Probiotic Defense Against Gum Disease
September 2025 Issue

Probiotic Defense Against Gum Disease

Clinical data show that a targeted probiotic inhibited harmful oral bacteria, and reduced gum bleeding and plaque buildup.

Scientifically reviewed by: Gary Gonzalez, MD, in August 2025. Written by: Marsha McCulloch, MS, RD.

In a study of 794 adults, 82% of those who reported gingival bleeding believed it to be a harmless condition.1

Bleeding gums, however, are a common sign of periodontal disease, which can damage the tissues that anchor teeth in place.2,3

Even more worrisome, periodontal infections may increase the risk of non-oral conditions, including diabetes, heart disease, and dementia.4

A key driver of periodontal disease is an imbalance of microbes in the mouth that promote harmful bacteria and the buildup of dental plaque.2,4

Plaque can result in gaps between the teeth and gums, called periodontal pockets, which can become infected and inflamed.2

Scientists have identified a specific probiotic strain that helps keep problematic oral bacteria in check. It has been clinically shown to reduce gum bleeding and inflammation by 31% when taken daily.5,6

Researchers have also developed a heat-treated bacteria, a postbiotic, that in a clinical trial reduced periodontal pocket depth 64% better than the placebo group.7

Taking this probiotic and postbiotic daily in addition to brushing and flossing may provide a strong defense against periodontal disease.

Microbiome of the Mouth

The link between periodontal disease and other conditions may be driven by chronic inflammation, immune dysregulation, and the spread of harmful bacteria from the mouth to other parts of the body.2

The oral microbiome includes beneficial bacteria like Streptococcus salivarius (S. salivarius) as well as harmful bacteria like Streptococcus mutans (S. mutans).16

S. mutans is one of the top promoters of tooth decay. This bacteria thrives in an acidic (low pH) oral environment.16

In the mouth, S. mutans ferments sugars from food and produces acid that can erode tooth enamel. This promotes the buildup of plaque on teeth, which can lead to tooth decay and periodontal disease.16

Improving the Oral Ecosystem

The M18 strain of S. salivarius can provide a robust defense against S. mutans.

In a clinical trial involving 69 young adults aged 18–40 at high risk for tooth decay, 22 participants took a nightly lozenge containing S. salivarius M18 (2.5 billion CFU) after brushing.

After 30 days, the M18 group showed better oral health outcomes compared to those following standard oral care practices without the M18 probiotic.17

The M18 probiotic group experienced a 75% decrease in salivary levels of harmful S. mutans. In the control group, S. mutans decreased by only 11%.

The M18 probiotic group also had a 5.2% increase in salivary pH, meaning it was less acidic and better for oral health, while the control group’s saliva became slightly more acidic.17

Increased acidity can lead to an increase in dental problems because when the pH of the oral cavity becomes more acidic, S. mutans can become more competitive and damaging.16,18

Less Dental Plaque, Healthier Gums

In a randomized controlled clinical trial, 61 participants with gingivitis aged between 18 to 25 years were randomized to receive a daily Streptococcus salivarius  M18 (500 million CFU) lozenge or a placebo nightly after brushing, for four weeks. The probiotic improved gum health in young adults with gingivitis.5

Participants showed 31% reduced gingival inflammation index, and mild but significant improvement in dental plaque index compared to placebo after four weeks. Continued use of S. salivarius M18 might be needed to maintain results.

In another trial, a three-month supplementation with Streptococcus salivarius M18 has been shown to reduce gingival bleeding and dental plaque in young adults with gingivitis.6

In this longer randomized controlled trial, 62 individuals with gingivitis were randomized to receive S. salivarius M18 (500 million CFU) or a placebo every evening for three months followed by a four-week washout period.

The daily use led to significant improvements in gum health compared to placebo. The probiotic group had a 31% placebo-adjusted reduction in gum bleeding and a 7% reduction in dental plaque buildup.6

The best results for gum health and dental plaque control likely come from long-term use of the probiotic.

Postbiotic Improves Periodontal Pockets

As part of a routine checkup, dental staff may probe a person’s gums to check periodontal pockets. A pocket depth of 4 mm or more suggests periodontal disease.19

Scientists explored living oral probiotics and heat-treated postbiotics. Postbiotics include components of inactivated beneficial microbes.20

For a randomized controlled trial, researchers recruited 39 older adults with chronic periodontitis, including one or more periodontal pockets measuring at least 4 mm.7

Subjects took 50 mg of heat-treated L. plantarum L-137 (a postbiotic) or a placebo daily for 12 weeks. Both groups also underwent standard periodontal therapy.

The postbiotic group showed a 64% greater reduction in pocket depth than the placebo group.7

Previous studies have shown that heat-treated L. plantarum L-137 stimulates the action of IL-12, a cytokine (signaling molecule) that supports healthy immune function. The researchers suggest that this immune modulation may help promote oral health.7,21

Together, S. salivarius M18 and heat-treated L. plantarum L-137 may offer a balanced combination for optimizing periodontal health.

The Mouth-Body Connection

Periodontal disease (also called gum disease) starts with gingivitis, a condition characterized by red, swollen gums that bleed easily.2,8

This can progress to periodontitis, severe gum disease that includes deepening periodontal pockets. These pockets trap infection-causing bacteria and plaque between the teeth and gums.2,8

The body’s immune response to this microbial assault leads to inflammation and damage to the teeth’s structural support, potentially resulting in tooth removal.8,9

Damage caused by periodontal disease isn’t necessarily confined to the teeth. Cardiovascular disease, diabetes, and dementia are just a few of the non-oral conditions associated with periodontal disease.4,10-15

What You Need To Know

Banish the Bacteria Behind Gum Disease

  • Bleeding gums can be a sign of perio-dontal disease, which harms the gums and bones that support teeth. Periodontal disease is also linked to an increased risk of heart disease, diabetes, and dementia.
  • A major driver of periodontal disease is an overgrowth of harmful bacteria that promotes dental plaque buildup, inflammation, and destruction of oral tissues.
  • The probiotic Streptococcus salivarius M18 is clinically shown to counteract harmful oral bacteria, reducing gum inflammation and bleeding by 31%.
  • Heat-treated Lactobacillus plantarum L-137, a postbiotic, has been clinically shown to reduce periodontal pocket depth by 64% greater than seen in placebo group.
  • Daily oral intake of this probiotic-postbiotic combination can be a beneficial addition to dental care routines.

Summary

A balanced oral microbiome promotes periodontal health.

In clinical trials, the probiotic S. salivarius M18 inhibited the growth of harmful oral bacteria, reduced gum inflammation and bleeding, and helped prevent dental plaque buildup.

A heat-treated postbiotic, L. plantarum L-137, was clinically shown to reduce periodontal pockets.

Long-term use of this oral probiotic-postbiotic combination can help keep teeth and gums healthy, with benefits for overall health. n

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

References

  1. Baudet A, Veynachter T, Rousseau H, et al. Perception of Gingival Bleeding by People and Healthcare Professionals: A Multicentre Study in an Adult French Population. Int J Environ Res Public Health. 2020 Aug 18;17(16).
  2. Hashim NT, Babiker R, Padmanabhan V, et al. The Global Burden of Periodontal Disease: A Narrative Review on Unveiling Socioeconomic and Health Challenges. Int J Environ Res Public Health. 2025 Apr 16;22(4).
  3. Available at: https://www.nidcr.nih.gov/health-info/gum-disease. Accessed June 24, 2025.
  4. Available at: https://www.health.harvard.edu/heart-health/why-your-gums-are-so-important-to-your-health. Accessed June 24, 2025.
  5. Babina K, Salikhova D, Doroshina V, et al. Antigingivitis and Antiplaque Effects of Oral Probiotic Containing the Streptococcus salivarius M18 Strain: A Randomized Clinical Trial. Nutrients. 2023 Sep 6;15(18).
  6. Babina K, Salikhova D, Makeeva I, et al. A Three-Month Probiotic (the Streptococcus salivarius M18 Strain) Supplementation Decreases Gingival Bleeding and Plaque Accumulation: A Randomized Clinical Trial. Dent J (Basel). 2024 Jul 18;12(7).
  7. Iwasaki K, Maeda K, Hidaka K, et al. Daily Intake of Heat-killed Lactobacillus plantarum L-137 Decreases the Probing Depth in Patients Undergoing Supportive Periodontal Therapy. Oral Health Prev Dent. 2016;14(3):207-14.
  8. Kalhan AC, Wong ML, Allen F, et al. Periodontal disease and systemic health: An update for medical practitioners. Ann Acad Med Singap. 2022 Sep;51(9):567-74.
  9. Zhang M, Liu Y, Afzali H, et al. An update on periodontal inflammation and bone loss. Front Immunol. 2024;15:1385436.
  10. Sanz M, Marco Del Castillo A, Jepsen S, et al. Periodontitis and cardiovascular diseases: Consensus report. J Clin Periodontol. 2020 Mar;47(3):268-88.
  11. Munoz Aguilera E, Suvan J, Orlandi M, et al. Association Between Periodontitis and Blood Pressure Highlighted in Systemically Healthy Individuals: Results From a Nested Case-Control Study. Hypertension. 2021 May 5;77(5):1765-74.
  12. Paunica I, Giurgiu M, Dumitriu AS, et al. The Bidirectional Relationship between Periodontal Disease and Diabetes Mellitus-A Review. Diagnostics (Basel). 2023 Feb 11;13(4).
  13. Costa R, Rios-Carrasco B, Lopez-Jarana P, et al. Periodontal status and risk factors in patients with type 1 diabetes mellitus. Clin Oral Investig. 2025 Feb 5;29(2):113.
  14. Borsa L, Dubois M, Sacco G, et al. Analysis the Link between Periodontal Diseases and Alzheimer’s Disease: A Systematic Review. Int J Environ Res Public Health. 2021 Sep 3;18(17). 15. Lundergan W, Parthasarathy K, Knight N. Periodontitis and Alzheimer’s disease: is there a connection? Oral. 2024;4(1):61-73.
  15. Ye D, Liu Y, Li J, et al. Competitive dynamics and balance between Streptococcus mutans and commensal streptococci in oral microecology. Crit Rev Microbiol. 2025 May;51(3):532-43.
  16. Poorni S, MS N, Ramakrishnan Srinivasan M. Comparing the effect of probiotic Streptococcus salivarius K12 and M18 on the Streptococcus mutans count, salivary pH and buffer capacity: a randomized double blinded clnical trial. Cumhuriyet Dent J. 2021;24(4):346-54.
  17. Friedman JY. The role of Streptococcus mutans in the formation of dental caries: an ecological perspective. The Science Journal of the Lander College of Arts and Sciences. 2011;5(1).
  18. Lima de Sousa T, Dourado D, Rodrigues JS, et al. Treatment of periodontal disease: does drug delivery matter? Front Bioeng Biotechnol. 2024;12:1427758.
  19. Salminen S, Collado MC, Endo A, et al. The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nat Rev Gastroenterol Hepatol. 2021 Sep;18(9):649-67.
  20. Hirose Y, Murosaki S, Yamamoto Y, et al. Daily intake of heat-killed Lactobacillus plantarum L-137 augments acquired immunity in healthy adults. J Nutr. 2006 Dec;136(12):3069-73.