Antimicrobial Resistance (AMR), Chlorhexidine, Oral Microbiome Health, Oral Microbiota, Saliva Microbiome
Conditions
Keywords
0.06% Chlorhexidine, 16S rRNA Sequencing, Salivary Microbiota, Antimicrobial Resistance Genes, Taxonomic Composition, Long-term Effect, Washout Period
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.
Interventions
DRUG0.06% Chlorhexidine Digluconate Toothpaste
Participants used the toothpaste twice daily for 12 weeks.
Sponsors
Masaryk University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
HEALTH_SERVICES_RESEARCH
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
25 Years to 44 Years
Healthy volunteers
Yes
Inclusion criteria
* 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.
Exclusion criteria
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Salivary Microbial Alpha Diversity (Shannon and Simpson Indices) | 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) | 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). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Differential Abundance of Salivary Bacterial Taxa | Baseline (week 0), after intervention (week 12), and after washout (week 24). | 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). |
| Changes in Predicted Antimicrobial Resistance Genes (ARGs) | Baseline (week 0), after intervention (week 12), and after washout (week 24). | 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). |
| Gingival Index (GI) for Clinical Stability Assessment | Screening (Week -4) and after washout (Week 24). | 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. |
| Plaque Index (PI) for Clinical Stability Assessment | Screening (Week -4) and after washout (Week 24). | 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. |
Countries
Czechia
Outcome results
None listed