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

Abstract

ObjectiveThe aim of this study was to evaluate the penetration depth of silver into sound and demineralized dentin after application of silver diamine fluoride (SDF). MethodsTwo hundred and eighty-eight dentin specimens were used. The specimens were divided into 3 groups: (1) sound dentin (control), (2) 30min EDTA-treated dentin; and (3) 13h EDTA-treated dentin. SDF was applied to all specimens. Each group was divided into 3 subgroups according to storage time into: 24h, 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. ResultsThe OM showed discoloration in the superficial layer after 24h 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 1200μm inside dentin. Micro-PIXE test detected silver at all time intervals, confirming the EDS depth results. SignificanceIt can be concluded that silver ions can completely infiltrate the demineralized dentin lesion with further penetration into the underlying mineralized dentin.