Salivary Microbiota and Antimicrobial Resistance in Relation to Chlorhexidine Use

NCT07570927 | Completed

• 2 other identifiers: 68/2020MUNI/A/1807/2025
• Study Type: interventional
• Target: 11
• Locations: 1 country
• Sites: 2

Brief 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. 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

Keywords

0.06% Chlorhexidine; 16S rRNA Sequencing; Salivary Microbiota; Antimicrobial Resistance Genes; Taxonomic Composition; Long-term Effect; Washout Period

Outcome Measures

Primary Outcomes (2)

• 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.

  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).

  Baseline (week 0), after intervention (week 12), and after washout (week 24).

Secondary Outcomes (4)

• Differential Abundance of Salivary Bacterial Taxa

  Baseline (week 0), after intervention (week 12), and after washout (week 24).

• Changes in Predicted Antimicrobial Resistance Genes (ARGs)

  Baseline (week 0), after intervention (week 12), and after washout (week 24).

• Gingival Index (GI) for Clinical Stability Assessment

  Screening (Week -4) and after washout (Week 24).

• Plaque Index (PI) for Clinical Stability Assessment

  Screening (Week -4) and after washout (Week 24).

Study Arms (1)

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).

Drug: 0.06% Chlorhexidine Digluconate Toothpaste

Interventions

0.06% Chlorhexidine Digluconate Toothpaste DRUG

Participants used the toothpaste twice daily for 12 weeks.

Experimental: Chlorhexidine group

Eligibility Criteria

• Age: 25 Years - 44 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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.
• 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.

Sponsors & Collaborators

• Masaryk University: lead

Study Sites (2)

Department of Public Health, Faculty of Medicine, Masaryk University

Brno, 62500, Czechia

Location

Skydent s.r.o.

Brno, 62500, Czechia

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 30, 2026
• First Posted: May 6, 2026
• Study Start: April 11, 2022
• Primary Completion: November 29, 2022
• Study Completion: November 29, 2022
• Last Updated: May 6, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CZ (2)