Diffusion of Silver Diamine Fluoride Solution in Dentine: An In Vitro Study

Area of Science:

• Dental Materials Science
• Biomaterials
• Nanotechnology

Background:

• Silver diamine fluoride (SDF) is a widely used topical agent for arresting caries.
• Understanding ion diffusion dynamics is crucial for predicting its efficacy and safety.
• Dentine thickness and its tubular structure are key factors influencing substance penetration.

Purpose of the Study:

• To evaluate the diffusion patterns of silver and fluoride ions through bovine dentine over 24 weeks following 38% SDF application.
• To investigate the influence of dentine thickness on the rate and extent of ion diffusion.
• To correlate dentinal tubule characteristics with ion permeability.

Main Methods:

• Bovine dentine discs of varying thicknesses (0.5, 1.0, 1.5 mm) were prepared.
• Dentine discs were subjected to topical application of 38% SDF solution.
• Silver and fluoride ion concentrations in collected deionized water were measured weekly for 24 weeks using generalized estimating equations.

Main Results:

• Ion diffusion through dentine plateaued around 4 weeks and declined thereafter.
• Cumulative 24-week silver diffusion was 20 (group 1), 10 (group 2), and 5 (group 3) μg.
• Cumulative 24-week fluoride diffusion was 18 (group 1), 13 (group 2), and 7 (group 3) μg, with significant differences across thicknesses (P < .05).

Conclusions:

• Silver and fluoride ion diffusion through dentine exhibits a decreasing trend over 24 weeks.
• Dentine thickness and dentinal tubule characteristics significantly influence ion diffusion dynamics.
• Reduced dentine thickness correlates with increased silver and fluoride ion diffusion towards the pulp.