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AzTrials

Early Childhood CariesPhase 2/3NCT04655430

Effect of Application Time of 38% Silver Diamine Fluoride Solution on Arresting Dental Caries in Preschool Childre

A Phase 2/3 study testing 3-second SDF application, 5-second SDF application and 10-second SDF application in people with Early Childhood Caries, run by The University of Hong Kong at 1 site in Hong Kong.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

To determine the optimal application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children. Read more about this study

Who is it for?
Ages 3 to 5 yearsHealthy volunteers can take part
Conditions the study is for
Early Childhood Caries
What is being tested?
3-second SDF application, 5-second SDF application and 10-second SDF application
Could I receive a placebo?
No, everyone receives an active treatment
How many people
665 participants
Where
1 siteHong Kong
Study dates
1 Oct 2021to 31 Jul 2022
Phase
Phase 2/3
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 3 to 5 years
  • All sexes
  • Healthy volunteers accepted
  • Child

Who may be able to join

  • 3-5 year old children attending the first to the third year of kindergarten; (b) free from any systemic conditions and generally healthy; (c) parents sign informed consent (d) having at least 1 tooth with cavitated dentine carious lesion.

Who cannot join

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

Trial locations and contacts

1 site in 1 country.

Hong Kong1 site

  • Local kindergartens

    Hong Kong

Other trials in Hong Kong

About this study

Official title: Effect of Application Time of 38% Silver Diamine Fluoride Solution on Arresting Dental Caries in Preschool Children: a Randomized Double Blinded Controlled Trial

To determine the optimal application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.

Read the detailed description

Methods: The randomized double blinded clinical trial will recruit 665 healthy kindergarten children aged 3-5 years old with caries and with parental consent. The sample size is sufficient for the appropriate statistical analyses. The children will receive 0.004 mL 38% SDF (typical amount applied per manufacturer's instructions) to treat each caries lesion. The carious teeth were block-randomized into 9 groups with SDF application times of 3, 5, 10, 15, 30, 45, 60, 120, and 180 seconds. The children will be followed up for 6-months in their kindergartens. Clinical examinations after 6-months will be conducted to assess whether the caries is arrested and surface color using a Pantone-based chart. Information on confounding factors, such as oral hygiene habits and the use of other fluoride agents, will be collected through a parental questionnaire at the baseline and 6-months follow-up. The examiner, the children and the children's parents will be blind to the treatment allocation. The analysis will determine the significance of differences between the means of arrested caries at the various follow-ups; and Cochran-Armitage test will be used to evaluate the exposure (SDF-application time) to response relationship.

Significance: This study will help determine the optimal application time in SDF treatment. The study provides an evidence-based protocol for the use of silver diamine fluoride to arrest tooth decay in primary teeth of young children.

Being tested
3-second SDF application, 5-second SDF application, 10-second SDF application, 15-second SDF application, 30-second SDF application
Keywords
silver diamine fluoride, application time, preschool children, early childhood caries

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 3-second SDF applicationOther

    Dosage: 3-second 38% SDF solution application

  • 5-second SDF applicationOther

    Dosage: 5-second 38% SDF solution application

  • 10-second SDF applicationOther

    Dosage: 10-second 38% SDF solution application

  • 15-second SDF applicationOther

    Dosage: 15-second 38% SDF solution application

  • 30-second SDF applicationOther

    Dosage: 30-second 38% SDF solution application

  • 45-second SDF applicationOther

    Dosage: 45-second 38% SDF solution application

  • 60-second SDF applicationOther

    Dosage: 60-second 38% SDF solution application

  • 120-second SDF applicationOther

    Dosage: 120-second 38% SDF solution application

  • 180-second SDF applicationOther

    Dosage: 180-second 38% SDF solution application

Study groups in NCT04655430
Study groupRoleWhat they receive
3-second SDF applicationExperimental3-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 3-second SDF application
5-second SDF applicationExperimental5-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 5-second SDF application
10-second SDF applicationExperimental10-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 10-second SDF application
15-second SDF applicationExperimental15-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 15-second SDF application
30-second SDF applicationExperimental30-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 30-second SDF application
45-second SDF applicationExperimental45-second application time of silver diamine fluoride (38% SDF) in arresting tooth decay (dental caries) in the primary teeth of preschool children.
Receives: Other: 45-second SDF application
60-second SDF applicationExperimental60-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 60-second SDF application
120-second SDF applicationExperimental120-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 120-second SDF application
180-second application timeExperimental180-second application time of silver diamine fluoride (38% SDF) in arresting dental caries in the primary teeth of preschool children.
Receives: Other: 180-second SDF application

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Clinical Status of Caries Arrest (Surface Hardness)

    Surface hardness is independently evaluated by a calibrated examiner using a dental probe with a standard tactile technique. Lesions are classified as "Hard" (indicating successful caries arrest) or "Soft" (indicating an active, non-arrested lesion).

    Measured: From enrollment to the end of treatment at 6 months

  2. dmft index

    The tooth discoloration, tooth status (decayed, missing or filled teeth teeth (dmft) index) and tooth mobility

    Measured: at 6-months follow-up

  3. The visible plaque index (VPI).

    Two areas (buccal and lingual) of each of the six index teeth (55/51/63/71/75/83) will be examined and recorded (presence/absence) without visible plaque.

    Measured: at 6-months follow-up

Secondary outcomes (1)

  1. Clinical Presentation of Lesion Coloration

    This assessment evaluates the visual appearance of each dental caries lesion using a standardized Pantone-based coloration chart which including yellow, light brown, dark brown and black.

    Measured: From enrollment to the end of treatment at 6 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted7 Dec 2020
  2. Study start1 Oct 2021
  3. Primary completion31 Jul 2022
  4. Study completion31 Jul 2022

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2/3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
665 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04655430
Sponsor's protocol ID
HKU20201127
Status last verified
Oct 2023
First submitted
30 Nov 2020
Last updated
15 Jun 2026
Results posted
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Yan IG, Zheng FM, Sun IG, Lo ECM, Duangthip D, Chu CH. A Randomized Controlled Trial of Silver Diamine Fluoride Application Time. J Dent Res. 2025 Dec;104(13):1453-1461. doi: 10.1177/00220345251345801. Epub 2025 Jun 29.

    PubMed 40583169

  • Yan IG, Zheng FM, Gao SS, Duangthip D, Lo ECM, Chu CH. Effect of application time of 38% silver diamine fluoride solution on arresting early childhood caries in preschool children: a randomised double-blinded controlled trial protocol. Trials. 2022 Mar 15;23(1):215. doi: 10.1186/s13063-022-06130-1.

    PubMed 35292085

Questions about this trial

What is this clinical trial studying?

A Phase 2/3 study testing 3-second SDF application, 5-second SDF application and 10-second SDF application in people with Early Childhood Caries, run by The University of Hong Kong at 1 site in Hong Kong.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 15 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Hong Kong. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Clinical Status of Caries Arrest (Surface Hardness) (time frame: From enrollment to the end of treatment at 6 months). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04655430, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Jun 2026.

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