Researchers reviewed 12 studies to see if probiotics—the “good bacteria” found in some foods and supplements—could help prevent cavities in children and teenagers. They found that certain types of probiotics, especially ones called Lactobacillus rhamnosus and L. paracasei, may help reduce cavities when taken for 6-10 months. However, the evidence isn’t super strong yet, and different probiotic types seem to work differently. While probiotics show promise as an extra tool alongside regular brushing and flossing, they shouldn’t replace your normal dental care routine.

The Quick Take

  • What they studied: Whether taking probiotic supplements could help prevent cavities in children and teenagers by reducing the harmful bacteria that cause tooth decay
  • Who participated: The review looked at 12 different research studies involving children and teenagers of various ages. The studies compared kids who took probiotics to kids who didn’t take them
  • Key finding: Certain probiotics (Lactobacillus rhamnosus SP1 and L. paracasei SD1) taken for 6-10 months appeared to reduce cavities and decrease cavity-causing bacteria in the mouth compared to kids who didn’t take them
  • What it means for you: Probiotics may be a helpful extra tool for cavity prevention, especially for kids at high risk of cavities, but they work best alongside brushing, flossing, and limiting sugary foods. They’re not a replacement for regular dental care

The Research Details

This was a systematic review, which means researchers looked at all the best quality studies they could find on this topic and combined the results. They searched five major medical databases for studies published up to early 2026. They only included studies where some kids got probiotics and others got a fake treatment (placebo) so they could fairly compare the results.

The researchers carefully checked each study to make sure it was done well. They looked at whether the studies measured the same things, used the same types of probiotics, and gave them in the same way. Because the studies were quite different from each other, the researchers couldn’t combine all the numbers together—instead, they described what each study found.

They measured things like how many new cavities formed, whether existing cavities got worse or better, and how many cavity-causing bacteria were in kids’ mouths.

This approach is important because it gathers all the best evidence available instead of relying on just one study. By looking at multiple studies together, researchers can see if the results are consistent and whether probiotics really work. The fact that they focused on different probiotic strains (types) is important because not all probiotics are the same—some might work better than others for cavity prevention.

The researchers used strict rules to decide which studies to include, which makes the results more trustworthy. They checked each study carefully for problems that might make the results unreliable. However, because the studies used different types of probiotics, different amounts, different ways of giving them (milk, tablets, etc.), and measured results differently, it’s harder to say for certain that probiotics work. The researchers rated the overall strength of evidence as moderate for preventing new cavities but low for other outcomes, meaning we should be somewhat confident but not completely certain

What the Results Show

The main finding was that certain probiotics did appear to help prevent cavities. Specifically, Lactobacillus rhamnosus SP1 and L. paracasei SD1 reduced the number of new cavities that formed when kids took them for 6-10 months. These probiotics also reduced the amount of Streptococcus mutans—the main bacteria that causes cavities—in kids’ mouths.

The probiotics seemed to work best when given through milk or tablets rather than other methods. The effect was noticeable but modest, meaning probiotics helped but weren’t a miracle cure. The benefits were strongest in children and teenagers who were already at high risk for cavities, such as those with poor oral hygiene or high sugar diets.

However, the results weren’t the same across all studies. Some studies showed bigger benefits than others, and some probiotic strains worked better than others. This variation suggests that the type of probiotic matters a lot.

The review also looked at whether probiotics could help with secondary prevention—stopping cavities from coming back or helping white spot lesions (early cavity signs on teeth with braces) go away. The evidence for these outcomes was much weaker and inconsistent. Some studies showed small benefits, but others showed no benefit at all. This means we can’t confidently say that probiotics help prevent cavities from returning or help fix early cavity damage

This research fits with what scientists already knew about how probiotics work in the mouth. Previous research suggested that certain good bacteria might compete with cavity-causing bacteria and produce substances that protect teeth. This review confirms that idea has some merit, but it also shows that the effect is smaller and more complicated than originally hoped. The findings suggest probiotics are a supplement to regular dental care, not a replacement

Several important limitations exist. First, the studies looked at were quite different from each other—they used different probiotic types, different amounts, different delivery methods, and measured results in different ways. This makes it hard to say exactly which probiotics work best. Second, most studies were relatively short (6-10 months), so we don’t know if benefits last longer. Third, some studies had small numbers of participants, which makes results less reliable. Finally, the researchers couldn’t combine all the data into one big analysis, so they had to describe results separately, which is less powerful than combining everything together

The Bottom Line

Based on moderate evidence, probiotics may be considered as an additional tool for cavity prevention in children and teenagers at high risk for cavities, but only alongside regular brushing, flossing, and limiting sugary foods. Specific strains like Lactobacillus rhamnosus and L. paracasei appear more promising than others. Talk to your dentist before starting probiotics, as they’re not proven to work for everyone. Confidence level: Moderate for primary cavity prevention, Low for preventing cavity recurrence

Kids and teenagers with a history of cavities, poor oral hygiene, or high sugar intake might benefit most from probiotics. Children with braces or other orthodontic work should not expect probiotics to prevent white spot lesions based on current evidence. Probiotics are probably not necessary for kids with excellent oral hygiene and low cavity risk. Anyone considering probiotics should discuss it with their dentist first

Based on the studies reviewed, you’d need to take probiotics consistently for at least 6-10 months to see potential cavity-prevention benefits. This isn’t a quick fix—it’s a long-term strategy. Even then, the benefits are modest, meaning you might see fewer cavities but not zero cavities. Results may vary depending on the specific probiotic strain used

Want to Apply This Research?

  • Track daily probiotic intake (yes/no) and pair it with daily brushing and flossing frequency. Monitor cavity-related symptoms like tooth sensitivity or visible spots on teeth, and note any changes at dental checkups every 6 months
  • Set a daily reminder to take your probiotic supplement at the same time each day (morning or with a meal works well). Link this habit to an existing routine like breakfast or bedtime to make it easier to remember consistently
  • Keep a 6-month log of oral health habits including probiotic use, brushing frequency, flossing, and sugar intake. Share results with your dentist at regular checkups to see if cavity rates are improving. Track any changes in tooth sensitivity or visible white spots

This review summarizes research on probiotics for cavity prevention but should not replace professional dental advice. Probiotics are not proven to prevent all cavities and should only be used as an additional tool alongside regular brushing, flossing, and professional dental care. Always consult with your dentist or pediatrician before starting any probiotic supplement, especially for children. Individual results may vary based on the specific probiotic strain, dosage, and personal oral health habits. This information is current as of February 2026 and may change as new research emerges.