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

Plain English Summary

Background and study aims
Sjögren's syndrome is an autoimmune disorder where the body’s immune system attacks glands that secrete fluid, such as the salivary glands. This leads to a reduced production of saliva, making patients more prone to tooth decay (caries). Fluoride varnish is commonly applied onto their teeth for caries prevention. The aim of this study is to investigate the effectiveness of fluoride varnish in caries prevention in this group of patients.

Who can participate?
Sjögren’s syndrome patients aged 18 or over with eight or more natural teeth.

What does the study involve?
Participants are randomly allocated to one of two groups. Participants in one group have their teeth treated with fluoride varnish quarterly and participants in the other group have their teeth treated with a placebo (dummy) gel quarterly. Their teeth are assessed for caries at the start of the study and after 12 and 24 months, along with the amount of Candida (a fungus) and lactobacilli (bacteria) in the mouth.

What are the possible benefits and risks of participating
Participants are provided with free-of-charge dental examinations, oral hygiene instructions, dental treatment (restorations and prostheses), and periodontal (gum) treatment if needed. There is a temporary effect of fluoride varnish as it leaves a yellow film on the teeth for several hours after application unless it is removed by brushing.

Where is the study run from?
Prince Philip Dental Hospital, Faculty of Dentistry, The University of Hong Kong (Hong Kong)

When is the study starting and how long is it expected to run for?
January 2009 to October 2013

Who is funding the study
Research Grants Council of Hong Kong (Hong Kong)

Who is the main contact?
Dr Katherine Leung

Trial website

Contact information



Primary contact

Dr Katherine Leung


Contact details

Prince Philip Dental Hospital
34 Hospital Road
Sai Ying Pun
Hong Kong
Hong Kong

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A randomized, double-blind, placebo-controlled clinical trial of fluoride varnish in preventing dental caries of Sjögren’s syndrome patients


Study hypothesis

Quarterly applied fluoride varnish can prevent caries development in Sjögren’s syndrome patients.

Ethics approval

Institutional Review Boards of the University of Hong Kong/Hospital Authority Hong Kong West and Kowloon Central and East Clusters, 23/04/2008, refs: UW 08-167 and KC/KE-10-0014/ER-2

Study design

Randomized double-blind placebo-controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

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


Caries development in Sjögren’s syndrome patients


Sjögren’s syndrome patients were randomly assigned to receive either professionally applied fluoride varnish or placebo gel quarterly. Development and arrest of caries at the coronal and root surfaces were recorded at 12 months and 24 months and compared to that of the baseline. Effect of fluoride varnish on oral Candida and lactobacilli colonization was explored by comparing baseline oral microbiological assessments to data obtained at 12 months and 24 months.

Intervention type



Drug names

Primary outcome measures

Caries at the coronal and root surface evaluated using the International Caries Detection and Assessment System (ICDAS) at 12 months and 24 months

Secondary outcome measures

Counts of lactobacilli and Candida (expressed as colony forming units per milliliter (CFU/ml) in salivary samples and colony forming units per gram in dental plaque samples) evaluated at 12 months and 24 months

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Clinical diagnosis of Sjögren’s syndrome established using the American-European Consensus Group (AECG) criteria at least 6 months before the commencement of this study
2. Age 18 or above
3. Had 8 or more natural teeth present

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Severe periodontal disease (e.g., periodontal pockets were deeper than 6 mm) at two or more sextants
2. Received therapeutic irradiation to the head and neck region
3. Had concurrent systemic illness (except connective tissue disorder associated with secondary Sjögren’s syndrome)
4. Taking medication that altered salivary flow
5. Had participated in a clinical trial within 6 months before commencement of this trial

Recruitment start date


Recruitment end date



Countries of recruitment

Hong Kong

Trial participating centre

Prince Philip Dental Hospital
Faculty of Dentistry The University of Hong Kong 34 Hospital Road Sai Ying Pun
Hong Kong

Sponsor information


Research Grants Council of Hong Kong

Sponsor details

Shui On Centre
6-8 Harbour Road
Hong Kong
Hong Kong

Sponsor type

Research council



Funder type

Research council

Funder name

Research Grants Council, University Grants Committee

Alternative name(s)


Funding Body Type

private sector organisation

Funding Body Subtype



Hong Kong

Results and Publications

Publication and dissemination plan

A manuscript has been submitted to be considered for publication

Intention to publish date


Participant level data

Available on request

Results - basic reporting

Publication summary

2016 results in:

Publication citations

Additional files

Editorial Notes

23/09/2016: Publication reference added.