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Limited evidence suggests fluoride varnish applied twice yearly is effective for caries prevention in children

Arthur Jeske DMD, PhD; James Zahrowski DMD, MS, PharmD .


Systematic Review Conclusion

This systematic review identified seven controlled trials which met clearly stated inclusion criteria. The authors concluded that fluoride varnish, applied twice yearly, effectively reduces the incidence of caries among high-risk children and adolescents.

Critical Summary Assessment

A qualitative systematic review of limited evidence consisting of seven controlled studies, five of which were randomized but with questionable blinding, finds fluoride varnish applied twice yearly decreases caries incidence in both high-risk children and adolescents.

Evidence Quality Rating

Limited Evidence

Structured Abstract

Clinical Questions:

In high-risk children and adolescents, does fluoride varnish application, as compared with no treatment, effectively prevent caries?

Review Methods:

The authors searched four electronic data bases from 2000 to 2007. To access references in identified publications, they conducted a manual search. Two independent authors identified and scored the articles. They excluded articles that did not address the clinical question. The reviewers evaluated the quality of evidence using the classification system developed by the Canadian Task Force on Preventive Health Care. Results were presented descriptively.

Main Results:

The authors identified 105 studies, of which they selected seven prospective clinical trials (4,227 subjects, mostly high-risk children and adolescents). Of the seven studies that were included, five of them reported that fluoride varnishes reduced caries in moderate- and high-risk children and adolescents. One of the strongest clinical trials (271 patients) found high-carie risk patients had fewer approximal dental lesions after fluoride varnish applied twice yearly for 3 years (0.23 +/- 0.74) vs. control (0.85 +/- 1.35) at p = 0.031.


Children and adolescents at high risk for caries would benefit from twice yearly application of fluoride varnish. Oral health programs should include other complementary caries prevention strategies, such as sealants, tooth brushing, and nutrition counseling.

Source of Funding:

Primary Health Care and Public Health Directorate, First Nations and Inuit Health Branch, Health Canada.


Importance and Context:

Fluoride treatments have shown to substantially reduce tooth decay in both primary and permanent teeth.(1) Fluoride varnishes provide longer fluoride contact with enamel and offer the advantages of less fluoride ingestion and ease of application. Single-dose fluoride varnish packets have been reported to deliver the most uniform fluoride concentration when stirred vigorously prior to application. Fluoride varnish, although efficacious for caries prevention, has not been found superior to gel applications. Evaluation of current research is needed to assess efficacy of fluoride varnish treatments.

Strengths and Weaknesses of the Systematic Review:

This systematic review included a comprehensive search with defined inclusion and exclusion criteria. The authors searched for English-only publications. They did not search for grey literature nor contact manufacturers. A list of excluded studies was not provided. The authors assessed the quality of the included trials. The study results could not be combined and were presented descriptively. Some of the author’s recommendations were not evaluated in the included controlled clinical trials.

Strengths and Weaknesses of the Evidence:

Two lower quality studies were of faulty design with no blinding, randomizing, or controlling outside of fluoride. One study concluded that varnish had no protective effect. Another study included the use of chlorhexidine varnish, which would make the results difficult to assess.

Implications for Dental Practice:

An expert panel of the American Dental Association concluded that, "Fluoride varnish applied every six months is effective in preventing caries."(2) Topical fluoride administration should be based on a caries risk assessment and caries risk factors such as three-year history of caries, poor oral hygiene, cariogenic diet, presence of cariogenic bacteria, exposed root surfaces, and orthodontic treatment. Fluoride varnish, when applied twice yearly, is efficacious for preventing caries in caries-prone children and adolescents with high carie patients possibly benefiting from an application every three months.(2) Application of fluoride varnish in addition to a comprehensive oral health care program including sealants, oral hygiene instruction, and nutritional counseling may be beneficial. 1. Marinho VCC, Higgins JPT, Logan S, Sheiham A. Topical fluoride (toothpastes, mouthrinses, gels or varnishes) for preventing dental caries in children and adolescents.Cochrane Database of Systematic Reviews 2003,Issue 4. Art. No.: CD002782. DOI: 10.1002/14651858.CD002782. 2. American Dental Association Council on Scientific Affairs. Professionally applied topical fluoride: evidence based clinical recommendations. JADA 2006; 137(8):1151-9.

Critical Summary Publication Date:


These summaries are not intended to, and do not, express, imply, or summarize standards of care, but rather provide a concise reference for dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. American Dental Association © 2019