Preventing Early Childhood Caries With a Silver Diamine Fluoride Gel

Randomized Clinical Trial to Prevent Early Childhood Caries With a Silver Diamine Fluoride Gel

The objective is to compare the efficacy of SDF gel with that of NaF varnish in preventing carious lesions in preschool children when applied at half-yearly intervals over a 24-month period.

Study Overview

• Status: Active, not recruiting
• Conditions: Early Childhood Caries (ECC)
• Intervention / Treatment: Drug: Silver diamine fluoride gel; Drug: Sodium Fluoride varnish

Detailed Description

Aim: The World Health Organization (WHO) included SDF in the WHO Model List of Essential Medicines. SDF is typically available as a 38% aqueous solution, which is runny and difficult to apply. A 38% SDF gel has been introduced but it has not been tested clinically. The objective is to compare the efficacy of SDF gel with that of NaF varnish in preventing carious lesions in preschool children when applied at half-yearly intervals over a 24-month period.

Methods / Design: This non-inferiority randomised clinical trial will recruit 1500 3- to 4-year-old children to receive either SDF gel or NaF varnish every 6 months. The primary outcome is SDF gel will be more effective than NaF varnish in preventing ECC when both are applied at half-yearly intervals at the 24-month follow-up. The same examiner will conduct all examinations at the kindergartens over 24 months. The examiner, the children, and the children's parents will be blinded to treatments. The parents will be surveyed on their child's oral health-related behaviours and socioeconomic background to allow adjustment for effect modification.

Discussion: If the result is as anticipated, clinicians can use SDF gel instead of NaF varnish to prevent ECC. As SDF gel is cost-effective, simple, non-invasive, and non-aerosol generating, it can be widely recommended for prevent early childhood caries. This study will help change the standard of preventive care. If SDF gel is adopted in Hong Kong, it could prevent kindergarten children from developing ECC, thus significantly reducing the burden of ECC among children and the related stress on their families.

• Study Type: Interventional
• Enrollment (Estimated): 1500
• Phase: Phase 2

Contacts and Locations

Study Locations

• China
  • Hong Kong, China
    • The University of Hong Kong

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• generally healthy, with parental consents

Exclusion Criteria:

• uncooperative and difficult to manage, have major systemic diseases such as porphyria, or are on long-term medication such as anti-epileptic drugs.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Silver diamine fluoride gel; 38% silver diamine fluoride gel	Drug: Silver diamine fluoride gel; Application of 38% SDF gel every 6 months over 24 months; Other Names: SDF gel
Active Comparator: Sodium Fluoride varnish; 5% Sodium Fluoride varnish	Drug: Sodium Fluoride varnish; Application of 5% NaF varnish every 6 months over 24 months; Other Names: NaF varnish

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Caries prevention	The number of sound tooth surfaces that become cavitated caries per child	The follow-up oral examinations will be conducted every 6 months for 24 months totally

Collaborators and Investigators

• Sponsor: The University of Hong Kong
• Investigators: Principal Investigator: Chun Hung Chu, The University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): August 31, 2028
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: March 3, 2026
• First Submitted That Met QC Criteria: March 3, 2026
• First Posted (Actual): March 6, 2026

Study Record Updates

• Last Update Posted (Actual): March 6, 2026
• Last Update Submitted That Met QC Criteria: March 3, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Children; Prevention; Silver Diamine Fluoride; Preschool; Caries; Fluoride Varnish
• Additional Relevant MeSH Terms: Bifluorid 12
• Other Study ID Numbers: UW 24-828

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No