Evaluation of Bacterial Contamination and Antimicrobial Efficacy on Charcoal-Infused vs, Standard Nylon Toothbrush Bristles.

January 19, 2026 updated by: Esraa Hamed Aly, MTI University

This study compares two types of toothbrushes to see which one stays cleaner after use. Researchers want to know if toothbrushes with charcoal-infused bristles have fewer bacteria than standard toothbrushes with nylon bristles.

Participants in this study are adults and children who do not have gum disease or other major health issues. Everyone in the study will be assigned one of two types of toothbrushes:

  • An eco-friendly toothbrush with charcoal bristles.
  • A standard toothbrush with nylon bristles. Participants will use their assigned toothbrush at home for two specific time periods (one day and one week). They will follow simple instructions on how to brush and store the toothbrush. After each time period, they will return the toothbrush to the researchers.

The research team will test the bristles in a lab to count the bacteria. They will also measure how well the charcoal bristles stop bacteria from growing compared to the nylon bristles. This will help determine if charcoal toothbrushes are a more sanitary and eco-friendly option for daily oral care.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Study Design and Randomization This study employs a randomized, parallel-group, ex-vivo microbiological design to assess bacterial retention and antimicrobial efficacy. Participants are stratified by age (children and adults) and randomized to receive either an eco-friendly charcoal-infused toothbrush or a standard nylon toothbrush. Allocation is managed using computer-generated random sequences concealed in sequentially numbered, opaque envelopes. To maintain blinding, laboratory outcome assessors are unaware of group assignment, and participants are instructed not to disclose their intervention to the assessment team.

Standardized Usage Protocol

To minimize variability in bacterial load due to behavioral factors, all participants adhere to a strict hygiene protocol:

  • Brushing Technique: Participants brush twice daily (morning and evening) for two minutes using a standardized method (45-degree angle to the gingiva with short back-and-forth strokes, and vertical strokes for anterior lingual surfaces).
  • Storage and Maintenance: Post-brushing, bristles are rinsed under running water without digital manipulation. Toothbrushes must be stored upright, uncovered, and positioned at least two feet away from sanitary fixtures (e.g., toilets) to minimize aerosol contamination.
  • Restrictions: The use of antimicrobial mouthrinses, medicated toothpastes, or bristle covers is prohibited during the active study phases.

Sample Collection Timeline

The study involves two distinct usage periods separated by a washout phase:

  1. Phase 1 (24-Hour Assessment): Participants use the assigned toothbrush for one day, followed by immediate return in a sterile pouch.
  2. Washout: A 7-day period occurs where participants revert to their non-study oral hygiene routine.
  3. Phase 2 (7-Day Assessment): Participants receive a new toothbrush of the same allocation, use it for 7 days, and return it in a sterile pouch for analysis.

Microbiological Analysis Returned samples are processed under aseptic laboratory conditions. Approximately one-third of the bristle field is excised using sterile instrumentation and transferred to test tubes containing 5 mL of sterile saline. The tubes are agitated to elute adherent microorganisms into suspension. A 0.1 mL aliquot is inoculated onto blood agar plates using a sterile spreader.

Plates are incubated in anaerobic gas pack jars at 37°C. Colony Forming Units (CFUs) are quantified after 48 hours of incubation to determine total bacterial load. Additionally, the intrinsic antimicrobial activity of the bristles is evaluated by measuring the zone of inhibition (in millimeters) surrounding bristle samples placed on agar plates after 7days of incubation.

Study Type

Interventional

Enrollment (Actual)

36

Phase

  • 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

  • Egypt
      • Cairo, Egypt, 11585
        • Dental clinic

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

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Participants free of any systemic diseases.
  • Participants falling into one of two specific age groups:

A) Children aged 8 to 11 years.

B) Adults aged 18 to 35 years.

  • Willingness to use the assigned toothbrush type (Eco-friendly charcoal or standard nylon).
  • Ability to follow study instructions regarding brushing technique and storage.

Exclusion Criteria:

  • Patients with open carious lesions.
  • Participants with poor oral hygiene, defined as plaque index scores greater than 2.
  • Participants with severe gingivitis, defined as gingival index score greater than 2.
  • Current throat infections.
  • Irregular brushing frequency (not brushing twice daily).
  • Current use of mouthwash or antibacterial toothpastes.
  • Current smokers.
  • Medically compromised individuals.
  • Unwillingness to use a charcoal Eco-friendly toothbrush.

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: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Antimicrobial effect of Eco-friendly tooth brush in children
this arm will use the Eco-friendly toothbrush and will be evaluated for its antimicrobial effect
Device: Eco-friendly toothbrush for children
it is an eco-friendly charcoal toothbrush assumed to have antibacterial property in children
Experimental: Antimicrobial effect of Eco-friendly tooth brush in adults
this arm will use the eco-friendly toothbrush and tested for its antimicrobial effect in adults
Device: Eco-friendly toothbrush in adults
to see the antimicrobial effect of eco-friendly toothbrush in adults
Active Comparator: Nylon bristles toothbrush in children
this arm will use the nylon toothbrush bristles and be evaluated for its antibacterial effect
Device: nylon bristles toothbrush in children
a normal man made toothbrush used by children
Active Comparator: nylon toothbrush bristles in adults
this arm will use the nylon bristles toothbrush and be evaluated for its antimicrobial effect
Device: Nylon bristles toothbrush in adults
a normal man made toothbrush used by adults

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Colony-forming units (CFU)
Time Frame: 10 days
Bacterial load will be quantified as CFU per milliliter (CFU/mL) from toothbrush bristles after 1 day and 1 week of use. One-third of the bristles will be aseptically cut, placed in 5 mL sterile saline, mixed to elute bacteria, then 0.1 mL will be plated onto blood agar. Plates will be incubated under anaerobic conditions for 48 hours, then colonies will be counted and recorded as CFU/mL.
10 days

Collaborators and Investigators

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

Sponsor

MTI University

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)

November 11, 2025

Primary Completion (Actual)

December 20, 2025

Study Completion (Actual)

January 1, 2026

Study Registration Dates

First Submitted

January 4, 2026

First Submitted That Met QC Criteria

January 19, 2026

First Posted (Actual)

January 26, 2026

Study Record Updates

Last Update Posted (Actual)

January 26, 2026

Last Update Submitted That Met QC Criteria

January 19, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • SUEZ Med - IRB Approval No: 95

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

age, gender

IPD Sharing Time Frame

october 2025 to october 2026

IPD Sharing Supporting Information Type

  • ICF
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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