Comparison of Water Flosser and Interdental Brush on Reduction of Gingival Bleeding and Plaque: A Randomized Controlled Pilot Study

J Clin Dent. 2016 Jun;27(2):61-65.


Objectives: The purpose of this randomized, two-week, single blind, two-group parallel pilot study was to compare the reduction in gingival bleeding and plaque in subjects using a water flosser or interdental brush, each combined with a manual toothbrush.

Methods: Twenty-eight subjects completed the study. Subjects were randomly assigned to one of two groups: Waterpik® Water Flosser (WF) plus manual toothbrush or interdental brushes (IDBs) plus a manual toothbrush. Bleeding on probing (BOP) was measured at six sites and reported for whole mouth, lingual, facial, and interproximal areas. Plaque data were measured using the Rustogi Modification of the Navy Plaque Index (RMNPI) and were reported for whole mouth, approximal, marginal, facial, and lingual areas. Subjects received verbal and written instructions on the use of their interdental product and demonstrated proficiency prior to starting the study.

Results: There were no differences between the groups for BOP or RMNPI at baseline. Both groups demonstrated a significant reduction in BOP and RMNPI for all regions and areas measured from baseline to two weeks. The WF was more effective than the IDBs for BOP whole mouth (56%), facial (44%), approximal whole mouth (53%), and approximal facial (41%). Post hoc power analysis showed that the sample size was not adequate to detect a significant difference between groups for lingual and marginal assessments for BOP or any area for RMNPI.

Conclusions: The Waterpik Water Flosser is more effective than IDBs for reducing gingival bleeding over two weeks.

Keywords: Waterpik; bleeding on probing; gingival inflammation; gingivitis; interdental; interdental brush; interproximal brush; plaque; water flosser.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Dental Devices, Home Care*
  • Dental Plaque Index
  • Dental Plaque*
  • Equipment Design
  • Gingival Hemorrhage*
  • Gingivitis
  • Humans
  • Periodontal Index
  • Pilot Projects
  • Single-Blind Method
  • Toothbrushing*
  • Water*


  • Water