Evaluation of the effect of two biomimetic approaches on micro-tensile bond strength of one etch & rinse adhesive to dentin (An in vitro study)

Background Hydrolytic and enzymatic degradation of the resin–dentin interface compromises the longevity of adhesive restorations. Biomimetic strategies for guided dentin remineralization, including self-assembling peptide P11-4 (Curodont Repair™) and the polymer-induced liquid precursor (PILP) process using poly-L-aspartic acid, have been proposed to stabilize the collagen matrix and enhance adhesive bond durability. Methods Fifty-four extracted human molars were artificially demineralized and randomly assigned to three pretreatment groups ( n = 18 each): control (no pretreatment), self-assembling peptide P11-4 (Curodont Repair™, Credentis AG) applied for 5 min, or polymer-induced liquid precursor (PILP) solution containing 100 μg/mL poly-L-aspartic acid applied for 1 h. Each group was subdivided according to storage time in artificial saliva (24 h, 3 days, or 14 days) ( n = 6 teeth per subgroup). Specimens were restored using an etch-and-rinse adhesive system (Adper Single Bond 2, 3M ESPE) and resin composite. One micro-tensile beam (≈1 × 1 mm 2 ) was prepared per tooth (experimental unit = tooth). Micro-tensile bond strength (µTBS) was measured using a universal testing machine equipped with a 500 N load cell at a cross-head speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Bonferroni post hoc tests ( α = 0.05). Results Two-way analysis of variance revealed significant effects of pretreatment, storage time, and their interaction on µTBS values ( p 0.001). At T0 and T1, specimens pretreated with P11-4 exhibited the highest mean µTBS values, which were significantly greater than those of the PILP group and comparable to or higher than the control group. At T2, the control group demonstrated significantly higher µTBS values, while both biomimetic pretreatment groups showed a significant reduction in bond strength. Failure mode analysis revealed predominantly mixed failures at T0 and T1 across all groups, whereas adhesive failures were more prevalent at T2 in the biomimetic groups; the control group exhibited mixed and cohesive-in-dentin failures. Conclusions pretreatment with the self-assembling peptide P11-4 resulted in higher micro-tensile bond strength to demineralized dentin compared with the PILP approach at early storage periods. However, the durability of both biomimetic dentin remineralization strategies was time-dependent .