Restricted accessResearch articleFirst published online 2026-3
Cerium Oxide Nanoparticle Loaded with Toluidine Blue as Cavity Disinfectant Activated via Light-Emitting Diode on the Shear Bond Strength and Resin Tag Length of Universal Adhesive: A Scanning Electron Microscope-EDX Study
Chlorhexidine digluconate (CHX), toluidine blue (TB) photosensitizer (PS), and cerium oxide nanoparticles (CeO2NPs) loaded with TBPS (TB-CeO2NPs) activated via light-emitting diode (LED) on the shear bond strength (SBS) and resin tag length (RTL) of universal adhesive (UA) bonded using self-etch (SE) and etch-and-rinse (ER) approaches to the carious affected dentin (CAD).
Methodology:
A total of 66 mandibular molars were collected, and CAD was identified after the International Caries Detection and Assessment System (ICDAS) criterion 4 or 5. Subsequently, the specimens were allocated into three cohorts based on CAD disinfection protocol (n = 22): Group 1: CHX, Group 2: TBPS, and Group 3: TB-CeO2NPs. Each group was further distributed into two subgroups based on the mode of application of UA, used (n = 11) in each: ER technique (A) and SE technique (B). Composite restorations were built, and all teeth were subjected to artificial aging. One pair of teeth from each cohort underwent RTL assessment via scanning electron microscope. Nine samples were used for SBS and fracture pattern examination via a universal testing machine and a stereomicroscope. One-way ANOVA and post hoc Tukey test were used to compare the means among the different investigated groups (p < 0.05).
Results:
The longest RTL (97.59 ± 1.96 μm) and highest bond strength (11.79 ± 0.83 MPa) were observed in Group 3B (TB-CeO2NPs-SE-UA) samples. Whereas the shortest resin tags (59.70 ± 1.01 μm) and lowest bond integrity (8.56 ± 0.45 MPa) were identified in Group 2A (TBPS-ER-UA).
Conclusion:
TB-CeO2NPs activated via LED can be used as a suitable alternative for CAD disinfection. UA bonded using ER and SE techniques displayed no significant difference in the RTL and bond strength outcomes.
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