Periodontal diseases and dental caries are among the most common oral diseases and the main reason for tooth loss. Prevention of these diseases is of high priority considering the high cost of its treatment. Dental plaque is the main factor in the development and progression of periodontal diseases and dental caries. Daily mechanical plaque removal by toothbrushing is an important addition to professional plaque removal techniques and a key strategy for oral health maintenance. However, toothbrushes alone are unable to adequately penetrate interdental areas where periodontal diseases and dental caries are most commonly found. Therefore, interdental cleaning aids, namely dental floss and interdental brushes, have been recommended in addition to regular toothbrushing. In order to assess the efficacy and safety of flossing and interdental brushing, in addition to toothbrushing, in the prevention and control of periodontal diseases and dental caries in adults two Cochrane systematic reviews have been conducted. The methodology used in both reviews is based on the explicit methods described in the Cochrane Handbook for Systematic Reviews of Interventions. According to the predefined inclusion criteria, only RCTs were included in the reviews. 12 studie were included in the Flossing review with 582 participants in the toothbrushing and flossing group and 501 participants in the toothbrushing only control groups. There is evidence of the efficiency of flossing, in addition to toothbrushing, in the reduction of gingivitis at one, three and six months. However, only weak and unreliable evidence of its benefit in the reduction of dental plaque after one and three months have been found. Seven studies were included in the Interdental brushing review with 197 participants enrolled in the interdental brushing plus toothbrushing study arms and 195 participants in the flossing plus toothbrushing control groups. The use of interdental brushes in addition to toothbrushing has proved to be more beneficial than toothbrushing alone, in the reduction of gingivitis after one month. When compared to dental floss, interdental brushes are more efficient in reducing gingivitis after one month. As for dental plaque, there was insufficient evidence to claim a benefit for either of the interdental aids. Due to inconsistency in reporting, data analysis concerning adverse effects was not possible. No studies examining the efficiency of dental floss and interdental brushes in the prevention of caries in adults have been found.