Tooth decay is a health problem worldwide, affecting the vast majority of adults and children. Levels of tooth decay vary between and within countries, but children in lower socioeconomic groups (measured by income, education and employment) tend to have more tooth decay. Untreated tooth decay can cause progressive destruction of the tops of teeth (crowns), often accompanied by severe pain. Repair and replacement of decayed teeth is costly in terms of time and money and is a major drain on the resources of healthcare systems.
Preventing tooth decay in children and adolescents is regarded as a priority for dental services and is considered more cost-effective than treatment. Use of fluoride, a mineral that prevents tooth decay, is widespread. As well as occurring naturally, fluoride is added to the water supply in some areas, and is used in most toothpastes and in other products that are available to varying degrees worldwide. As an extra preventive measure, fluoride can be applied directly to teeth as mouthrinses, lozenges, varnishes and gels.
Fluoride mouthrinse has frequently been used under supervision in school-based programmes to prevent tooth decay. Supervised (depending on the age of the child) or unsupervised fluoride mouthrinse needs to be used regularly to have an effect. Recommended procedure involves rinsing the mouth one to two minutes per day with a less concentrated solution containing fluoride, or once a week or once every two weeks with a more concentrated solution. Because of the risk of swallowing too much fluoride, fluoride mouthrinses are not recommended for children younger than six years of age.
This review updates the Cochrane review of fluoride mouthrinses for preventing tooth decay in children and adolescents that was first published in 2003.
What was the research?
A systematic review of the evidence to find out the effectiveness and safety of the use of fluoride mouthrinse for preventing tooth decay (dental caries) in children and adolescents. The mouthrinse was compared with placebo (a mouthrinse without the active ingredient fluoride) or no treatment.
Who conducted the research?
The research was conducted by a team led by Valeria CC Marinho, from Barts and The London School of Medicine and Dentistry, Queen Mary University of London, on behalf of Cochrane Oral Health. Lee Yee Chong, Helen V Worthington and Tanya Walsh were also on the team.
What evidence was included in the review?
37 randomised controlled trials (RCTs) were included, children (aged six to 14 years) were treated either with fluoride mouthrinse or placebo (a mouthrinse with no active ingredient) or received no treatment. All of these studies assessed supervised use of fluoride mouthrinse in school settings, with two studies also including home use. For almost all children, the fluoride rinse they received was a sodium fluoride (NaF) solution, given at two main strengths and rinsing frequencies – 230 parts per million of fluoride (ppm F) daily, or a higher concentration of 900 ppm F weekly or fortnightly. The trials lasted from two to three years and took place in several countries.
What did the evidence say?
This review update confirmed that supervised regular use of fluoride mouthrinse can reduce tooth decay in children and adolescents. Combined results of 35 trials showed that, on average, there is a 27% reduction in decayed, missing and filled tooth surfaces in permanent teeth with fluoride mouthrinse compared with placebo or no mouthrinse. This benefit is likely to be present even if children use fluoride toothpaste or live in water-fluoridated areas. Combined results of 13 trials found an average 23% reduction in decayed, missing and filled teeth (rather than tooth surfaces) in permanent teeth with fluoride mouthrinse compared with placebo or no mouthrinse. No trials have looked at the effect of fluoride rinse on baby teeth. We found little information about unwanted side effects or about how well children were able to cope with the use of mouthrinses.
How good was the evidence?
Available evidence for permanent teeth is of moderate quality. This means we are moderately confident in the size of the effect. Very little evidence is available to assess adverse effects.
What are the implications for dentists and the general public?
The evidence seems applicable to current clinical practice. Although the evidence base for fluoride mouthrinse comes mainly from studies conducted when fluoridated toothpaste was not widely available in the 1960s and 1970s, the eight trials from the 1980s and 1990s show no evidence of smaller treatment effects. Supervised regular use of fluoride mouthrinse by children and adolescents is associated with a large reduction in caries increment in permanent teeth.
What should researchers look at in the future?
A large number of trials was identified, but the reporting of the trials included in this review is relatively poor, with many lacking important methodological details. This is likely due in part to the fact that most are relatively old. Many characteristics considered crucial for excluding bias, such as clearly stated randomisation and allocation concealment, have been more emphasised only in recent years, after most of the mouthrinse trials were reported. However, given the clarity of study results, additional randomised comparisons of fluoride mouthrinse and placebo alone would be difficult to justify. Head-to-head comparisons of fluoride rinses and other preventive strategies, and of different fluoride rinse application features, may provide more useful information.
It is important that future trials include assessment of other relevant outcomes such as potential adverse effects and those related to acceptability of treatment. Planning and conducting an economic analysis alongside the clinical trial could be considered. In addition, evaluation of possible differences in effect associated with fluoride rinse application features, such as frequency/concentration of application, should be based on trials that directly compare such features. Future trials should be well-designed RCTs, reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org).
Regular use of fluoride mouthrinse under supervision results in a large reduction in tooth decay in children’s permanent teeth. Little information was found about potential adverse effects and acceptability.
Marinho VCC, Chong LY, Worthington HV, Walsh T. Fluoride mouthrinses for preventing dental caries in children and adolescents. Cochrane Database of Systematic Reviews 2003 , Issue 3 . Art. No.: CD002284. DOI: 10.1002/14651858.CD002284
Update: see what 15 year-old Liv Chapman makes of the evidence in Evidently Cochrane’s latest post.
This blog post is based on the review’s plain language summary and was compiled at the Cochrane Oral Health Editorial Base by Anne Littlewood