Efficacy of SALI-10 Oral Probiotics in Experimental Gingivitis

A Randomized, Double-Blind, Placebo-Controlled Study to Determine the Efficacy SALI-10 Oral Probiotics in Experimental Gingivitis

Gingivitis is among the most prevalent oral diseases worldwide, affecting an estimated 50-90% of adults. It is a reversible condition primarily caused by microbial plaque accumulation on teeth and gingival surfaces, which triggers inflammation. Standard care emphasizes plaque reduction through oral hygiene, and research shows gingivitis can be reversed once hygiene resumes. The classic experimental gingivitis (EG) model developed in 1965 by Löe and Silness demonstrated the direct link between plaque buildup and gingival inflammation, further confirming that gingival health can be restored after resuming proper care.

Microbial ecology shifts are central to gingivitis pathogenesis. In health, the oral microbiome is dominated by gram-positive Streptococcus species. With plaque accumulation, microbial communities transition to gram-negative periopathogens such as Porphyromonas, Tannerella, Treponema, and Prevotella. This dysbiosis provokes heightened inflammation, tissue damage, and, in susceptible individuals, progression to periodontitis. Individual variability in the inflammatory response has been associated with differences in the presence and activity of beneficial streptococci. Certain strains of Streptococcus salivarius produce lantibiotics called salivaricins-polycyclic antimicrobial peptides containing lanthionine residues. Salivaricins inhibit oral pathogens and have been investigated for their antimicrobial and probiotic properties, particularly in the context of rising antibiotic resistance. Probiotic S. salivarius strains isolated from healthy individuals have demonstrated safety and antimicrobial potential in previous studies, supporting their use in preventing oral and respiratory infections.

A strain of S. salivarius designated SALI-10 produces a lantibiotic, Salivaricin 10, and is being evaluated as a candidate for gingivitis prevention. This strain is hypothesized to (1) help stabilize populations of beneficial streptococci during plaque accumulation, (2) competitively inhibit periopathogens such as Porphyromonas and Prevotella, and (3) suppress the dysbiotic shift toward gram-negative dominance. By contributing to microbial balance and reducing inflammatory triggers, SALI-10 may support resilient host-microbe interactions associated with gingival health. This approach may offer a dual antimicrobial and microbiome-stabilizing strategy with relevance to gingivitis management and longer-term periodontal health.

Study Overview

• Status: Recruiting
• Conditions: Gingivitis
• Intervention / Treatment: Dietary supplement: 6B SALI-10

Detailed Description

Gingivitis is an oral disease condition affecting 50% to 90% of adults globally. The gingivitis pathology can be reversed by reduction or removal of microbial plaque that accumulates on hard and soft tissues and is considered standard of care in the industry. Regular oral hygiene in combination with therapeutics that delivers an anti-microbial benefit is thought to mitigate the onset of gingivitis. However, testing therapeutics for prophylaxis benefit to mitigate development of gingivitis has not been fully examined.

The classical model of experimental gingivitis (EG) was developed in 1965 by Loe and Silness who convincingly demonstrated the causative relationship between the accumulation of dental plaque and the development of clinically evident gingivitis in healthy young adults abstaining from all oral hygiene practices for a 21-day period. Furthermore, on resuming customary oral hygiene practices, all subjects demonstrated a return to gingival health. Understanding how participants returned quickly to gingival health aligns with the current understanding that the clinically healthy state is an active and dynamic process.

Neutrophils, a type of white blood cell (leukocyte), represent a key component of the innate defence system that protects periodontal tissue from both gingivitis and periodontitis. Not only are they the first line of cellular defence, but they are among the most abundant leukocytes within the periodontal tissues. Gingivitis is associated with a significant increase in the number of neutrophils that migrate to periodontal tissue. In contrast, individuals with too few neutrophils brought about by either congenital deficiencies in neutrophil numbers or transit (LAD 1 and 2), or those with induced neutropenia by chemical induction with antimitotic agents such as cyclophosphamide, invariably develop periodontitis. Likewise, studies in knockout mice that are defective in neutrophil transit also develop periodontitis. Consistent with the key contribution of neutrophils to both gingivitis and periodontitis, neutrophil transit to gingival tissue is highly regulated. The periodontium contains innate host defense mediators that facilitate the transit of neutrophils from the highly vascularized gingival tissue to the gingival crevice, where they form a "wall" between the host tissue and the dental plaque biofilm.

However, the prolonged presence of neutrophils in gingival tissue is not tolerated in the healthy state. The failure to downregulate neutrophil transit results in an increase in neutrophil numbers in gingival tissue and a significant increase in periodontal bone loss. Therefore, neutrophil homing to the gingival crevice is highly regulated such that under conditions of periodontal health the appropriate amount of neutrophils are present to maintain control of dental plaque bacterial growth and yet not elicit tissue damage. Evaluation of oral and blood neutrophils during experimental gingivitis has shown that people with uniquely high inflammatory response have an exaggerated polymorphonuclear neutrophil response both in the oral cavity and in the blood.

Gingivitis is a reversible inflammatory condition caused by the accumulation of dental plaque and the associated disruption of the host-microbial homeostasis. During gingivitis, the microbial community transitions from being dominated by gram-positive health-associated bacteria, such as Streptococcus species, to gram-negative periopathogens, including species of the genera Porphyromonas, Tannerella, Treponema and Prevotella. This dysbiotic shift triggers inflammatory responses, leading to tissue damage and, in some cases, progression to periodontitis.

A recent study on human experimental gingivitis identified three distinct host response phenotypes-high, low, and slow responders-based on clinical, inflammatory, and microbial parameters:

High Responders: Rapid plaque accumulation accompanied by a significant increase in gram-negative periopathogens and elevated inflammatory markers, such as interleukin-1β (IL-1β).

Low Responders: Similar plaque accumulation to high responders but lower inflammation, suggesting a more muted host response to bacterial dysbiosis.

Slow Responders: Delayed plaque accumulation and microbial succession, with prolonged dominance of health-associated Streptococcus species and a delayed or reduced inflammatory response.

Microbial analysis revealed that the persistence of beneficial Streptococcus species, such as S. sanguinis and S. oralis, in slow and low responders correlates with a protective effect against the emergence of periopathogens and the associated inflammatory cascade. Conversely, the loss of these beneficial bacteria in high responders was linked to more severe inflammation, highlighting the critical role of the oral microbiome in modulating gingivitis severity.

Lantibiotic salivaricins are polycyclic peptides containing lanthionine and/or β-methyllanthionine residues that are produced by certain strains of Streptococcus salivarius, which almost exclusively reside in the human oral cavity. These molecules are notable for their antimicrobial activity toward relevant oral pathogens, supporting the development of salivaricin-producing probiotic strains. Salivaricins are also relevant for development of novel antibacterial therapies in the context of emerging antibiotic resistance. Previous work has shown the bacteriocin and safety features of S. salivarius strains isolated from healthy subjects, demonstrating their potential for use as probiotics.

Proposed Solution: S. salivarius SALI-10

The investigators propose using a novel strain, Streptococcus salivarius SALI-10, as a targeted microbial intervention to modulate the oral microbiome and prevent gingivitis. S. salivarius SALI-10 is hypothesized to:

• Maintain a stable population of beneficial streptococci during plaque accumulation.
• Inhibit the growth of periopathogens through microbial competition and production of Salivaricin 10.
• Delay or suppress the dysbiotic shift to gram-negative dominance, thereby reducing the inflammatory response.

By supporting microbial homeostasis, SALI-10 may emulate the resilience observed in slow responders and offer a novel strategy for gingivitis prevention.

Dosage Regimen

This is a placebo-controlled study. Each participant randomized to the intervention group will receive mint-flavoured SALI-10 lozenges. They will take one lozenge twice a day-morning and evening-after brushing, allowing it to dissolve in the mouth. Participants will use the study lozenges throughout the study.

Prestudy Screening and Baseline Evaluation Telephone Pre-Screening

Potential study participants who express interest will be contacted by telephone. Eligibility for screening will be assessed using standard recruitment questions.

In-Person Screening

Before screening procedures occur, participants will provide informed consent. Participants will complete demographic and health information and undergo an oral examination of soft and hard tissues. Female participants will undergo a urine pregnancy test. The screening continues until sixty (60) participants are enrolled.

Visit 1 - Baseline Assessment

Participants will undergo an oral exam including probing depth (PD), attachment level (AL), visible plaque index (VPI), gingival index (GI), and bleeding on probing (BOP). Biospecimens collected will include gingival crevicular fluid (GCF), subgingival plaque, saliva, and an oral rinse. Participants will receive a dental cleaning and their assigned study product with instructions.

Treatment Visit Schedule

Participants will consume two lozenges per day at home and attend eight (8) study visits.

Visit 2 (Day -14 / -7)

Oral examination and biospecimen collection (GCF, plaque, saliva, oral rinse). Participants report use of NHPs and adverse effects.

Induction Phase (No Oral Hygiene for 21 Days) Visit 3 (Day 0)

Oral examination and biospecimen collection. Participants refrain from all oral hygiene for 21 days and continue their assigned lozenges.

Visit 4 (Day 7)

Oral examination and biospecimen collection. Participants are reminded to continue refraining from oral hygiene.

Visit 5 (Day 14)

Oral examination and biospecimen collection. Participants continue refraining from oral hygiene.

Resolution Phase (Participants Resume Oral Hygiene) Visit 6 (Day 21)

Oral examination and biospecimen collection. Participants receive a dental cleaning and resume home oral hygiene while continuing study lozenges.

Visit 7 (Day 28)

Oral examination and biospecimen collection.

Visit 8 - End of Study (Day 35)

Oral examination and biospecimen collection. Participants receive compensation and resume regular oral hygiene. After study completion, the manufacturer will unblind the product groups, and participants will be informed of their assignment.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Mark Kwiecinski, P.Eng, M.Sc Physics; Phone Number: 1-613-513-4413; Email: Mark@PMKengineeing.com

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G 1G5
      • Recruiting
      • University of Toronto
      • Contact: Dr. Michael Goldberg, MDM; Phone Number: 1 (416) 864-8215; Email: M.Goldberg@dentistry.utoronto.ca
      • Principal Investigator: Dr. Michael Goldberg, MDM

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Male or female volunteers aged 18-70 years
2. In good general health, ASA I
3. No clinical signs of gingival inflammation at >90% of sites observed
4. Absence of Periodontal Pockets, Probing Depth (PD) < 3.0 mm on all teeth/site
5. Absence of Clinical Attachment Loss (CAL) = 0 mm
6. No periodontal disease history
7. Have at least 20 gradeable teeth
8. Non-smokers
9. Fluent in English
10. For study participants of childbearing potential, both men and women, at least one of the following birth control measures must be used: abstinence, hormonal birth control (oral, injectable, transdermal, intra-vaginal), intrauterine devices, confirmed successful vasectomy, or condoms.

Exclusion Criteria:

1. Presence of orthodontic bands.
2. Presence of partial or full dentures.
3. Tumour(s) of the soft or the hard tissues of the oral cavity.
4. Cavitated carious lesions requiring immediate restorative treatment.
5. History of allergy to a consumer or personal care products or dentifrice ingredients as determined by the dental profession monitoring the study.
6. Participation in any other clinical study or test panel within one month before entering the study.
7. Medical condition which requires pre-medication before dental visits/procedures
8. Current use of anti-inflammatory, antibiotics, or antimicrobial drugs or within the last 30 days of enrolment.
9. History of periodontal disease.
10. History of systemic inflammatory, immune conditions and immunocompromised conditions
11. Pregnant or nursing women or those planning to get pregnant
12. Use of tobacco products.
13. Long-term antibiotic or anti-inflammatory therapy.
14. Medication or Natural Health Products (NHPs) that could affect the gingiva like calcium channel blockers, anti-epileptic therapy etc.
15. Medical condition or any current usage of medication that the investigator considers may compromise the study participant's safety as well as the quality of the study results
16. Allergy to any of the following ingredients: Streptococcus Salivarius, Sorbitol, Isomalt, Calcium phosphate dibasic, Potato starch, Mint, Glyceryl dibehenate, Stevia, Maltodextrin
17. Use of other probiotics
18. Taking anticoagulant medications and those suffering from blood and bleeding disorders
19. Recently experienced or will be experiencing dental, oral or any type of surgery.
20. Use of anti-plaque/ anti-gingivitis products
21. Presence of active infections
22. Participants who are experiencing nausea, fever, vomiting, bloody diarrhoea or severe abdominal pain.
23. Use of any antibiotics.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Placebo; Placebo lozenges used
Active Comparator: SALI-10; Lozenges containing 6B CFUs of	Dietary supplement: 6B SALI-10; Lozenges containing 6B CFUs of probiotic S. salivarius SALI-10

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean change in percentage of sites with bleeding on probing (BOP)	Bleeding on probing (BOP) will be assessed at six sites per tooth using a UNC-15 periodontal probe. The proportion of bleeding sites (% of total sites) will be calculated for each participant. Group mean ± SD change from baseline will be reported. Scale: 0-100 %; lower values = less gingival inflammation.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in oral neutrophil (oPMN) count per 10 mL unstimulated saliva	Unstimulated saliva (10 mL) will be collected, centrifuged, and stained with acridine orange. Neutrophils will be counted using fluorescence microscopy and a hemocytometer. Results expressed as total PMNs × 10³ cells / 10 mL.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).
Change in concentration of cytokines (IL-1β, IL-6, MMP-8) in gingival crevicular fluid (pg/mL)	Gingival crevicular fluid (GCF) will be collected using Periopaper strips and analyzed with bead-based multiplex immunoassays (Luminex). Mean concentrations (pg/mL) will be reported per participant; lower values indicate reduced local inflammation.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).
Change in relative abundance of periodontal and commensal bacteria measured by quantitative PCR and shotgun metagenomics	DNA extracted from subgingival plaque and tongue swabs will be analyzed for P. gingivalis, F. nucleatum, T. forsythia, P. micra and S. salivarius SALI-10. Abundance expressed as ΔCt relative to total 16S rRNA gene copies. Metagenomic analysis will evaluate community shifts.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).
Change in concentration of volatile sulfur compounds (VSCs) in exhaled air measured by Halimeter (ppb)	Halitosis will be quantified using a calibrated Halimeter (Interscan Corp.). Three consecutive breath readings will be averaged per visit. Results reported in parts per billion (ppb); lower values indicate improved oral odor.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).
Change in mean Gingival Index (GI) score	Gingival inflammation will be assessed using the Löe-Silness Gingival Index. Scale: 0 = normal; 1 = mild; 2 = moderate; 3 = severe. Lower mean scores indicate improved gingival health.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).
Change in mean Plaque Index (PI) score	Plaque accumulation will be assessed using the Silness-Löe Plaque Index. Scale: 0 = no plaque; 1 = thin film; 2 = moderate deposits; 3 = abundant plaque. Lower mean scores indicate improved oral hygiene.	Baseline; Weeks 1 and 2 (pre-induction); Weeks 3 - 5 (induction phase - no-brushing); Weeks 6 and 7 (resolution phase).

Collaborators and Investigators

• Sponsor: Ostia Sciences
• Collaborators: University of Toronto
• Investigators: Principal Investigator: Dr. Michael Goldberg, MDM, University of Toronto

Publications and helpful links

General Publications

• LOE H, THEILADE E, JENSEN SB. EXPERIMENTAL GINGIVITIS IN MAN. J Periodontol (1930). 1965 May-Jun;36:177-87. doi: 10.1902/jop.1965.36.3.177. No abstract available.
• Albandar JM, Rams TE. Global epidemiology of periodontal diseases: an overview. Periodontol 2000. 2002;29:7-10. doi: 10.1034/j.1600-0757.2002.290101.x. No abstract available.
• van der Weijden F, Slot DE. Oral hygiene in the prevention of periodontal diseases: the evidence. Periodontol 2000. 2011 Feb;55(1):104-23. doi: 10.1111/j.1600-0757.2009.00337.x. No abstract available.
• Wellappuli NC, Fine N, Lawrence HP, Goldberg M, Tenenbaum HC, Glogauer M. Oral and Blood Neutrophil Activation States during Experimental Gingivitis. JDR Clin Trans Res. 2018 Jan;3(1):65-75. doi: 10.1177/2380084417742120. Epub 2017 Nov 20.
• Kerns KA, Bamashmous S, Hendrickson EL, Kotsakis GA, Leroux BG, Daubert DD, Roberts FA, Chen D, Trivedi HM, Darveau RP, McLean JS. Localized microbially induced inflammation influences distant healthy tissues in the human oral cavity. Proc Natl Acad Sci U S A. 2023 Oct 10;120(41):e2306020120. doi: 10.1073/pnas.2306020120. Epub 2023 Oct 2.
• Gunsolley JC. A meta-analysis of six-month studies of antiplaque and antigingivitis agents. J Am Dent Assoc. 2006 Dec;137(12):1649-57. doi: 10.14219/jada.archive.2006.0110.
• Gallagher H, Ramsay SC, Barnes J, Maggs J, Cassidy N, Ketheesan N. Neutrophil labeling with [(99m)Tc]-technetium stannous colloid is complement receptor 3-mediated and increases the neutrophil priming response to lipopolysaccharide. Nucl Med Biol. 2006 Apr;33(3):433-9. doi: 10.1016/j.nucmedbio.2005.12.014. Epub 2006 Mar 9.
• Berezow AB, Darveau RP. Microbial shift and periodontitis. Periodontol 2000. 2011 Feb;55(1):36-47. doi: 10.1111/j.1600-0757.2010.00350.x. No abstract available.
• Barbour A, Wescombe P, Smith L. Evolution of Lantibiotic Salivaricins: New Weapons to Fight Infectious Diseases. Trends Microbiol. 2020 Jul;28(7):578-593. doi: 10.1016/j.tim.2020.03.001. Epub 2020 Apr 6.
• Barbour A, Philip K. Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects. PLoS One. 2014 Jun 18;9(6):e100541. doi: 10.1371/journal.pone.0100541. eCollection 2014.

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2025
• Primary Completion (Estimated): December 31, 2025
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: September 23, 2025
• First Submitted That Met QC Criteria: November 25, 2025
• First Posted (Actual): December 1, 2025

Study Record Updates

• Last Update Posted (Actual): December 1, 2025
• Last Update Submitted That Met QC Criteria: November 25, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Probiotic; Oral Health; Lozenge
• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Infections; Gingival Diseases; Gingivitis
• Other Study ID Numbers: OstiaGingivitis

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No individual participant data (IPD) will be shared. IPD will not be shared because the data include proprietary early-stage clinical development information that is not intended for public release.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No