Effect of Silver Diamine Fluoride on Caries of Deciduous Teeth

Objectives: Clinical studies have shown that the topical application of silver diamine fluoride (SDF) can effectively treat and arrest dental caries. Even though SDF leaves an undesirable dark stain on the tooth surface, this noninvasive, easy-to-use, and inexpensive treatment can significantly impact the oral health of children, particularly children with severe caries, special medical needs, and limited access to dental care. Clinically, SDF is proven to arrest caries in deciduous teeth; however, the mechanism on how SDF attacks the carious lesion is unclear. This study aimed to determine and measure the degree of SDF penetration and precipitation on deciduous teeth with caries.
Methods: Ten deciduous incisors that were extracted due to caries were collected, disinfected with 0.1% thymol, and rinsed with phosphate-buffered saline (PBS). Each tooth was air-dried and treated with 38% SDF solution according to UCSF's standard protocol. The teeth were dehydrated, embedded in poly-methyl-methacrylate, and sectioned through the carious lesion. The surfaces were imaged via quantitative backscattered electron-scanning electron microscopy (qBSE-SEM) and examined by energy dispersive X-ray spectrometry (EDX) to identify and quantitatively measure Ag precipitate within the enamel/dentin.
Results: The qBSE-SEM examination clearly demonstrated that Ag precipitation was positive in demineralized enamel rods and dentin tubules. Ag precipitation occurred as deep as 1,509.42 μm into the dentinal tubules. Analysis of the EDX results depicted Ag precipitation in areas associated with the carious lesions, on average, 52.5% (range from 34.4%-64.0%) of the demineralized dentin. The measurements clearly showed that the larger the area of demineralization, the greater the area of SDF penetration. We also found that Ag deposited on the surface of acquired dental pellicle, but it did not penetrate into the dentin layer underneath sound enamel. In addition, mineralized caries-free areas appeared to be negative for Ag precipitate.
Conclusions: Application of 38% SDF was found to form a dense precipitate layer on the deciduous tooth surface, with the greatest localization within demineralized structures of the caries lesion. Its mode of action for arresting caries progression needs further study.