Antimicrobial Resistance (AMR)SMARCHNCT07570927
Salivary Microbiota and Antimicrobial Resistance in Relation to Chlorhexidine Use
A study testing 0.06% Chlorhexidine Digluconate Toothpaste in people with Antimicrobial Resistance (AMR) and Oral Microbiota, run by Masaryk University at 2 sites in Czechia.
Trial summary
This study evaluated the ecological effects of 0.06% chlorhexidine toothpaste on the salivary microbiota of healthy individuals, focusing on taxonomic composition, functional shifts, and prevalence of predicted antimicrobial resistance genes. Read more about this study
- Who is it for?
- Ages 25 to 44 yearsHealthy volunteers can take part
- Conditions the study is for
- Antimicrobial Resistance (AMR), Oral Microbiota, Oral Microbiome Health
- What is being tested?
- 0.06% Chlorhexidine Digluconate Toothpaste
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 11 participants
- Where
- 2 sitesCzechia
- Study dates
- 11 Apr 2022to 29 Nov 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 25 to 44 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age: Between 25-44 years.
- General Health: Good systemic health (absence of chronic inflammatory diseases or conditions affecting oral tissues).
- Oral Hygiene Routine: Participants must perform toothbrushing twice a day and use interdental cleaning aids once a day.
- Plaque Index (PI): A score of 0.0-0.2 according to Silness and Löe.
- Gingival Index (GI): A score of 0.0-0.143 according to Silness and Löe.
Who cannot join
- Systemic and Lifestyle Factors:
- Presence of any chronic systemic disease (e.g., diabetes mellitus, autoimmune disorders)
- Regular use of medications that may affect gingival status or saliva production.
- Use of antibiotics within the last 6 months prior to the study.
- Current pregnancy or lactation.
- Current smokers or users of other tobacco/nicotine products.
Show all 10Show fewer
- Oral and Dental Factors:
- Active dental disease: Presence of untreated tooth decay, gingivitis (GI > 0.143), or any form of periodontitis.
- Prosthetics and Implants: Presence of dental implants, dentures, or significant tooth loss (excluding extracted third molars).
- Ongoing fixed or removable orthodontic treatment.
Trial locations and contacts
2 sites in 1 country.
Czechia2 sites
Department of Public Health, Faculty of Medicine, Masaryk University
Brno, 62500
Skydent s.r.o.
Brno, 62500
About this study
Official title: Study Protocol for 16S rRNA Sequencing of Healthy Oral Microbiota
This study evaluated the ecological effects of 0.06% chlorhexidine toothpaste on the salivary microbiota of healthy individuals, focusing on taxonomic composition, functional shifts, and prevalence of predicted antimicrobial resistance genes. Saliva samples were collected from eleven healthy participants at three specific time points: baseline (following a 4-week run-in period using a control toothpaste), intervention (after 12 weeks of using 0.06% chlorhexidine digluconate toothpaste), and washout (after a subsequent 12-week period using the control toothpaste). Sequencing targeted the 16S rRNA V3-V4 region.
- Conditions
- Antimicrobial Resistance (AMR), Oral Microbiota, Oral Microbiome Health, Chlorhexidine, Saliva Microbiome
- Being tested
- 0.06% Chlorhexidine Digluconate Toothpaste
- Keywords
- 0.06% Chlorhexidine, 16S rRNA Sequencing, Salivary Microbiota, Antimicrobial Resistance Genes, Taxonomic Composition, Long-term Effect, Washout Period
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
0.06% Chlorhexidine Digluconate ToothpasteDrug
Participants used the toothpaste twice daily for 12 weeks.
| Study group | Role | What they receive |
|---|---|---|
| Experimental: Chlorhexidine group | Experimental | A single group of 11 healthy volunteers. The study consists of three consecutive phases: baseline (4 weeks), intervention with 0.06% chlorhexidine toothpaste (12 weeks), and washout (12 weeks). Receives: Drug: 0.06% Chlorhexidine Digluconate Toothpaste |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Salivary Microbial Alpha Diversity (Shannon and Simpson Indices)
Evaluation of microbial richness and evenness within individual saliva samples. Alpha diversity is quantified using the Shannon and Simpson indices based on 16S rRNA gene sequencing data. Differences between study phases (baseline, intervention, washout) are assessed using the Kruskal-Wallis test or Mann-Whitney U test, as appropriate, with a significance threshold of p < 0.05.
Measured: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Change in Salivary Microbial Beta Diversity (Community Structure)
Evaluation of differences in microbial community composition between study phases. Calculated using Bray-Curtis dissimilarity on Centered Log-Ratio (CLR) normalized data and assessed via PERMANOVA to detect significant shifts (p < 0.05).
Measured: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Secondary outcomes (4)
Differential Abundance of Salivary Bacterial Taxa
Evaluation of shifts in the relative abundance of bacterial taxa (at phylum, family, genus, and species levels) using 16S rRNA sequencing (V3-V4 region). Statistical analysis is performed using DESeq2 and edgeR to identify significant differences between study phases, with multiple testing corrections applied using the Benjamini-Hochberg (FDR) method (FDR < 0.05).
Measured: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Changes in Predicted Antimicrobial Resistance Genes (ARGs)
Functional prediction of the salivary microbiota conducted using PICRUSt2. Assessment of metabolic potential and antimicrobial resistance pathways with significance assessed using adjusted p-values (p-adj < 0.05).
Measured: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Gingival Index (GI) for Clinical Stability Assessment
Assessment of gingival health using the Silness and Löe Gingival Index (scale 0-3). This measure is used to verify that participants maintain optimal oral health throughout the study. Eligibility is strictly limited to participants with a maximum GI of 0.143 at screening to ensure a healthy baseline and to monitor that no gingival inflammation occurs during the study period.
Measured: Screening (Week -4) and after washout (Week 24).
Plaque Index (PI) for Clinical Stability Assessment
Assessment of dental plaque accumulation using the Silness and Löe Plaque Index (scale 0-3). This measure is used to ensure consistent oral hygiene. Eligibility is strictly limited to participants with a maximum PI of 0.2 at screening. The index is monitored to confirm that participants adhere to the required oral hygiene protocol throughout the study.
Measured: Screening (Week -4) and after washout (Week 24).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 May 2026
- Study start11 Apr 2022
- Primary completion29 Nov 2022
- Study completion29 Nov 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Antimicrobial Resistance (AMR)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Health services research
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- Masaryk University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07570927
- Sponsor's protocol ID
- 68/2020
- Other IDs
- MUNI/A/1807/2025
- Acronym
- SMARCH
- Status last verified
- Apr 2026
- First submitted
- 30 Apr 2026
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Chuchmova V, Brodikova K, Zapletalova M, Lindholm M, Krsek M. Delayed shifts in salivary microbiota composition following long-term use of 0.06% chlorhexidine toothpaste. Front Oral Health. 2026 Aug 11;7:1887909. doi: 10.3389/froh.2026.1887909. eCollection 2026.
PubMed 42643364
Study at a glance
From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study Protocol for 16S rRNA Sequencing of Healthy Oral Microbiota
- ClinicalTrials.gov ID
- NCT07570927
- Acronym / sponsor ID
- SMARCH / 68/2020
- Conditions
- Antimicrobial Resistance (AMR), Oral Microbiota, Oral Microbiome Health, Chlorhexidine, Saliva Microbiome
- Keywords
- 0.06% Chlorhexidine, 16S rRNA Sequencing, Salivary Microbiota, Antimicrobial Resistance Genes, Taxonomic Composition, Long-term Effect, Washout Period
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- Masaryk UniversityUniversity, hospital or other
- Study start
- 11 Apr 2022 (actual)
- Primary completion
- 29 Nov 2022 (actual)
- Study completion
- 29 Nov 2022 (actual)
- First posted
- 6 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study evaluated the ecological effects of 0.06% chlorhexidine toothpaste on the salivary microbiota of healthy individuals, focusing on taxonomic composition, functional shifts, and prevalence of predicted antimicrobial resistance genes. Saliva samples were collected from eleven healthy participants at three specific time points: baseline (following a 4-week run-in period using a control toothpaste), intervention (after 12 weeks of using 0.06% chlorhexidine digluconate toothpaste), and washout (after a subsequent 12-week period using the control toothpaste). Sequencing targeted the 16S rRNA V3-V4 region.
Study design
- Primary purpose
- Health services research
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Experimental: Chlorhexidine group | Experimental | Drug: 0.06% Chlorhexidine Digluconate ToothpasteA single group of 11 healthy volunteers. The study consists of three consecutive phases: baseline (4 weeks), intervention with 0.06% chlorhexidine toothpaste (12 weeks), and washout (12 weeks). |
Who may qualify
- Ages
- 25 to 44 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Age: Between 25-44 years.
- General Health: Good systemic health (absence of chronic inflammatory diseases or conditions affecting oral tissues).
- Oral Hygiene Routine: Participants must perform toothbrushing twice a day and use interdental cleaning aids once a day.
- Plaque Index (PI): A score of 0.0-0.2 according to Silness and Löe.
- Gingival Index (GI): A score of 0.0-0.143 according to Silness and Löe.
Key exclusion criteria (10 listed)
- Presence of any chronic systemic disease (e.g., diabetes mellitus, autoimmune disorders)
- Regular use of medications that may affect gingival status or saliva production.
- Use of antibiotics within the last 6 months prior to the study.
- Current pregnancy or lactation.
- Current smokers or users of other tobacco/nicotine products.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 0.06% Chlorhexidine Digluconate ToothpasteParticipants used the toothpaste twice daily for 12 weeks. | Drug | Experimental: Chlorhexidine group |
Primary outcome
Change in Salivary Microbial Alpha Diversity (Shannon and Simpson Indices)
Time frame: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Evaluation of microbial richness and evenness within individual saliva samples. Alpha diversity is quantified using the Shannon and Simpson indices based on 16S rRNA gene sequencing data. Differences between study phases (baseline, intervention, washout) are assessed using the Kruskal-Wallis test or Mann-Whitney U test, as appropriate, with a significance threshold of p < 0.05.
Change in Salivary Microbial Beta Diversity (Community Structure)
Time frame: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Evaluation of differences in microbial community composition between study phases. Calculated using Bray-Curtis dissimilarity on Centered Log-Ratio (CLR) normalized data and assessed via PERMANOVA to detect significant shifts (p < 0.05).
4 secondary outcomes
Differential Abundance of Salivary Bacterial Taxa
Time frame: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Changes in Predicted Antimicrobial Resistance Genes (ARGs)
Time frame: Baseline (week 0), after intervention (week 12), and after washout (week 24).
Gingival Index (GI) for Clinical Stability Assessment
Time frame: Screening (Week -4) and after washout (Week 24).
Plaque Index (PI) for Clinical Stability Assessment
Time frame: Screening (Week -4) and after washout (Week 24).
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
- Derived from this study: PubMed 42643364Chuchmova V, Brodikova K, Zapletalova M, Lindholm M, Krsek M. Delayed shifts in salivary microbiota composition following long-term use of 0.06% chlorhexidine toothpaste. Front Oral Health. 2026 Aug 11;7:1887909. doi: 10.3389/froh.2026.1887909. eCollection 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing 0.06% Chlorhexidine Digluconate Toothpaste in people with Antimicrobial Resistance (AMR) and Oral Microbiota, run by Masaryk University at 2 sites in Czechia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Czechia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Salivary Microbial Alpha Diversity (Shannon and Simpson Indices) (time frame: Baseline (week 0), after intervention (week 12), and after washout (week 24).). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07570927, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.