Effectiveness of Silver Diamine Fluoride (SDF) in Arresting Cavitated Caries Lesions

Inclusion Criteria: * Child: * Male or female, between 12-71 months of age at baseline, up to the day the child turns 6 years old. * Must allow examination of the oral cavity and application of treatment by the examiners at baseline. * Must have S-ECC \[defined as: In children younger than age 3, any sign (non-cavitated or cavitated lesion) of caries in any tooth surface (i.e., most common for this age group will be on erupted smooth surfaces). From ages 3 through 5, ≥1 dmfs in maxillary anterior teeth; or a dmfs score of ≥4 (age 3), ≥5 (age 4), or ≥6 (age 5) constitutes S-ECC. Note: The "d" component of the dmfs index is defined as including cavitated and non-cavitated lesions, thus ICDAS\>1\]. * Have at least one SDF-target tooth with * Soft cavitated caries lesions extending into dentin \[ICDAS 5 or 6\]; * Cavitated lesion(s) that allow for direct hardness assessment and application of SDF (microbrush applicator must fit the cavity and be able to access all exposed dentin). * Parent/Legal Guardian: * Provide written informed consent for the child and her/himself prior to participation. * Must be at least 18 years old, or an emancipated minor who provides documentation of emancipation. * Must be willing and able to participate in trial activities. Exclusion Criteria: * Child: * Hereditary generalized developmental dental defects such as Amelogenesis Imperfecta and Dentinogenesis Imperfecta. * Known allergy/sensitivity to silver or other heavy metal ions. * Presence of any gingival or peri-oral ulceration, abscess or stomatitis. * Participating in the foster care system at trial initiation. * Toothache pain at baseline (based on Dental Discomfort Questionnaire score of 1 or higher). * Note: If toothache pain occurs after baseline, the child remains eligible to continue in the trial as long as he/she has at least one trial tooth that meets tooth inclusion/exclusion criteria. * Demonstrated inability to comply with trial protocol requirements (determination is at the Clinical Site Investigator's discretion). * Rickets. * Osteopenia or osteoporosis (e.g., Osteogenesis Imperfecta, Ehlers-Danlos Syndrome, Marfan Syndrome, etc.). * Chronic diseases such as chronic kidney disease, leukemia, lymphoma, rheumatic disorders, etc. * Metabolic bone disease (e.g., Galactosemia, Glycogen Storage Disease Type 1, etc.). * Chronic glucocorticoid, anticonvulsants, chemotherapy, bisphosphonate administration. * Hypothyroidism, hyperparathyroidism, impaired glucose tolerance, hypocalcemia or hypophosphatemia. * Tooth: * Pain due to caries (based on DDQ score of 1 or higher). * Note: If toothache pain occurs after baseline, the tooth is removed from the study. * Pulpal exposure, or signs of pulpal infection (abscess, fistula, swelling). * Mobility not associated with expected exfoliation patterns. * Parent/Legal Guardian: * Demonstrated inability to comply with trial protocol requirements (determination is at the Clinical Site Investigator's discretion). * Inability to read and comprehend the consent document or trial questionnaires in the translated languages available.