Condition category
Oral Health
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Children in Cambodia have a severe burden of dental caries (tooth decay) especially affecting the primary teeth. The average 6 year old Cambodian child has 9 cavitated teeth and 2.7 pulpally involved teeth. If the conventional treatment approach to address these problems (e.g. “drilling and filling” and extractions) was implemented, the costs would be more than the national health budget for Cambodia, and the whole dental workforce of Cambodia could still not provide all the treatment needed. In the case of the Healthy Kids Cambodia Strategy, Silver Fluoride treatments have been used since 2014 and are viewed as the best first step to slowing down or arrest the dental caries process among a population where the disease is ubiquitously severe. The main disadvantage of treatment with Sliver Fluoride solutions is that the cavitated carious lesions become a dark black colour which could potentially be stigmatising or unacceptable to children and their families. For that reason, it is important to explore ways in which we can achieve the most aesthetically favourable outcome. The addition of potassium iodide solution to the clinical procedure has been shown to improve aesthetic outcomes in other settings and so the aim of this study is to confirm whether or not this type of treatment can achieve the same results among Cambodian children.

Who can participate?
Children who are 7- to 10-years old, with one or more active carious lesions (cavities) in primary teeth not involving the pulp, and attending schools that are targeted to begin the Healthy Kids Cambodia Project during the 2018-2019 academic year

What does the study involve?
Participants are randomly allocated at the school level to one of four different Silver Fluoride treatments: Rivastar version 1 with and without potassium iodide (step 2), and Rivastar version 2 with and without step 2. This treatment is provided to children at the start of the study and at 6-month follow-up. The solutions are painted onto dry teeth using a small brush.

What are the possible benefits and risks of participating?
The benefits of participating are that cavities will become stable and children will experience a reduction in symptoms as a result of dental caries. The risks are that they may not like the aesthetic appearance of cavities that become a darker colour.

Where is the study run from?
University of Puthisastra, Phnom Penh (Cambodia)

When is the study starting and how long is it expected to run for?
October 2018 to March 2020

Who is funding the study?
SDI Limited

Who is the main contact?
Dr Bathsheba Turton

Trial website

Contact information



Primary contact

Dr Bathsheba Turton


Contact details

Street 180-184
Sangkat Boeung Raing
Khan Daun Penh
Phnom Penh
+855 (0)10316672

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Arrest of caries using different silver fluoride solutions in the Healthy Kids Cambodia project


Study hypothesis

1. Rivastar version 1 and version 2 have the same caries arrest rate
2. The addition of 'step 2' with potassium iodide will improve the aesthetic outcome

Ethics approval

National Ethics Committee for Health Research, National Institute of Public Health, #80, Samdach Penh Nouth Blvd, Sangkat Boeungkok2, Khan Toul Kork, Phnom Penh, Tel: +855 (0)12842442 / +855 (0)12528789 / +855 (0)12203382, Email: /, ref: 307NECHR

Study design

Four-arm parallel-design randomized controlled trial

Primary study design


Secondary study design

Cluster randomised trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


Dental caries


This is a four-armed, parallel-design randomized controlled trial that will follow the recommendations for Interventional Trials (SPIRIT) 2013 Statement. The study will include those children from four schools who were scheduled to join the HKC strategy in the 2019-2020 academic year, thus facilitating the early access to HKC interventions. Children will be randomized at school level for allocation into the four treatment groups. Those who do not meet the inclusion criteria will receive routine HKC treatment and management.

All groups will receive treatment at both baseline and follow-up. At each treatment, Group 1 is the Rivastar 2-step group and children will receive 0.1 ml of Rivastar solution together with 0.1 ml step 2 (potassium iodide solution) . Group 2 will receive the Rivastar solution without the 'step 2'. Group 3 will receive the 'Rivastar version 2' solution (0.1 ml) and the 'step 2' solution (0.1 ml) at each treatment. Group 4 will receive the 'Rivastar version 2' solution only.

Updated 25/02/2019 to correct the doses:
All groups will receive treatment at both baseline and follow-up. At each treatment, Group 1 is the Rivastar 2-step group and children will receive 0.05 ml of Rivastar solution together with 0.1 ml step 2 (potassium iodide solution). Group 2 will receive the Rivastar solution without the 'step 2'. Group 3 will receive the 'Rivastar version 2' solution (0.05 ml) and the 'step 2' solution (0.1 ml) at each treatment. Group 4 will receive the 'Rivastar version 2' solution only.

Data will be collected at recruitment, during the baseline examination and at each AgF Application and data will include both a questionnaire as well as intraoral examinations. Each child will be assigned a unique identifier at baseline though the Healthy Kids Cambodia database system and that identifier will be used to track the child throughout the trial. Data analysis will be performed on a de-identified dataset only and in that way, the identity of participants will be protected.

Intervention type



Drug names

Primary outcome measure

Stability of carious lesions defined based on (a) lesion progression (b) lesion colour and (c) lesion texture at 6 months and 12 months. Method for measurement of outcomes will be through clinical observation of the size of the carious lesion using the International Caries Detection and Assessment System version II (ICDAS-II) as well as observation of the color of the carious lesion and the hardness of the carious lesion.

Secondary outcome measures

The presence or absence of oral symptoms as defined by the presence or absence of an ‘impact’ on oral symptoms using the oral symptoms domain of the previously validated Child Perceptions Questionnaire at 6 months and 12 months

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Children with one or more active carious lesions in primary tooth not involving the pulp
2. Participants who will begin the Healthy Kids Cambodia project in Takeo and Kampot provinces during the 2018-2019 academic year
3. Children in Grade 5 or below (age range 6-to 11 years of age)

Participant type


Age group




Target number of participants

600 participants; 150 participants per cluster

Total final enrolment


Participant exclusion criteria

1. Children who are unable to provide adequate contact details/alternative contacts for reliable follow-up
2. Grade 6 and above children
3. Children belonging to families who have a plan to shift out of the region in the 12 months following recruitment
4. Children for whom their parents refuse consent at any stage during the study
5. Children who refuse assent at any stage during the study
6. Children with no teeth that are eligible to be included in the trial

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Faculty of Dentistry, University of Puthisastra
#55, street 180
Phnom Penh

Sponsor information


SDI Limited

Sponsor details

3-15 Brunsdon St. Bayswater

Sponsor type




Funder type


Funder name

SDI Limited

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

6-month and 12-month results will be published

IPD sharing statement
The datasets generated during and/or analysed during the current study are/will be available upon request from Bathsheba Turton ( Data will be available until 2025 for inclusion into meta-analysis. Consent for participants was obtained for use of data for research purposes only and de-identified data (only) could potentially be provided under reasonable request. The principal investigator retains full academic freedom for the use of the data.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

21/06/2019: Total final enrolment number added, intention to publish date changed from 31/12/2019 to 31/3/2021. 25/02/2019: The interventions field was updated.