Effect of a Mouthwash Containing Chlorhexidine and Chlorine Dioxide on Halitosis (CHX+CDO)

December 16, 2025 updated by: Can Tho University of Medicine and Pharmacy

A Randomized Double-Blind Crossover Clinical Trial Evaluating the Efficacy of a Mouthwash Containing Chlorhexidine and Chlorine Dioxide in Patients With Oral Malodor

Halitosis significantly impacts the quality of a patient's life. This randomized, double-blind crossover trial evaluates a mouthwash containing chlorhexidine (0.01%) and chlorine dioxide (0.05%) compared with placebo. Forty participants rinsed twice daily for 2 weeks, followed by a 2-week washout and crossover. The primary outcomes were volatile sulfur compounds (H₂S, CH₃SH), measured by OralChroma. Secondary outcomes included plaque index, gingival index, bleeding on probing, tongue coating, and salivary bacterial counts (Aa, Pg, Fn, Pi, and Ec).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

40

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

  • Vietnam
      • Ho Chi Minh City, Vietnam, 70000
        • Odonto-Stomatology Hospital of Ho Chi Minh City

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • ≥20 natural teeth
  • H₂S >1.5 ng/10ml or CH₃SH >0.5 ng/10ml
  • Signed informed consent

Exclusion Criteria:

  • Systemic disease
  • Smoking
  • Pregnancy or lactation
  • Periodontal pockets ≥4 mm
  • Recent antibiotic use (<1 month)
  • Orthodontic appliances or dentures
  • Allergy to CHX or C

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: CHX-CDO Mouthwash
Participants rinsed with a test mouthwash containing 0.01% chlorhexidine and 0.05% chlorine dioxide. Each participant used 15 mL of the solution twice daily (morning and evening) for 30 seconds over a period of 2 weeks. The mouthwash bottles were identical in appearance to maintain blinding.
Other: CHX 0.01% + CDO 0.05% mouthwash
Mouthwash formulation containing chlorhexidine 0.01% and chlorine dioxide 0.05%, prepared by the Department of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City.
Other Names:
  • CHX+ CDO mouthwash
Placebo Comparator: Placebo Mouthwash
Participants rinsed with a placebo mouthwash containing the same excipients, color, and flavoring agents but without chlorhexidine or chlorine dioxide. Each participant used 15 mL of the placebo solution twice daily for 30 seconds over 2 weeks.
Other: Placebo mouthwash
Identical placebo formulation matched in flavor, color, and excipients but without active ingredients (CHX or CDO).
Other Names:
  • Control mouthwash

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Hydrogen sulfide (H₂S) concentration in breath
Time Frame: baseline, immediate post-rinse, 2 weeks
The concentration of hydrogen sulfide (H₂S) in oral breath was measured using the OralChroma™ device. The difference between baseline, immediately after rinsing, and 2 weeks was used to assess the efficacy of the mouthwash in reducing volatile sulfur compounds.
baseline, immediate post-rinse, 2 weeks
Change in Methyl mercaptan (CH₃SH) concentration in breath
Time Frame: Baseline, immediate post-rinse, 2 weeks
The concentration of methyl mercaptan (CH₃SH) in oral breath was measured using the OralChroma™ device. The difference between baseline, immediately after rinsing, and 2 weeks was used to evaluate the short-term and sustained effects of the mouthwash on halitosis.
Baseline, immediate post-rinse, 2 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change of plaque index
Time Frame: At baseline and 2 weeks of mouthwash use
The Plaque Index (PI) was recorded at four surfaces per tooth (mesiobuccal, buccal, distobuccal, and lingual) to assess plaque accumulation. Each surface was scored on a scale from 0 to 3, where 0 indicates no plaque and 3 indicates abundant plaque accumulation. The mean PI score per participant was calculated at each visit. A lower score indicates less plaque accumulation and improved oral hygiene.
At baseline and 2 weeks of mouthwash use
Change in Gingival Index (GI)
Time Frame: At baseline and 2 weeks of mouthwash use
The Gingival Index (GI) was evaluated at four surfaces per tooth (mesiobuccal, buccal, distobuccal, and lingual) to assess the degree of gingival inflammation. Each surface was scored on a scale from 0 to 3, where 0 indicates normal gingiva and 3 indicates severe inflammation with marked redness, edema, and a tendency to spontaneous bleeding. The mean GI score per participant was calculated. A lower score reflects healthier gingival conditions.
At baseline and 2 weeks of mouthwash use
Change in Bleeding on Probing (BOP)
Time Frame: At baseline and 2 weeks of mouthwash use
The percentage of sites showing bleeding upon gentle probing was recorded as an indicator of gingival inflammation and bleeding tendency. The presence of bleeding was recorded at each examined site following gentle periodontal probing. BOP was expressed as the percentage of bleeding sites, calculated as the number of sites showing bleeding divided by the total number of sites examined ×100%. Higher percentages indicate greater gingival inflammation.
At baseline and 2 weeks of mouthwash use
Change in Tongue Coating Index
Time Frame: At baseline and 2 weeks of mouthwash use
The tongue dorsum was visually divided into six areas (three anterior and three posterior) according to Winkel's Tongue Coating Index (WTCI). Each area was scored from 0 (no coating), 1 (mild coating), and 2 (thick coating), and the total score (0-12) was calculated as the Tongue Coating Index.
At baseline and 2 weeks of mouthwash use
Change in salivary bacterial load (qPCR quantification)
Time Frame: At baseline and 2 weeks of mouthwash use
Salivary bacterial counts of Porphyromonas gingivalis, Fusobacterium nucleatum, Prevotella intermedia, Eikenella corrodens, and Aggregatibacter actinomycetemcomitans were quantified using real-time PCR (qPCR). Changes in bacterial load (log CFU/mL) between baseline and 2 weeks were compared to assess the antibacterial effect of the mouthwash.
At baseline and 2 weeks of mouthwash use

Collaborators and Investigators

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

Sponsor

Can Tho University of Medicine and Pharmacy

Collaborators

University of Medicine and Pharmacy at Ho Chi Minh City

Investigators

  • Principal Investigator: Thuy A.V. Pham, Assoc.Prof., Can Tho University of Medicine and Pharmacy

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)

September 5, 2023

Primary Completion (Actual)

December 5, 2023

Study Completion (Actual)

March 5, 2024

Study Registration Dates

First Submitted

November 24, 2025

First Submitted That Met QC Criteria

November 24, 2025

First Posted (Estimated)

December 4, 2025

Study Record Updates

Last Update Posted (Actual)

December 22, 2025

Last Update Submitted That Met QC Criteria

December 16, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CHXCDO-Halitosis-2022

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified data, study protocol, and statistical code will be available upon reasonable request

IPD Sharing Time Frame

Within 6 months after publication, available for 3 years

IPD Sharing Access Criteria

Researchers with IRB-approved proposals may request access via corresponding author.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

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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