Influence of Different Cavity Disinfection Protocols on Adhesion at the Resin Composite–Dentin Interface
Polymers. 2026;18(9):1011.
ABSTRACT
This study evaluated the effects of four cavity disinfection protocols on microtensile bond strength (µTBS) and failure mode of dentin bonded with a universal adhesive in self-etch mode. Sixty human third molars were assigned to five groups (n = 12): Control (Clearfil S3 Bond Universal), Clearfil SE Protect Bond (CPB, MDPB-containing), 2% chlorhexidine (CHX), 5.25% sodium hypochlorite (NaOCl), and 200 ppm hypochlorous acid (HOCl). After disinfectant application and bonding, composite build-ups were sectioned into beams (≈0.9 mm2) and tested as immediate (24 h) and thermocycled (10,000 cycles) subgroups. Data were analyzed using two-way ANOVA, Tukey HSD, and chi-square/Fisher's exact tests (α = 0.05). At 24 h, NaOCl and CHX produced significantly lower µTBS than the control, HOCl, and CPB groups (p < 0.05). After thermocycling, Control, CPB, and NaOCl declined significantly, while CHX remained stable (p = 0.960) and HOCl showed non-significant reduction (p = 0.086). NaOCl yielded the highest adhesive failure rate and lowest bond strength. CHX reduced initial µTBS but maintained stability. HOCl and CPB produced values comparable to controls, though HOCl was more aging-susceptible. MDPB-containing adhesives may preserve bond durability while providing disinfection.
KEYWORDS
cavity disinfectant · chlorhexidine · hypochlorous acid · microtensile bond strength · universal adhesive
STUDY SUMMARY
This laboratory study on extracted human third molars compared four cavity disinfection protocols against an untreated control for their effect on the microtensile bond strength of dentin bonded with a universal adhesive in self-etch mode, tested at 24 hours and after 10,000 thermocycles. Sodium hypochlorite and chlorhexidine lowered initial bond strength, and after thermocycling the control, MDPB-containing adhesive and sodium hypochlorite groups declined while chlorhexidine remained stable; sodium hypochlorite showed the lowest bond strength and the highest adhesive failure rate. Under these conditions, hypochlorous acid and the MDPB-containing adhesive gave values comparable to the control.