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Nov/Dec 2011
Volume 32, Issue 9

Use of a Water Flosser For Interdental Cleaning

Deborah M. Lyle, RDH, MS


Interdental cleaning is an important part of a patient’s personal oral care regimen. Water flossers, also known as oral irrigators or dental water jets, can play a vital, effective role in interdental hygiene. Evidence has shown a significant reduction in plaque biofilm from tooth surfaces and the reduction of subgingival pathogenic bacteria from pockets as deep as 6 mm with the use of water flossing. In addition, water flossers have been shown to reduce gingivitis, bleeding, probing pocket depth, host inflammatory mediators, and calculus. Educating patients on the use of a water flosser as part of their oral hygiene routine can be a valuable tool in maintaining oral health.

There are several goals to personal oral hygiene, including preventing oral infection and disease, maintaining the results achieved from debridement and other oral hygiene procedures, protecting the esthetic investment, and limiting the inflammatory burden both orally and systemically. This can be a difficult task, especially for individuals who are at increased risk for periodontal disease.

Interdental cleaning is a key step in a personal oral care regimen. Traditionally, personal oral hygiene starts with brushing and flossing. A considerable amount of chairside instruction is devoted to teaching flossing, yet the success of changing behavior is minimal at best. Patients state a variety of reasons for not flossing, including it is difficult to do, and when given a choice they readily choose other interdental devices such as brushes and floss holders over floss.1-3

Floss is considered the “gold standard” of interdental care. However, research challenges this standing. A 2008 systematic review assessed the adjunctive effect of toothbrushing and flossing compared to toothbrushing alone.4 Of the more than 1,300 studies reviewed 11 publications met the criteria: randomized controlled trial (RCT); ≥ 18 years of age; duration of ≥ 4 weeks; measurements of interproximal sites for gingivitis, plaque, and bleeding; and no orthodontic appliances. Of the 11 studies included, two demonstrated a significant difference between groups in favor of the floss for plaque removal, no studies demonstrated a difference between the groups for gingivitis score, and only one study showed a significant difference for bleeding for the floss group.

A benefit of flossing that has been widely accepted is the reduction of interproximal caries. Hujoel and colleagues assess the benefits of flossing on interdental caries in a systematic review.5 Of the 144 studies identified, six were included in the analysis with a total of 808 children aged 4 to 13 and followed for 1.7 to 3 years. No studies with adult subjects where flossing was supervised, unsupervised, or professionally administered were identified. The analysis found that in one study professional flossing in first graders on school days reduced caries risk by 40%. This was mostly in primary teeth and it is assumed that these children had poor oral hygiene and minimal exposure to fluoride. In contrast, when adolescents performed self-flossing on school days under supervision there was no evidence of a benefit. Infrequent professional flossing every 3 months did not show a reduction in caries risk. With these findings coupled with significant lack of compliance, it may be more effective for dentists to change their message from “flossing” to “interdental cleaning” and focus on patient preference and outcomes.

A water flosser, also known as an oral irrigator or dental water jet, has been around for almost 50 years. Use of this type of product by consumers or recommendations by dental professionals has waxed and waned over the decades. This has been primarily related to anecdotal comments and articles stating water flossers do not remove plaque biofilm or cause bacteria to go deeper into the pocket. This, however, has never been a valid argument as evidence has shown a significant reduction in plaque biofilm from tooth surfaces (Figure 1 and Figure 2) as well as the reduction of subgingival pathogenic bacteria from pockets as deep as 6 mm with the use of a water flosser.6,7 In addition, a water flosser has been shown to reduce gingivitis, bleeding, probing pocket depth, host inflammatory mediators, and calculus.8-14

Water Flosser Vs. Dental Floss

Three clinical trials have been conducted that evaluated the impact of brushing and water flossing compared to brushing and flossing (Table 1). In 2005, Barnes et al compared manual or power brushing plus a water flosser with a classic jet tip to manual brushing and flossing.10 Results demonstrated, regardless of toothbrush used, the addition of a water flosser was better at reducing gingivitis and gingival bleeding compared to brushing and flossing (Figure 3). The power brush and water flosser removed significantly more plaque than the manual brush and floss. There was no difference between the manual toothbrush and water flosser and manual brush and floss for reducing plaque biofilm.

A 2008 study by Sharma et al evaluated the efficacy of a specialized orthodontic tip with adolescents in fixed appliances compared to flossing.13 The control group used a manual toothbrush only. Results showed that the water flosser was significantly better than brushing and flossing or brushing alone for reducing plaque biofilm and gingival bleeding (Figure 4). Most recently, Rosema et al compared manual brush plus a water flosser with either a standard jet tip or a new prototype tip to manual brush and flossing.14 At 4 weeks, it was evident that either tip plus manual toothbrushing were significantly better at reducing bleeding than flossing. Notably, the flossing group showed no difference statistically or numerically from baseline to 4 weeks. The 13% reduction seen at 2 weeks reverted back to baseline (0%) at 4 weeks.

How Water Flossing Works

The combination of pulsation and pressure are the key elements to the efficacy of a water flosser. Research shows that the production of 1,200 to 1,400 pulsations per minute with a pressure range of medium to high or 50 psi to 90 psi produced the best results.15 It was also shown to be safe on gingival tissue. This combination of pulsation and pressure produces a compression and decompression phase that expels debris and bacteria from subgingival and interdental areas.

Not all water flossers, oral irrigators, or dental water jets are the same. Some have pressure and pulsation specifications out of the efficacy range demonstrated in clinical studies and some are continuous-stream devices that have been shown to be less effective than pulsating models.16 Each product should be evaluated on its body of evidence, as clinical studies on one product do not support efficacy for another.

Patient Complience

Patients do not use products that are difficult or cumbersome regardless of need or clinical results. This has been shown in medical research even when it can be a life and death situation. For instance, 1 in 8 (12.5%) people who have had a heart attack stopped taking all medications by 1 month after hospital discharge.17 Eighteen percent dropped at least one drug, and another 4% discontinued two drugs. Fifty percent of people with chronic disease complied with recommendations, irrespective of disease, treatment or age.18

Compliance with oral hygiene is no different. Data shows that only 2% to 10% of the population floss regularly and effectively.19,20 It has also been reported that a substantial part of the population never floss at all.21 A recent American Dental Association (ADA) survey showed that only 32.9% reported using dental floss or other interdental cleaner once per day.22 Brushing alone cannot remove all the plaque from the tooth surface even when done correctly and thoroughly. However, the average brushing time is around 37 seconds. Good oral hygiene can deteriorate over time without reinforcement. Subjects who were given brushing and flossing instructions achieved significant improvements in plaque scores within a few weeks. These scores deteriorated to baseline within a year.23

Compliance and acceptance of a water flosser has been tested in a few studies. Hoover and Robinson noted that subjects stated they felt using a water flosser was a pleasant experience and their mouths felt cleaner.24 A 3-month study evaluated the efficacy of two water flosser devices.25 At the end of the 3 months subjects were not given any instructions regarding the water flosser use or that they would be re-examined 1 year later. On the 1-year anniversary, 21 subjects stated they were still using the water flosser daily and 29 were using it 1 to 3 times a week because “it stimulated the gums and made the teeth feel cleaner.” Sixteen subjects used it less than once a week and 49 discontinued use once they thought the study was over. Of the original 115 subjects ranging in age from 14 to 63, 74% were still using the water flosser 1 year later.

At the end of a study involving 11- to 17-year-olds with fixed orthodontic appliances, 92% of the subjects who used a water flosser stated they would continue to use the product daily or frequently compared to 58.8% for floss. A total of 94.4% stated the water flosser was very easy or somewhat easy to use compared to 52.9% for floss.13

Patients Who Benefit

The water flosser has been tested with specific patient populations and oral conditions. It has been shown to be safe and effective with implants.26 It may be especially helpful cleaning overdenture abutments and bars, or implant-supported fixed complete dentures. The pulsating water can access areas that may not be accessible by a toothbrush. Cleaning around crowns and bridges, veneers, and other restorations can be tedious and difficult. A water floss is a good choice for cleaning around the margins and abutments, under the pontic, and interdentally and subgingivally. The same is true for cleaning orthodontic appliances. The water flosser is significantly better than brushing alone, which most children and young adults do, or brushing and flossing.13 Additionally, research has demonstrated that patients who present with gingivitis, mild to moderate periodontitis, diabetes, and good oral hygiene can benefit from using a water flosser.5-9,27

Recommendation Suggestions

Product type: There are two basic designs on the market: countertop and cordless. Countertop models have large reservoirs and multiple pressure settings to accommodate personal preferences. Pricing is usually well below the cost of some leading power toothbrushes. Cordless units are smaller and power from rechargeable batteries. They tend to have fewer pressure settings and smaller reservoirs. These are good for individuals who travel or prefer not to have something on the counter.

Agent: Water has been shown to be a very effective agent. Most commercially available devices are designed to accept most mouthrinses and antimicrobial agents. Water is cost-effective, has no side effects, and is readily available.

Tip design: Different tip designs are available that can help customize recommendations for each patient. For example, a tip can be designed for placement below the gingival margin, which is especially useful for targeted delivery of antimicrobial agents in deep pockets. Tips may feature bristles designed for implants, crown and bridge, veneers, and other dental work. Tips can also be designed with a tapered brush for cleaning orthodontic appliances.


The patient’s ability to perform regular and effective self-care is important to the long-term success of therapeutic and restorative treatment and overall well-being. If patients are brushing and flossing and they have no clinical, radiographic, or other signs of infections, no major intervention is needed. However, if they are not flossing or have clinical signs of gingival or periodontal infection, then perhaps it is time to recommend an effective alternative such as a water flosser.


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2. Tedesco LA, Keffer MA, Fleck-Kandath C. Self-efficacy, reasoned action, and oral health behavior reports: a social cognitive approach to compliance. J Behav Med. 1991;14(4):341-355.

3. Christou V, Timmerman MF, Van der Velden U, Van der Weijden FA. Comparison of different approaches of interdental oral hygiene: interdental brushes versus dental floss. J Periodontol. 1998;69(7):759-764.

4. Berchier CE, Slot DE, Haps S, Van der Weijden GA. The efficacy of dental floss in addition to a toothbrush on plaque and parameters of gingival inflammation: a systematic review. Int J Dent Hygiene. 2008;6(4):265-279.

5. Hujoel PP, Cunha-Cruz J, Banting DW, Loesche WJ. Dental flossing and interproximal caries: a systematic review. J Dent Res. 2006;85(4):298-305.

6. Gorur A, Lyle DM, Schaudinn C, Costerton JW. Biofilm removal with a dental water jet. Compend Contin Ed Dent. 2009;30(spec iss 1):1-6.

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8. Cutler CW, Stanford TW, Abraham C, et al. Clinical benefits of oral irrigation for periodontitis are related to reduction of pro-inflammatory cytokine levels and plaque. J Clin Periodontol. 2000;27(2):134-143.

9. Flemmig TF, Epp B, Funkenhauser Z, et al. Adjunctive supragingival irrigation with acetylsalicylic acid in periodontal supportive therapy. J Clin Periodontol. 1995;22(6):427-433.

10. 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(3):71-77.

11. Al-Mubarak S, Ciancio S, Aljada A, et al. Comparative evaluation of adjunctive oral irrigation in diabetics. J Clin Periodontol. 2002;29(4):295-300.

12. Lobene RR. The effect of a pulsed water pressure cleansing device on oral health. J Periodontol. 1969;40(11):667-670.

13. Sharma NC, Lyle DM, Qaqish 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(4):565-571.

14. Rosema NA, Hennequin-Hoenderdos, NL, Berchier CE, et al. The effect of different interdental cleaning devices on gingival bleeding. J Int Acad Periodontol. 2011;13(1):2-10.

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16. Selting WJ, Bhaskar SN, Mueller RP. Water jet direction and periodontal pocket debridement. J Periodontol. 1972;43(9):569-572.

17. Ho PM, Spertus JA, Masoudi FA, et al. Impact of medication therapy discontinuation on mortality after myocardial infarction. Arch Intern Med. 2006;166(17):1842-1847.

18. Bloom BS. Daily regimen and compliance with treatment. BMJ. 2001;323(7314):647.

19. Macgregor ID, Balding JW, Regis D. Flossing behavior in English adolescents. J Clin Periodontol. 1998;25(4):291-296.

20. Stewart JE, Strack S, Graves P. Development of oral hygiene self-efficacy and outcome expectancy questionnaires. Community Dent Oral Epidemiol. 1997;25(5):337-342.

21. Bader HI. Floss or die: implications for dental professionals. Dent Today. 1998;17(7):76-82.

22. Just The Facts: Flossing. ADA Survey Center, ADA News, November 2007.

23. Ciancio S. Improving oral health: current considerations. J Clin Periodontol. 2003;30(suppl 5):4-6.

24. Hoover DR, Robinson HB. The comparative effectiveness of a pulsating oral irrigator as an adjunct in maintaining oral health. J Periodontol. 1971;42(1):37-39.

25. Lainson PA, Bergquist JJ, Fraleigh CM. A longitudinal study of pulsating water pressure cleansing devices. J Periodontol. 1972;43(7):444-446.

26. Felo A, Shibly O, Ciancio SG, et al. Effects of subgingival chlorhexidine irrigation on peri-implant maintenance. Am J Dent. 1997;10(2):107-110.

27. Chaves ES, Kornman KS, Manwell MA, et al. Mechanism of irrigation effects on gingivitis. J Periodontol. 1994;65(11):1016-1021.

About the Author

Deborah M. Lyle, RDH, MS
Director of Professional and Clinical Affairs
Water Pik, Inc.

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