A patient came to me, Elena, 34. She said: «I brush 3 minutes twice a day, fluoride toothpaste, I almost never eat sweets. Why do I get a new filling every 6 months?» I examined her. I found 2 new cavities, both on contact surfaces, in the places a toothbrush can't reach. Her problem was not sloppy hygiene. It was that she had never used interdental brushes.
I see situations like this all the time. 16 years of practice have convinced me that caries is not about the brush. It is about the system: paste with the right fluoride, frequency of sugar, interdental cleaning, fluoride varnish, Fissurenversiegelung, xylitol, regular PZR. If you do only one thing, you are not preventing caries, you are getting lucky.
According to the Sixth German Oral Health Study (DMS 6, 2021-2023), adults aged 35-44 have an average DMFT score of 8.3. Those are teeth already affected by caries, filled, or extracted. That is almost half of the 1989 figure. Prevention works. But only when applied consistently. Here are my 7 rules that I give every patient in Hamburg.
7 Caries Prevention Tips That Actually Work
Choose the right toothpaste. with the right fluoride concentration
Not all toothpastes protect equally. According to the DGZMK S3 guideline (2025):
Toddlers with first milk teeth: 1000 ppm fluoride, rice grain-sized amount (up to 24 months), then pea-sized. Adults and teenagers: toothpaste with 1000,1500 ppm fluoride twice daily. For high risk of root caries (elderly patients, dry mouth): 5000 ppm, only on professional recommendation.
Many "natural" fluoride-free toothpastes are marketing, not protection. Fluoride strengthens enamel and disrupts the metabolism of cariogenic bacteria. that is not an opinion, it is decades of evidence.
It is not how much sugar you eat. it is how often
The WHO recommends limiting free sugars to less than 10% of total energy intake. But for caries, frequency matters just as much: every time you eat or drink something sweet, the pH in your mouth drops below the critical threshold of 5.5 and demineralisation of the enamel begins.
A study in Caries Research (Karger, 2019) showed that reducing the amount of sugar without reducing the frequency of consumption is not an effective caries prevention strategy. One piece of cake after lunch is less harmful than four small biscuits throughout the day. Give your saliva at least two hours between meals to neutralise the acid.
Clean between your teeth. every single day
A toothbrush cannot reach 35,40% of tooth surfaces. Approximal caries. cavities between teeth. is one of the most common and least noticeable forms.
A 2019 Cochrane review found that interdental brushes are more effective than dental floss at removing plaque. German dental associations recommend daily interdental cleaning. with floss, brushes or a water flosser, depending on your tooth anatomy. The best tool is the one you will actually use every day.
Seal the chewing surfaces. before it is too late
Fissurenversiegelung (fissure sealants) is one of the most effective caries prevention measures for children. The sealant closes the natural grooves in molars where toothbrushes cannot reach.
What you need to know about GKV coverage: chewing surfaces of teeth 6 and 7 (first and second molars) for children aged 6 to 17. fully covered by GKV. Baby teeth and premolars are private pay. The ideal time is immediately after the permanent tooth fully erupts, before caries has a chance to start.
Use xylitol. as a supplement, not a substitute
Xylitol is a natural sugar substitute that cariogenic bacteria (Streptococcus mutans) cannot ferment. A 2024 systematic review showed: xylitol chewing gum used regularly (3 times daily, at least 5,6 g total) measurably reduces S. mutans counts and the risk of new carious lesions. especially in people already at high risk.
Xylitol is a supplement to good oral hygiene, not a replacement for it. Sugar-free gum after meals when brushing is not possible is a smart habit.
Do not skip professional cleaning (PZR)
Professional dental cleaning in Germany (PZR. Professionelle Zahnreinigung) is not a standard GKV benefit and typically costs 80,120 €. Many insurers subsidise it partially. check with yours.
Long-term Swedish studies show that with regular PZR as part of a prevention programme, caries and periodontitis are almost entirely preventable. PZR includes fluoride application and hygiene coaching, both evidence-based. Recommended frequency: 1,2 times per year.
Keep your Bonusheft and never miss a check-up
The Bonusheft is a uniquely German instrument that many international patients overlook. It is a document where annual preventive visits are recorded. and it directly affects how much GKV pays towards dental prosthetics:
5 consecutive years of documented visits → GKV covers 70% of fixed subsidies for dental prosthetics (instead of 60%). 10 consecutive years → coverage rises to 75%. From 2025 the Bonusheft is being migrated to a digital format within the ePA (electronic patient file).
Early diagnosis of caries at the white-spot stage (before a cavity forms) means treatment without a drill. If dental anxiety is keeping you from going. there are well-proven ways to manage it.
What GKV covers for caries prevention
| Service | GKV coverage |
|---|---|
| Annual preventive check-up | Yes, fully covered |
| Fissure sealants (ages 6,17, molars 6 & 7) | Yes, fully covered |
| Professional cleaning PZR | No (many insurers: partial subsidy) |
| Fluoride varnish for high-risk children | Yes |
| Bonusheft documentation | Yes |
Caries prevention is not one annual dentist visit. It is a daily system: the right toothpaste, less frequent sugar contact, daily interdental cleaning, regular PZR and a conscientiously maintained Bonusheft. Germany has the infrastructure for all of it, you just need to use it.
3 products that damage teeth the most
In 16 years I have seen thousands of patients, and always the same culprits for new cavities. Not sweets, the way you would think.
1. Soft drinks (Cola, Sprite, energy drinks)
The pH of classic Coca-Cola is 2.5. The pH of Red Bull is 3.3. Enamel begins to dissolve below pH 5.5. Every sip of soda means 20-40 minutes of acid attack on the enamel. If you do drink Cola, use a straw and finish it in one go, do not «sip» it for 2 hours.
2. Dried fruit (raisins, dates, dried apricots)
Patients consider this «healthy food». In reality, dried fruit contains 60-80 percent sugar and sticks to teeth for hours. A handful of raisins is worse than a chocolate bar, because the chocolate washes away fast, but raisins stay in the fissures.
3. Juices (even freshly squeezed)
«It is natural, full of vitamins». Yes, but the pH of orange juice is 3.5, and a glass of juice has as much sugar as 6 teaspoons. If you give a child juice instead of water all day, the effect is the same as giving them candy every 30 minutes.
How I assess a patient's caries risk
Not all patients are alike. I split them into 3 risk levels, and the prevention protocol depends on the level.
Low risk
0-1 filling in the last 5 years, good hygiene, low-sugar diet, normal saliva. These patients: check-up once a year, PZR once a year, 1450 ppm fluoride paste, no extra measures.
Medium risk
2-3 fillings in 5 years, or an open cavity right now. PZR every 6 months, fluoride varnish twice a year, interdental brushes every evening, possibly 5000 ppm paste for 3 months.
High risk
4 or more new fillings in 5 years, xerostomia (dry mouth), diabetes, chemotherapy, fixed orthodontic braces. PZR every 3 months, fluoride varnish 4 times a year, 5000 ppm paste daily, CHX gel topically, dietary counselling. Without that, new cavities appear every 4-6 months.