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

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.

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.
40

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

  • 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

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

  • 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

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: 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

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
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Can Tho University of Medicine and Pharmacy

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University of Medicine and Pharmacy at Ho Chi Minh City

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

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.
September 5, 2023

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.
December 5, 2023

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.
March 5, 2024

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).
November 24, 2025

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.
November 24, 2025

First Posted (Estimated)

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.
December 4, 2025

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.
December 22, 2025

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.
December 16, 2025

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.
December 1, 2025

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.
  • 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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