Comparison of irrigation to floss as an adjunct to tooth brushing: effect on bleeding, gingivitis, and supragingival plaque

J Clin Dent. 2005;16(3):71-7.


Objective: The purpose of this twenty-eight day, randomized, single-blind clinical trial was to assess the efficacy of the addition of daily oral irrigation to both power and manual tooth brushing, compared to a traditional regimen of manual tooth brushing and flossing, to determine which regimen had the greatest effect on the reduction of gingival bleeding, gingivitis, and supragingival plaque.

Methodology: The study was designed for a total of 105 subjects to participate in a twenty-eight day trial, with 35 subjects randomly assigned to one of three groups: Group 1-manual toothbrush and floss; Group 2-manual toothbrush and dental water jet; and Group 3-sonic toothbrush and dental water jet. All subjects received written and verbal instructions for using their regimens. Subjects were asked to brush for a timed two minutes, twice per day, with the brush and the dentifrice provided, and to refrain from using any additional oral hygiene aids. Subjects using the dental water jet were instructed to use the water jet on a medium setting, irrigating once per day with 500 ml of luke warm water. Subjects using the dental floss were instructed to use the floss once daily. Subjects were examined by two calibrated examiners, and data were collected at baseline (BSL), 14 days (D14), and 28 days (D28). Subjects were asked to abstain from any oral hygiene for 12 hours prior to each study visit. Subjects were scored using the Carter and Barnes Bleeding Index, Löe and Silness Gingival Index, and the Proximal/Marginal Plaque Index. Mean scores on the three indices for the three groups were used for statistical analysis at each time point. Additionally, the means were used for comparisons as change from baseline and percent change from baseline at D14 and D28. The significance of percentage change in each index from baseline to D14 and D28 was evaluated using a one-tailed t-test. Significant differences are reported at alpha < or = 0.05 for these planned group comparisons.

Results: Thirty-one subjects in Group 1, 32 subjects in Group 2, and 32 subjects in Group 3 completed the study. Bleeding Index: Groups 2 and 3, the irrigation groups, were statistically significantly more effective than Group 1 in reducing the bleeding index at D14 and D28, whether measured by mean reduction or percentage reduction. Gingival Index: At D14, both irrigation groups demonstrated a statistically significantly greater reduction in the gingival index compared to brushing and flossing for the facial surfaces. There was no significant difference between groups for the lingual surface at D14. At D28 there was a significant difference between Groups 1 and 2 for both the facial and lingual surfaces. Plaque Index: There was one significant difference between groups for the plaque index measured on the lingual surfaces. The manual toothbrush and floss were less effective than the sonic toothbrush and irrigation. Group 3 was also significantly better than Group 1 in reducing the plaque index on the facial surfaces at both D14 and D28. On plaque percentage reduction on the facial surface, Group 2 was significantly better than Group 1 at D14. There was no statistical difference between Group 1 and Group 2 at D28.

Conclusion: The results of this clinical trial indicate that when combined with manual or sonic tooth brushing, oral irrigation is an effective alternative to manual tooth brushing and dental floss for reducing bleeding, gingival inflammation, and plaque removal.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Dental Devices, Home Care*
  • Dental Plaque / prevention & control*
  • Dental Plaque Index
  • Female
  • Gingivitis / prevention & control*
  • Humans
  • Male
  • Middle Aged
  • Periodontal Index
  • Single-Blind Method
  • Therapeutic Irrigation / instrumentation*
  • Toothbrushing
  • Water / administration & dosage*


  • Water