To be eligible for the review, studies needed to be randomised controlled clinical trials or controlled clinical trials. Eligible participants were 18 years of age or older and in good general health. Dental flossing and manual toothbrushing had to be compared with a control group using manual toothbrushing only. Interproximal sites needed to be measured and patients should have no orthodontic appliances. Studies lasting four weeks or more were eligible. Only trials written in English were accepted.
There was considerable variation in the study design, characteristics and outcome variables of the included trials. The mean age of the participants was approximately 28 years, ranging from 18 to 70 years. All trials were randomised (four had a crossover design and seven a parallel design) and lasted from four weeks to six months.
A variety of outcome measures were used to assess plaque, gingivitis and bleeding on probing. One trial compared two different kinds of dental floss, six trials used waxed floss and four trials used unwaxed floss. Seven of the trials reported industry funding.
Trials were selected by more than one reviewer and any disagreements between reviewers were resolved by discussion.