Morphological and elemental analysis of silver penetration into sound/demineralized dentin after SDF application

Abstract Objective The aim of this study was to evaluate the penetration depth of silver into sound and demineralized dentin after application of silver diamine fluoride (SDF). Methods Two hundred and eighty-eight dentin specimens were used. The specimens were divided into 3 groups: (1) sound dentin (control), (2) 30 min EDTA-treated dentin; and (3) 13 h EDTA-treated dentin. SDF was applied to all specimens. Each group was divided into 3 subgroups according to storage time into: 24 h, 2 weeks and 1-year storage time. Each subgroup was further divided into four subgroups (n = 8) according to different examinations as optical microscope (OM) observation, scanning electron microscopic (SEM) observation, elemental analysis with energy dispersive spectroscopy (EDS) and Micro-PIXE test. Results The OM showed discoloration in the superficial layer after 24 h and keep extending deeper after 2 weeks and 1-year. SEM showed silver crystals within dentinal tubules after 2 weeks and 1-year. EDS analysis can detect silver penetration only in the 1-year group reaching around 1200 μm inside dentin. Micro-PIXE test detected silver at all time intervals, confirming the EDS depth results. Significance It can be concluded that silver ions can completely infiltrate the demineralized dentin lesion with further penetration into the underlying mineralized dentin.