Tooth decay is one of the most common chronic diseases worldwide. Despite modern dental care products and widespread education, according to the World Health Organization (WHO), approximately 60–90% of schoolchildren and almost all adults suffer from tooth decay at some point in their lives. While conventional treatment focuses primarily on eliminating the damage caused by tooth decay, the modern approach goes a step further: It addresses the root causes—particularly by specifically promoting a healthy oral microbiome. In this context, probiotics such as Streptococcus salivarius M18 are becoming the focus of research.
What is caries and how does it develop?
Caries—also known as tooth decay—is caused by the interaction of bacteria, sugar, tooth surfaces, and time. The disease begins at the microscopic level and can develop over months or years. The key factor is an imbalance in the oral microbiome, the bacterial community in our mouth.
Certain bacteria, particularly Streptococcus mutans , are capable of converting sugar into acids. These acids attack tooth enamel and remove minerals such as calcium and phosphate—a process known as demineralization. If left unchecked, this process leads to cavities in the enamel that can extend into the interior of the tooth.
Classic caries treatment: drills, fillings, etc.
If caries has already caused visible damage to the teeth, often the only option is to visit a dentist. Traditional treatment involves several steps:
-
Diagnosis : The extent of the caries is determined by visual inspection, X-ray or laser fluorescence.
-
Removal of the carious substance : The dentist removes the affected tooth substance using a drill or laser.
-
Reconstruction : The resulting defect is closed with a filling made of composite, ceramic or amalgam.
-
Prevention : Recommendations on dental care, diet and regular check-ups help to prevent new cavities.
As effective as these methods are, they primarily combat the symptoms—the "hole in the tooth." The underlying causes, such as a disturbed bacterial balance, often go unnoticed.
The modern view: Caries as a microbial imbalance
New scientific findings show that caries is not a purely mechanical disease, but a biofilm-associated phenomenon. The biofilm—better known as plaque—consists of billions of microorganisms. As long as the bacterial balance is correct, the biofilm is harmless or even beneficial. However, an excess of acid-forming bacteria can endanger dental health.
This paradigm shift has paved the way for new strategies that address not only the symptoms but also the causes of caries. One of these innovative strategies is the use of oral probiotics .
Probiotics in the mouth: bacteria against bacteria?
Probiotics are primarily known in the field of intestinal health. These are live microorganisms that, when consumed in sufficient quantities, have a health benefit for the host. However, probiotics can also be beneficial in the mouth. Certain bacterial strains help stabilize the oral microbiome, suppress pathogens, and reduce inflammation.
A promising representative of this new generation of “good bacteria” is Streptococcus salivarius M18.
Streptococcus salivarius M18: A natural ally in the fight against caries
S. salivarius is a natural inhabitant of the human oral cavity—particularly in healthy individuals with a low predisposition to caries. The M18 strain has been isolated and intensively researched due to its specific anticariogenic properties.
What makes S. salivarius M18 so special?
Production of enzymes that break down plaque
The M18 strain produces enzymes called dextranase and urease. These help dissolve bacterial biofilm and neutralize the pH in the mouth. A neutral or alkaline pH is crucial for enabling remineralization of tooth enamel and inhibiting the growth of acid-loving caries bacteria.
Formation of bacteriocins
These antimicrobial peptides target harmful bacteria such as Streptococcus mutans without disrupting the entire oral microbiome. This is a major advantage over broad-spectrum antiseptics or antibiotics, which also kill beneficial bacteria.
Colonization and protective effect
Regular use of S. salivarius M18—e.g., in the form of lozenges—can lead to the strain permanently colonizing the oral cavity. This creates a kind of natural protective shield against caries-causing microorganisms.
Scientifically proven effect
Several studies, including those from New Zealand and Italy, have shown that subjects who took M18 for several weeks had significantly less plaque, lower levels of S. mutans , and improved pH values. There are also initial indications of a reduction in caries incidence.
Application in practice: How to use S. salivarius M18?
Probiotics for oral health are available in various forms, the most common being:
-
Lozenges : These are particularly suitable because contact with the oral mucosa lasts longer – ideal for colonization.
-
Mouthwashes with probiotics : These are less common but also effective.
-
Chewing gum or powder : They offer an interesting alternative for children or people with swallowing difficulties.
Ideally, use daily for at least two to four weeks, preferably in the evening after brushing your teeth. This gives the probiotic bacteria time to establish themselves in the oral cavity.
Complementary strategies for caries prevention
While probiotics like S. salivarius M18 can be a real game changer in caries prevention, they are no substitute for basic oral hygiene. A holistic approach includes:
-
Brush your teeth twice a day with fluoride toothpaste.
-
Dental floss or interdental brushes to keep the spaces between your teeth clean.
-
Low-sugar diet , especially avoiding frequent snacking and sugary drinks.
-
Regular check-ups with the dentist , at least twice a year.
-
Promote saliva flow , for example by drinking enough or chewing sugar-free gum – saliva has a natural protective function against tooth decay.
In combination with these measures, probiotics can help to keep the microbiome permanently in balance, which gives caries no chance.
Caries treatment in transition: From repair to prevention
What we are currently experiencing is a shift in dentistry – away from purely repair medicine toward preventative, microbiome-oriented care. Probiotics such as Streptococcus salivarius M18 symbolize this paradigm shift. They don't intervene only after damage has occurred, but rather support the natural balance in the mouth – gently, effectively, and without side effects.
This can make a decisive difference, especially for children, seniors, and people with limited oral hygiene skills. Health-conscious adults also benefit from the combination of modern dentistry and probiotic prevention.
Conclusion: Fight caries with a healthy bacterial balance
The days when the fight against tooth decay was waged exclusively with toothbrushes and drills are coming to an end. Today we know: the key lies in a stable oral microbiome. Probiotics—especially Streptococcus salivarius M18—offer a promising way to promote this balance naturally.
Therefore, anyone who wants to stay caries-free in the long term should not only pay attention to good dental care, but also consider how to strengthen their oral microbiome. Probiotic lozenges could soon be as commonplace as toothpaste and floss.
