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Clinical Insights: Water Flossing is Key to Maintaining Oral Health

Safe and effective, water flossing offers myriad oral health benefits.

Dental professionals know that interdental cleaning is a critical component of optimal oral health. Traditionally, dental floss is the first tool recommended for interproximal cleaning; however, it has largely escaped the scientific rigor required of most products. Over the past decade, this has shifted, and reviews of interdental aids—including water flossing—have produced results that disrupt traditional thinking. 

In March 2020, a clinical practice guideline on treating periodontitis concluded: “We do not suggest flossing as the first choice for interdental cleaning in periodontal maintenance patients.”1 The investigators found that interdental brushes and water flossers reduce inflammation and are preferred by patients.1 This supports a 2018 meta-analysis that demonstrated interdental brushes and water flossers ranked high for reducing gingival bleeding, while toothpicks and dental floss ranked last.2 A 2019 review supports the effectiveness of interdental brushes and water flossers for reducing inflammation as well as patient preference for implant maintenance over dental floss.3 While many dental professionals are comfortable pivoting to interdental brushes, others find accepting the efficacy of the water flosser more difficult. Roadblocks include the following misnomers about water flossers: they cannot remove plaque, they are only adjuncts to string floss, they make pockets deeper, and they increase the risk of bacteremia. The evidence disproves these ideas. 

waterpikWhen it comes to plaque removal, most of us were taught that plain water is not effective. With drinking or swishing, this is true. However, with water flossing, there is a unique combination of pulsation and pressure that creates shear hydraulic forces that remove up to 99.9% of plaque biofilm.4 At the University of Southern California Center for Dental Biofilm, investigators extracted severely periodontally involved teeth that were coated in heavy biofilm. The teeth were then treated with 3 seconds of water flossing on a medium pressure setting. Evaluated via a scanning electron microscope, the researchers were able to see the shear hydraulic forces produced by water flossing and the resulting removal of plaque biofilm.4

Several studies have compared water flossing to string floss5–9 and interdental brushes.10,11 In each study, water flossing improved oral health significantly better than string floss or interdental brushes. Barnes et al5 demonstrated that the water flosser was superior to string floss when paired with either a manual or power brush, thus, concluding it was the water flosser that provided the additional oral health benefits. Water flossing is also safe for tissue,9,12 and any bacteremia produced by water flossing is similar to string flossing.12 A study tested a manual toothbrush and water flosser at various pressure settings and compared it to manual brushing and flossing and manual brushing alone. For the first 2 weeks, subjects gradually increased the pressure setting from #1 to #8. For weeks 3 and 4, water flossing was done at setting #9, and in weeks 5 and 6 at setting #10. At the conclusion of the study, subjects in the water flossing group showed no negative impact on the gingival tissue or epithelial attachment. Participants who used the water flosser showed more significant improvements in pocket depth and clinical attachment over the other two groups.9 This supports a review of the literature that found no detrimental effects from water flossing to the attachment, junctional epithelium, or pocket depth, nor did water flossing increase subgingival pathogens.12 

Water flossing is safe and effective. The Waterpik® brand of water flossers is supported by more than 80 published scientific studies. This depth of scientific support has earned the Waterpik® Water Flosser and Waterpik® Sonic-Fusion the American Dental Association Seal of Acceptance for safety and efficacy.

Water pik, inc.



  1. Sanz M, Herrer D, Kebschull M, et al. Treatment of stage I-III periodontitis—the EFP S3 level clinical practice guideline. J Clin Periodontol. 2020;47(Suppl 22):4–60.
  2. Kotsakis GA, Lian Q, Ioannou AL, et al. A network meta-analysis of interproximal oral hygiene methods in the reduction of clinical indices of inflammation. J Periodontol. 2018;89:558–570. 
  3. Ng E, Lim LP. An overview of different interdental cleaning aids and their effectiveness. Dent J. 2019:7:56. 
  4. Gorur A, Lyle DM, Schaudinn C. Biofilm removal with a dental water jet. Compend Contin Educ Dent. 2009;30(Special1):1–6. 
  5. Barnes CM, Russell CM, Reinhardt RA, et al. Comparison of irrigation to floss as an adjunct to toothbrushing: effect on bleeding, gingivitis, and supragingival plaque. J Clin Dent. 2005;16:71–77. 
  6. Magnuson B, Harsono M, Stark PC, et al. Comparison of the effect of two interdental cleaning devices around implants on the reduction of bleeding: a 30-day randomized clinical trial. Compend Contin Educ Dent. 2013;34(Special 8):2–7. 
  7. Rosema NAM, Hennequin-Hoenderdos NL, Berchier CE, et al. The effect of different interdental cleaning devices on gingival bleeding. J Int Acad Periodontol. 2011;13:2–10
  8. Sharma NC, Lyle DM, Qaquish JG, et al. Effect of a dental water jet with orthodontic tip on plaque and bleeding in adolescent patients with fixed orthodontic appliances. Am J Orthod Dentofacial Orthop. 2008;133:565–571. 
  9. Goyal CR, Qaqish JG, Schuller R, et al. Evaluation of the safety of a water flosser on gingival and epithelial tissue at different pressure settings. Compend Cont Dent Educ. 2018;39(Suppl 2):8–13. 
  10. Goyal CR, Lyle DM, Qaqish JG et al. Comparison of water flosser and interdental brush on reduction of gingival bleeding and plaque: a randomized controlled pilot study. J Clin Dent. 2016;27:61–65. 
  11. Lyle DM, Goyal CR, Qaqish JG, et al. Comparison of water flosser and interdental brush on plaque removal: A single-use pilot study. J Clin Dent. 2016;27:23–26. 
  12. Jolkovsky DL, Lyle DM. Safety of a water flosser: a literature review. Compend Contin Educ Dent. 2015; 36:146–149.

From Dimensions of Dental Hygiene. September 2021;19(9):25.

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