This study is being conducted to test whether the use of diammine silver fluoride (also called silver diamine fluoride) hardens the cavity sufficiently so that it arrests.

Phase III RCT with two arms: (1) 38% diammine silver fluoride; (2) distilled fluoride free water. Subjects are 200 preschool children in good general health with untreated tooth decay. Intervention is topical application of the study drug to the open cavity. Primary outcome is caries activity at 14-21 days.

Inclusion Criteria:

• Nyvad criteria 3
• Active carious lesion

Exclusion Criteria:

• Allergy to silver
• Stomatitis or oral ulcerative condition
• Weight less than 15 kg

The primary focus of the adverse events clinical examination was to detect intramural soft tissue changes 2 days following the localized treatment of the teeth. It was not measured 14-21 days later when the primary outcome was assessed.

Primary focus of adverse event assessment was intramural changes associated with the localized topical treatment of the teeth ((infection, inflammation, ulceration).