-carious cervical lesions (NCCLs) requiring restoration. Lesions were confirmed as non-carious Class V cervical defects using the Smith and Knight Tooth Wear Index (scores 2-3) to ensure standardized dentin exposure without pulpal involvement.(3) 2. The selected teeth were required to be free from mobility and exhibit normal pulpal and periapical status, confirmed by the absence of spontaneous pain, tenderness to percussion, clinical signs of pulpal necrosis, and periapical radiolucency on periapical radiographs. 3. Participants were required to have at least 20 natural teeth in occlusion, with the selected teeth in functional occlusion, to ensure adequate occlusal stability, uniform distribution of masticatory forces, and standardized functional loading. 4. The cavity configuration had to present an incisal margin located in enamel and a gingival margin located in dentin. To standardize the dentin-to-enamel bonding substrate, only lesions with ≤50% of the cavosurface margin in enamel were included. 5. The cervical cavity margin had to be equigingival or supragingival. 6. Dentin sclerosis was assessed before enrollment by visual inspection and tactile examination using a dental explorer according to the University of North Carolina (UNC) Clinical Dentin Sclerosis Scale (scores 1-4). To standardize the dentin substrate and minimize substrate-related variability, only lesions with sclerosis scores of 1 or 2 were included 7. Caries risk was assessed using the Caries Management by Risk Assessment (CAMBRA) protocol. Participants classified as having moderate caries risk were eligible for inclusion. A limited number of high-risk participants were also accepted provided that the only high-risk criterion present was "three or more carious lesions or restorations within the previous 36 months." 8. Participants had to be willing and able to comply with the study protocol and attend all scheduled follow-up visits. \- Exclusion Criteria: * Participants were excluded if they presented with poor oral hygiene, chronic periodontitis, were undergoing active orthodontic treatment or periodontal surgery, or had xerostomia or were pregnant. Individuals with systemic conditions that could influence oral or periodontal health (e.g., hypertension, diabetes mellitus, malignancy, or other chronic diseases), or those receiving medications known to affect periodontal tissues or wound healing, were also excluded. In addition, participants exhibiting signs of severe parafunctional habits, including clenching or pronounced occlusal wear facets suggestive of bruxism, were not considered eligible for inclusion.