Dentin tubule occlusion by a 38% silver diamine fluoride gel: an in vitro investigation

Abstract

Objective: Silver diamine fluoride (SDF) is effective in treatment of dentin hypersensitivity and caries lesions. However, the non-viscous solution does not easily allow clinicians to control the application area. A 38% SDF experiment gel was compared in vitro to commercial SDF for its ability to penetrate and occlude dentinal tubules.

Materials and methods: Human root surface dentin specimens were treated with gelled or standard 38% SDF or negative control. Penetration behavior was established by Drop Shape Analysis. Precipitates at the surface and within tubules were analyzed by SEM and EDX after treatment; Results: penetration depths up to 500 µm were observed for both SDF formulations. Both formulations occluded dentinal tubules similarly. Precipitates on the dentin surface and within dentinal tubules were found for both SDF formulations, with a slight tendency for the experimental gel SDF product to be more abundant than the commercially available one.

Discussion: behavior of the experimental 38% SDF gel formulation appeared indistinguishable from the commercial 38% SDF product with respect to dentinal tubule penetration and occlusion.

Conclusions: The experimental 38% SDF gel may be a suitable intervention for the prevention of dentin hypersensitivity.

Conflict of interest statement

AK, MM, and FL did not receive remuneration for the preparation of the manuscript. PM is a member of Advantage Silver Dental Arrest LLC. JMT is a scientific consultant to Advantage Silver Dental Arrest LLC.

© 2022. The Author(s).

Figures

Fig. 1. Relative drop volume over time for the experimental SDF gel and positive control.

The value of the relative drop volume is related to the respective initial volume of the drop (which is set as 100%).

Fig. 2. Representative surface imaging by SEM at a magnification of 2500× in backscattered electron mode (material contrast) of treated dentin samples are shown in the upper row.

The chemical element mapping is performed using the silver signal. a, b Show the experimental formulation (sample A2), (c) and (d) the placebo (sample B2) and (e) and (f) the positive control (sample C2). The lower row shows element maps of the corresponding SEM-micrographs of upper row. Scale bar = 25 µm.

Fig. 3. Representative surface images by SEM at a magnification of 25,000× in backscattered electron mode (material contrast) of treated dentin samples (from left: A2, B2, C2).

Occluded tubules are visible in 3a and 3c; open tubules are visible in 3c. Scale bar 2.5 µm.

Fig. 4. Representative cross section images of fractured dentin samples by SEM in backscattered electron mode: images of the upper row show an overview (scale bar corresponds to 100 µm), whereas images of the lower row depict a detailed view in higher magnification (scale bar corresponds to 20 µm).

a, b Show the experimental formulation (sample A1), (c) and (d) the placebo (sample B3) and (e) and (f) the positive control (sample C1). The samples surface is indicated by arrows.