Charcoal Toothbrushes and Bacterial Contamination: a Clinical Trial.

NCT07275684 | Completed

• 1 other identifier: CERB 44-25
• Study Type: interventional
• Target: 32
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized controlled clinical trial aims to evaluate the antibacterial effectiveness of toothbrushes with charcoal-impregnated bristles compared to conventional toothbrushes without charcoal. The main objective is to assess and compare the microbial contamination on the toothbrushes after 21 days of use. Thirty-two healthy dental students from the Faculty of Dental Medicine of Rabat (16 males and 16 females, aged 18-24) were enrolled through convenience sampling. Participants were randomly assigned to two groups: Group A: Colgate Double Action Medium toothbrushes with charcoal-impregnated bristles. Group B: Colgate Double Action Medium toothbrushes without charcoal (control group). Participants brushed their teeth twice daily for two minutes using the rolling technique and a standardized fluoride toothpaste (1450 ppm). They were instructed not to use mouthwash or antiseptic toothpaste, to rinse brushes only with tap water (without touching the bristles), to store them vertically with bristles facing upward, and to keep them uncovered and at least one meter away from toilets. After 21 days, used toothbrushes were collected in sterile pouches and transferred to the microbiology laboratory. A quarter of the bristles from each brush head was aseptically cut, immersed in sterile saline solution, and vortexed to dislodge microorganisms. Aliquots of 200 µL were inoculated onto blood agar (Columbia agar base enriched with sterile blood). After incubation at 37°C for 48 hours, colony-forming units (CFU) were manually counted to estimate microbial contamination levels (CFU/mL). Clinical data (Silness and Löe plaque index, Löe and Silness gingival index, and DMF index) were collected at baseline. Statistical analysis was performed using Jamovi software. The comparison of CFU counts between groups aimed to determine whether charcoal impregnation reduces microbial contamination of toothbrush bristles. This study involves minimal risk and no investigational drug or device. Ethical approval was obtained from the Ethics Committee of the Faculty of Dental Medicine of Rabat.

Conditions

Oral Hygiene; Toothbrush Contamination; Bacterial Contamination

Keywords

Charcoal toothbrush; Oral hygiene

Outcome Measures

Primary Outcomes (1)

• Reduction of microbial contamination on toothbrush bristles

  The primary outcome is the number of colony-forming units (CFU/mL) measured on toothbrush bristles after 21 days of use. A quarter of the bristles from each brush is cut and placed in sterile saline, vortexed to create a suspension, and 200 µL is inoculated on blood agar plates. Plates are incubated at 37°C for 48 hours, and CFU are counted manually. This outcome assesses the effectiveness of charcoal-impregnated bristles in reducing microbial contamination compared to conventional toothbrushes.

  21 days

Study Arms (2)

Charcoal-Impregnated Toothbrush

EXPERIMENTAL

Participants use a Colgate Double Action Medium toothbrush with charcoal-impregnated bristles twice daily for 2 minutes using the rolling technique. They use standardized fluoride toothpaste (1450 ppm) and follow instructions for proper storage: vertical position, bristles up, uncovered, at least 1-2 meters from toilets. Participants record their daily brushing in a standardized log sheet.

Device: Charcoal-Impregnated Toothbrush

Conventional Toothbrush

ACTIVE COMPARATOR

Participants use a Colgate Double Action Medium toothbrush without charcoal twice daily for 2 minutes using the rolling technique. They use the same standardized fluoride toothpaste (1450 ppm) and follow the same storage and logging instructions as Arm 1.

Device: Conventional Toothbrush

Interventions

Charcoal-Impregnated Toothbrush DEVICE

Participants use the Colgate Double Action Medium toothbrush with charcoal bristles as described in Arm 1. Daily brushing is twice for 2 minutes, using the rolling technique, with standardized fluoride toothpaste (1450 ppm). Proper storage instructions and daily log recording are followed.

Charcoal-Impregnated Toothbrush

Conventional Toothbrush DEVICE

Participants use the Colgate Double Action Medium toothbrush without charcoal bristles as described in Arm 2. Daily brushing is twice for 2 minutes, using the rolling technique, with standardized fluoride toothpaste (1450 ppm). Proper storage instructions and daily log recording are followed.

Conventional Toothbrush

Eligibility Criteria

• Age: 18 Years - 24 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Students of the Faculty of Dental Medicine of Rabat (4th or 5th year) aged 18-24 years.
• In good general health with no systemic diseases.
• Regular users of manual toothbrushes, brushing at least twice daily.
• Informed about the study and have signed informed consent.
• Willing to use the assigned toothbrush and follow study instructions for brushing technique, toothpaste use, and storage of the toothbrush.

You may not qualify if:

• Irregular frequency of tooth brushing.
• Unwillingness to use a charcoal-impregnated toothbrush or known allergy to activated charcoal.
• Use of antiseptic mouthwash and/or antiseptic toothpaste.
• Smoking.
• Presence of systemic disease.
• Current or recent antibiotic therapy (within the 4 weeks prior to the study).
• High plaque index (\>2, Silness \& Löe).
• Periodontitis.
• Severe gingivitis (gingival index \>2, Löe \& Silness).
• Wearing orthodontic appliances.
• Current oro-pharyngeal infections.

Sponsors & Collaborators

• Mohammed V University in Rabat: lead
• Oral Biotechnology Laboratory, Faculty of Dental Medicine, Mohammed V University in Rabat: collaborator

Study Sites (1)

Faculty of Dental Medicine of Rabat, Mohammed V University

Rabat, Al Irfane, 6212, Morocco

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Specialist in Conservative Dentistry, Faculty of Dental Medicine Rabat

Study Record Dates

• First Submitted: November 28, 2025
• First Posted: December 10, 2025
• Study Start: April 16, 2025
• Primary Completion: May 30, 2025
• Study Completion: June 11, 2025
• Last Updated: December 10, 2025

Record last verified: 2025-11

Locations

MO (1)