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ClearDefense Silver Nanoparticles: Characterisation and Safety Assessment for Children's Dental Care Off-label Use
Stacey L Harper1, Marilyn R Mackiewicz2
1Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, USA; School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, USA; Oregon Nanoscience and Microtechnologies Institute, Corvallis, OR, USA.
Background And Objectives:
We characterised an Ag-Chitosan-NaF product (ClearDefense), marketed for off-label use in caries arrest in children, as an alternative to 38% silver diamine fluoride (SDF). The label lists 0.2% Ag+ and 1.36% F-. No child efficacy or safety studies are reported.
Methods:
We followed U.S. National Institute of Standards and Technology (NIST) guidelines to describe the composition and stability of the product and assess its safety for children.
Results:
The product features heterogeneous AgNPs: 86% irregular spherical (32 ± 26 nm), 6% triangular (101 ± 100 nm), and 8% rod-shaped (42 ± 28 nm length, 16 ± 10 nm width). Ag-Chitosan-NaF exhibits agglomeration with Chitosan and NaF, and stability studies reveal an increase in Ag+ ion concentration upon exposure to air, raising concerns about dosage variations. Toxicity assessment reports a Margin of Exposure (MOE) for preschool children of 8-20 mg/kg, based on application amount and a 100X correction factor.
Clinical Significance:
This Ag-Chitosan-NaF product requires refinement to meet the standards for formulation, purity, and safety for paediatric off-label use.
Conclusions:
ClearDefense differs from the FDA-approved 38% SDF, raising concerns about consistency and paediatric suitability. A thorough reassessment by the manufacturer is needed to meet paediatric clinical standards.
