Assessing the Impact on dental biofilm of Heyndrickxia coagulans administered through sugar-free chewing gum
| ISRCTN | ISRCTN13055033 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN13055033 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Protocol serial number | Nil known |
| Sponsor | University of Milan |
| Funder | Investigator initiated and funded |
- Submission date
- 03/11/2025
- Registration date
- 04/12/2025
- Last edited
- 05/11/2025
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Oral Health
Plain English summary of protocol
Background and study aims
This study is looking at whether a probiotic called Heyndrickxia coagulans (H. coagulans), delivered through sugar-free chewing gum, can settle in dental plaque and possibly improve oral health. Researchers want to understand how this probiotic affects the mix of bacteria in dental plaque.
Who can participate?
Healthy adults aged 18 to 64 years can take part, as long as they have at least 24 natural teeth (excluding wisdom teeth), good gum and plaque scores, and a normal saliva flow. People with certain health conditions, pregnant or breastfeeding women, smokers, those with braces, or anyone allergic to ingredients in the gum cannot take part.
What does the study involve?
Participants will be randomly assigned to one of two groups: one will chew gum containing the probiotic, and the other will chew gum without it. Everyone will receive a toothbrush and fluoride toothpaste and be asked to follow specific oral hygiene instructions. They’ll chew the gum five times a day for four weeks, after a two-week preparation period. There will also be a one-week follow-up phase. Participants will keep a diary of their gum use and bring back empty packs to help researchers track compliance. Dental plaque samples will be collected and analysed to see how the bacteria change over time.
What are the possible benefits and risks of participating?
The study may help improve understanding of how probiotics affect oral health, which could benefit future dental care. Risks are minimal but may include mild reactions to ingredients in the gum. Anyone who experiences side effects or needs to take antibiotics or other restricted products during the study will be withdrawn.
Where is the study run from?
University of Milan, Italy.
When is the study starting and how long is it expected to run for?
January 2024 to April 2025
Who is funding the study?
Investigator initiated and funded
Who is the main contact?
Dr Silvia Cirio, silvia.cirio@unimi.it
Contact information
Public, Scientific, Principal investigator
Via Beldiletto, 1
Milan
20121
Italy
 ORCID ID |
0000-0002-3531-2595 |
|---|---|
| Phone | +39 3478436387 |
| silvia.cirio@unimi.it |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Double blind interventional randomized controlled trial |
| Secondary study design | |
| Participant information sheet | 48375 PIS ALLEGATO 1-Foglio informativo per la partecipazione allo studio clinico.pdf |
| Scientific title | Assessing the Impact on dental biofilm of Heyndrickxia coagulans administered through sugar-free chewing gum: a double-blind randomized controlled trial |
| Study objectives | The present randomized controlled trial aims to evaluate the ability of the probiotic H. coagulans, administered through sugar-free chewing gum, to modified dental biofilm |
| Ethics approval(s) |
Approved 13/02/2024, Ethics Committee of the University of Milan (Via Festa del Perdono, 7, Milan, 20121, Italy; +39 2 5032 5032; comitato.etico@unimi.it), ref: 24/24 |
| Health condition(s) or problem(s) studied | Change in dental plaque microflora after administration of probiotics in healthy adult patients |
| Intervention | Participants will be randomized into two groups using a computer-generated randomization system. Both participants and investigators will be blinded to group allocation. All study participants will give their written consent to participate. The study will last a total of seven weeks. All enrolled subjects will receive instructions for at-home oral hygiene, along with a manual toothbrush and a fluoride toothpaste (1450 ppm F) to be used throughout the study period. Participants will be instructed not to use any mouthwash or other oral hygiene products aside from those provided during the experimental phase. Additionally, subjects will be asked to refrain from using antibacterial or antibiotic medications (either topical or systemic), from taking probiotics, and from consuming chewing gum or other products containing xylitol. Should the use of any of these products become necessary, participants will be required to notify the investigators and will subsequently be excluded from the study sample. Subjects in the intervention arm will be administered a chewing gum containing 5 × 10⁸ CFU of Heyndrickxia coagulans SNZ1969®; subjects in the control arm will receive a placebo chewing gum, identical in appearance and composition to that of the intervention group but without the probiotic. The experimental period will be structured as follows: an initial two-week washout phase, followed by a four-week Intervention phase, and concluding with a one-week post-Intervention phase. During the four-week Intervention, participants will be instructed to consume the assigned chewing gum five times per day (after breakfast, mid-morning, after lunch, mid-afternoon, and in the evening after dinner), at least 30 minutes after brushing their teeth. Follow-up assessments will be conducted at the following time points: after the initial two-week washout period (T0), after two weeks of chewing gum use (T1), after four weeks of chewing gum use (T2), and at the end of the post-Intervention period (T3). |
| Intervention type | Supplement |
| Primary outcome measure(s) |
The composition of the dental plaque microbial ecosystem is measured using metataxonomic analysis of 16S rRNA gene sequencing at T0, T2, and T3 |
| Key secondary outcome measure(s) |
1. Presence and quantity of *H. coagulans* SNZ1969® in dental plaque is measured using strain-specific qPCR at T0, T1, T2, and T3 in the intervention arm, and at T0 only in the control arm |
| Completion date | 10/04/2025 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 64 Years |
| Sex | All |
| Target sample size at registration | 40 |
| Total final enrolment | 56 |
| Key inclusion criteria | 1. Adult subjects aged 18 to 64 years 2. At least 24 natural teeth (excluding third molars) 3. Gingival index and plaque index scores ≤ 2 4. Stimulated salivary flow rate between 1.5 and 2.0 mL/min. |
| Key exclusion criteria | 1. Presence of systemic diseases 2. Pregnancy or lactation 3. History of drug abuse 4. Smoking habits 5. Use of fixed orthodontic appliances 6. Allergies to any ingredients in the chewing gums used |
| Date of first enrolment | 01/09/2024 |
| Date of final enrolment | 30/09/2024 |
Locations
Countries of recruitment
- Italy
Study participating centres
Milan
20121
Italy
Lainate (MI)
20045
Italy
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Stored in publicly available repository |
| IPD sharing plan | The datasets generated during and/or analysed during the current study will be stored in a publicly available repository https://doi.org/10.13130/RD_UNIMI/VATL7W (link to be activated once data is added) |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | First participant info sheet. In Italian | 05/11/2025 | No | Yes | |
| Participant information sheet | Second participant info sheet. In Italian | 05/11/2025 | No | Yes | |
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Additional files
- 48375 PIS ALLEGATO 1-Foglio informativo per la partecipazione allo studio clinico.pdf
- First participant info sheet. In Italian
- 48375 ALLEGATO 2-Informativa al trattamento dei dati personali.pdf
- Second participant info sheet. In Italian
Editorial Notes
04/11/2025: Trial's existence confirmed by Ethics Committee of the University of Milan.
