Colloidal platinum nanoparticles enhance resin-dentin bonding durability

Objectives: This study aims to investigate the effect of colloidal platinum nanoparticles (CPN) on the durability of resin-dentin bonding performance with contemporary adhesives. Methods: Sixty non-carious human maxillary premolars were subjected to microtensile bond strength (mu TBS) testing and divided into two main groups: CPN-treated and untreated. Within each group, specimens were randomly allocated to Clearfil Megabond 2 (MB2), Scotchbond Universal Plus Adhesive with self-etch mode (SESUP), and etch-and-rinse mode (ER-SUP) subgroups (n = 10/group). CPN was applied to dentin in the MB2 and SE-SUP groups for 20 s, followed by rinsing before adhesive application. In the ER-SUP group, CPN was applied after etch-and-rinse. The mu TBS was tested after 24 h, 6 months, and 1 year, and the fracture modes were observed using SEM. The mu TBS data were analyzed using a two-way ANOVA and post-hoc Tukey HSD test (alpha = 0.05). An additional twelve premolars underwent TEM/STEM/EDX for ultra-morphological observations. Results: The application of CPN significantly prevented a decline in the mu TBS of both the MB2 and SE-SUP groups. No significant decrease was observed in the ER-SUP group, either with aging or CPN application. Ultramorphological images revealed platinum nanoparticles attaching to the collagen fibrils of the hybrid layer regardless of aging. It was highlighted that the nanoparticles attached to the banded collagen in the aging groups were observed. Significance: CPN exhibits the potential in enhancing the longevity of resin-dentin bonding in SE mode.