Study designs of evaluations included in the review
Randomised controlled trials and controlled trials using a parallel-group or split-mouth design were eligible for inclusion. The duration of the studies ranged from 0.75 to 3 years.
Specific interventions included in the review
Studies comparing CHX varnish with placebo or no anti-caries treatment were eligible for inclusion. Just under half of the included studies compared treatment with placebo, while most of the remaining studies used no treatment controls; other controls used were cleaning and neutral gel. The types of CHX varnish included Cervitec, EC40 and Chlorzoin. Application regimens varied and were described in the data tables. The duration of follow-up from last application varied between 3 and 39 months. Treatments were applied to the occlusal surface of first and/or second permanent molars; permanent teeth with orthodontic appliances; the fissure and pits of first permanent teeth; or all permanent teeth.
Participants included in the review
Studies including children, young adults and adults were eligible for inclusion. Studies on primary teeth, root caries and older adults (over 25 years old) were excluded. The included studies were of children (age range: 5 to 8 years), young adults (age range: 11 to 14 years), or both; none of the studies included adults.
Outcomes assessed in the review
Studies had to measure the caries-inhibiting effect using clinical and/or radiographic methods to be eligible for inclusion. The primary outcome used in the review was prevented fraction (PF): described as the increase in caries in the control group minus the increase in caries in the intervention group, divided by the increase in caries in the control group. The methods used to calculate PF were provided. Studies that did not provide sufficient information (either within the paper or as extra information from the authors) to calculate the PF were excluded. The outcome measures used in the included studies varied and included decayed, missing or filled surfaces or teeth. The majority of the studies recorded dentine caries alone or in addition to enamel caries.
How were decisions on the relevance of primary studies made?
Two reviewers assessed the relevance of studies.