Water Flossing Versus Dental Floss for Oral Hygiene in Children Aged 10-15 Years: A Randomized Trial

March 16, 2026 updated by: Shahad Abudawood, King Abdulaziz University

The Effectiveness of Water Flossing Versus Regular Flossing for Oral Hygiene in Children Aged 10-15 Years: A Randomized Clinical Trial

The goal of this Randomized Clinical Trial is to compare the effectiveness of water flossing versus regular flossing in reducing dental plaque in children aged 10-15 years. The main question is the water flossing equal or more effective than regular flossing. Each participant will use both interdental cleaning methods, water flossing and regular flossing, in two separate visits and the plaque Index (PI) will be recorded.

Regular Dental Floss Group: Unflavored, unwaxed regular dental floss (Oral-B, USA), or Water Flosser: Water flosser (Waterpik Cordless Plus Water Flosser, USA)

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Ethical Approval:

The study protocol was reviewed and approved by the Research Ethics Committee of the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia. Written informed consent was obtained from all parents or legal guardians prior to participation, in accordance with the Declaration of Helsinki.

Study Design:

This study was designed as a randomized, controlled crossover clinical trial. Each participant used both interdental cleaning methods, water flossing and regular flossing, in two separate visits with a 14-day washout period between interventions to minimize carryover effects.

Study Setting:

The study was conducted at the College of Dentistry and the University Dental Hospital, King Abdulaziz University, Jeddah, Saudi Arabia.

Sample Selection:

Participants were recruited using a convenience sampling approach from patients attending the College of Dentistry and the University Dental Hospital at King Abdulaziz University. Eligible participants who met the inclusion criteria were enrolled after obtaining informed parental consent.

Randomization (Sequence Generation) Random allocation sequences were generated using an online randomization tool (https://www.randomizer.org). Two sets of random numbers were created, corresponding to the two intervention orders.

Allocation Concealment:

Each allocation code was printed, cut into identical slips, and sealed in opaque envelopes. The envelopes were placed in a single container. Upon recruitment, each participant selected one envelope to determine their assigned intervention sequence.

Blinding:

Due to the nature of the interventions, blinding of the participants and operators was not feasible. However, the statistician responsible for data analysis was blinded to the group assignments to minimize analytical bias.

Inclusion and Exclusion Criteria:

The inclusion criteria included children aged 10-15 years, medically fit and systemically healthy, with no active orthodontic treatment or space maintainer with no use of any type of dental floss within the previous 24 hours. Children with fewer than four posterior proximal contacts were excluded from the study.

Sample Size Calculation:

The sample size was calculated using G*Power software (version 3.1.9.7), based on the findings of a previous study who compared the efficacy of water flossers and regular floss in plaque removal. Assuming a power of 80%, a two-tailed significance level (α) of 0.05, and an effect size derived from the cited study, a total of 44 participants (22 per group) were required to achieve sufficient statistical power.

Study Procedures:

Participants were screened according to the inclusion and exclusion criteria. Parents were informed that participation was voluntary and that all collected data would remain confidential and accessible only to the research team.

Each participant was randomly assigned to start with one of the following:

  • Regular Dental Floss: Unflavored, unwaxed regular dental floss (Oral-B, USA), or
  • Water Flosser Group: Water flosser (Waterpik Cordless Plus Water Flosser, USA).
  • both are FDA-regulated medical devices (Class I). After the first visit, a 14-day washout period was observed before the crossover intervention was applied.

At the first visit, demographic data (participant initials, age, and sex) and group allocation were recorded. A clinical examination was performed to assess the Plaque Index (PI). All participants received standardized oral hygiene instructions, including brushing twice daily with the Modified Bass Technique using a soft-bristled toothbrush and fluoridated toothpaste. Participants received instructions on the proper use of the assigned interdental cleaning method and performed the procedure independently.

The Plaque Index (PI) was recorded for all teeth according to the following criteria:

  • 0: No plaque in the gingival area.
  • 1: A film of plaque adhering to the free gingival margin and adjacent tooth area, detectable only by a probe.
  • 2: Moderate accumulation of soft deposits visible to the naked eye within the gingival margin.
  • 3: Abundant soft matter within the gingival pocket and/or along the gingival margin.

At the second visit, participants switched to the opposite cleaning method (water flosser or regular floss), and plaque scores were reassessed using the same PI criteria.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
55

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Saudi Arabia
      • Jeddah, Saudi Arabia
        • King Abdulaziz University- Peditaric dentistry clinics

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • The inclusion criteria included children aged 10-15 years, medically fit and systemically healthy, with no active orthodontic treatment or space maintainer with no use of any type of dental floss within the previous 24 hours.

Exclusion Criteria:

  • Children with fewer than four posterior proximal contacts were excluded from the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Regular Dental Floss
Unflavored, unwaxed regular dental floss (Oral-B, USA)
Device: Unflavored, unwaxed regular dental floss (Oral-B, USA)
Plaque removal
Other Names:
  • Group A
Device: Water flosser (Waterpik Cordless Plus Water Flosser, USA)
Plaque removal
Experimental: Water Flosser
Water flosser (Cordless Plus Water Flosser, USA)
Device: Unflavored, unwaxed regular dental floss (Oral-B, USA)
Plaque removal
Other Names:
  • Group A
Device: Water flosser (Waterpik Cordless Plus Water Flosser, USA)
Plaque removal

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Plaque Index (PI)
Time Frame: 16 days, 1st visit followed by 14 days washout period then 2nd visit
to assess the Plaque Index (PI) using the criteria of Silness and Löe (1964).
16 days, 1st visit followed by 14 days washout period then 2nd visit

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
King Abdulaziz University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 30, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 30, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 26, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 9, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 13, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 169-11-24

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Due to privacy

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Conditions

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