IADR Abstract Archives
Zinc in Silver Diamine Fluoride Treated Carious Teeth
Objectives: Silver diamine fluoride (SDF) is thought to arrest progression of dental caries. However, the mechanism by which SDF arrests dental caries is not well understood. We hypothesize that SDF creates a mineralized barrier reinforced with zinc (Zn) expressed by odontoblasts. The objective of this study was to investigate spatial variation of Zn in carious teeth treated with SDF over time.
Methods: Carious primary teeth with no SDF (n=3), one SDF application for 60 seconds immediately upon extraction (n=3), one SDF application and subsequent extraction after 3 weeks (n=3), and multiple SDF applications over the course of one year prior to extraction (n=1) were chosen to spatially colocalize P, Zn, and Ag elements. The same samples of SDF treated carious lesions were examined using back scattered electron microscopy (BSE), energy dispersive X-ray spectroscopy (EDX), and microprobe synchrotron X-ray fluorescence spectroscopy (XRF) to correlate and colocalize elements.
Results: Figure: Correlative maps of BSE (A) and EDX (B) illustrated occluded dentin tubules either with Ag (green) or apatite (red) particles. Ag representative of SDF (C-row 1, white) was identified in all specimens. However, Zn was identified in separate layers and was indicative of the temporal effect (C-rows 2 and 3, green). Spatial maps of higher counts of elemental Zn were localized around caries and pulp regardless of SDF treatment (Fig. C). However, SDF treated specimens contained regions of significantly higher counts of Zn and P in tertiary dentin farther from the pulp chamber and predentin around pulp (D).
Conclusions: Based on spatiotemporal correlative maps and co-localization of Zn and P, SDF treated teeth also were reinforced with mineral containing Zn. Presence of Zn could be a response to caries activating the inflammatory pathway with matrix metalloproteases (MMPs) and tissue nonspecific alkaline phosphatase (TNAP) to promote cell-based biomineralization.
Methods: Carious primary teeth with no SDF (n=3), one SDF application for 60 seconds immediately upon extraction (n=3), one SDF application and subsequent extraction after 3 weeks (n=3), and multiple SDF applications over the course of one year prior to extraction (n=1) were chosen to spatially colocalize P, Zn, and Ag elements. The same samples of SDF treated carious lesions were examined using back scattered electron microscopy (BSE), energy dispersive X-ray spectroscopy (EDX), and microprobe synchrotron X-ray fluorescence spectroscopy (XRF) to correlate and colocalize elements.
Results: Figure: Correlative maps of BSE (A) and EDX (B) illustrated occluded dentin tubules either with Ag (green) or apatite (red) particles. Ag representative of SDF (C-row 1, white) was identified in all specimens. However, Zn was identified in separate layers and was indicative of the temporal effect (C-rows 2 and 3, green). Spatial maps of higher counts of elemental Zn were localized around caries and pulp regardless of SDF treatment (Fig. C). However, SDF treated specimens contained regions of significantly higher counts of Zn and P in tertiary dentin farther from the pulp chamber and predentin around pulp (D).
Conclusions: Based on spatiotemporal correlative maps and co-localization of Zn and P, SDF treated teeth also were reinforced with mineral containing Zn. Presence of Zn could be a response to caries activating the inflammatory pathway with matrix metalloproteases (MMPs) and tissue nonspecific alkaline phosphatase (TNAP) to promote cell-based biomineralization.
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