AIMTo assess the effect of CAD surface conditioners and their effect on Ra and SBS of tooth-colored filling material adhered to CAD surface with adhesive modified with 1 % Sep-NPs. Also, the DC of modified EA and its effect on the rheological properties. METHODSNinety human molars with carious extension up to the middle third of occlusal dentin were included. The teeth were then arbitrarily allocated into three groups based on the type of surface conditioning received (n=30) Group 1 (PA), Group 2 (FS laser), and Group 3 (Ery PS). Ten samples from each group underwent Ra analysis using a stylus profiler. Twenty samples from each cohort were distributed into two subcategories based on the application of unmodified EA (A) and Sep-infiltrated EA (B). Composite restoration was built followed by SBS and failure mode analysis. Scanning electron microscopy and Energy dispersive X-ray EDX were assessed of sepiolite NPs. Degree of conversion (DC) and rheological analysis of the modified adhesive and unmodified adhesive were also performed. One-way analysis of variance (ANOVA) and the Tukey post hoc test were employed to conduct comparisons between the different groups RESULTS The highest score of Ra and bond strength were displayed by Group 1B (PA + Sep-NPs filled EA) (17.32 ± 1.43 MPa) samples. Nevertheless, the lowest values were established by Group 3A (Ery-PS + EA) (13.45 ±0.80 MPa) treated teeth. An increase in Ra resulted in a rise in SBS.DC decreased with the incorporation of 1% Sep-NPs in EA compared to unmodified EA. CONCLUSIONConditioning of CAD with PA and FS laser shows high surface roughness and favorable adhesion to experimental adhesive modified with 1% Sep-NPs. Modified adhesive with 1% Sep-NPs decreases DC and rheological properties.