Want to bet you don’t brush your teeth properly? Expert tips for your pearly whites

Even children know how to brush their teeth. Swiss kindergartens and schools regularly show children how proper dental care works. However, recent studies are now raising concerns about how well people are brushing their teeth. These studies come from Germany, where there are also preventative measures in educational institutions.

The fact is that although a great deal is done to promote good oral hygiene as a preventive measure, the rates of periodontitis and gingivitis (two forms of gum disease) is high worldwide. The situation is only different for dentists. According to this study, dental pros achieve almost perfect oral hygiene and have correspondingly low rates of periodontitis and gingivitis.

Dental plaque is the main cause of inflammation of the gums and periodontium. If it’s not sufficiently removed when brushing your teeth, it can have an unhealthy effect on oral health in the long term. This can lead to bad breath and chronic inflammation of the gums with the threat of tooth loss. Bacterial plaque and tartar are also an excellent breeding ground for tooth decay. The gumline is a hotspot for diseases and complications.

Two studies from 2023 reveal issues with tooth brushing

So why aren’t the rates of gum disease dropping when the majority of adults claim to clean their teeth regularly? Behavioural psychologist from Giessen University Renate Deinzer (link in German) published two studies on the topic in 2023. The professor heads the Institute of Medical Psychology at Justus Liebig University Giessen.

In a study, Deinzer asked the test subjects whether they were aware of what their errors were when brushing their teeth. On average, the test subjects considered their teeth to be very clean – and assumed that they had brushed 70 per cent of the test points (located at the gum line). In fact, it was only around 30 per cent.

For their second study, a test subject group had to brush their teeth «as thoroughly as possible so that they’re completely clean», while the other had to apply their «usual» brushing technique. The test subject group cleaned their teeth significantly longer and used dental floss more frequently.

However, there were no differences in the subsequent amount of plaque. Less than 40 per cent of the test points on the gumline were plaque-free – in both groups. The test subjects had particularly neglected the inside of their teeth and the gaps between their teeth.

So does everyone have to relearn how to brush their teeth?

Obviously, «more is more» isn’t enough when brushing your teeth. So I gave Renate Deinzer, head of the study, a call to find out what’s important when brushing your teeth.

Ms. Deinzer, everyone thinks they have good dental hygiene – but your results show the opposite. How come?

Renate Deinzer: We can only speculate as to why. What has become clear in the course of our research is that what test subjects understand by thorough dental hygiene differs significantly from what experts recommend. For the majority of test subjects, «thorough» is apparently synonymous with «brushing for a long time». The cohort in our study who were encouraged to brush particularly thoroughly simply cleaned frequently brushed areas of the mouth even better. This is an indicator that people equate «thorough» with «time». But, they lack an awareness of what’s important when brushing their teeth.

Apparently it’s to do with the area between the gum line and the teeth?

Exactly, but hardly anyone knows how important this area is. In kindergarten, the main focus is on preventing tooth decay. And tooth decay in children mainly occurs on the chewing surfaces. However, this is the furthest point from the gum line. If people have brushed their teeth for the first 15 years of their lives with this in mind, over time they naturally think: «I can brush my teeth». Plus, I can imagine the specialists and dentists think its obvious to everyone that the area between the tooth and gum is so important. Have you ever had disclosing tablets at your dentist practice to see how well you brushed?

No... For me, that’s something from childhood.

You see – that’s similar to what I hear from dentists. They often say it’s too embarrassing for adults.

Do we need to re-learn how to clean our teeth?

Well, it’s a tragedy because I don’t know of any other health routine that’s practiced by so many people. Which is great. But at the same time, the communication isn’t clear enough, preventing people from having genuinely clean teeth. For the people we had in the lab for the studies, I can definitely say: yes, they need to relearn how to brush their teeth if they want to do it effectively. Obviously, brushing teeth is a strongly ingrained motor skill. Just like handwriting, when we don’t think about it, we don’t write as nicely as when we do think about it. It’s the same with brushing your teeth.

Surely you have concrete tips on which technique is best?

No, we don’t know that yet. Scientific conclusions can’t be made on this. What we do know is, the goal of cleaning your teeth should be to remove all plaque and in particular the plaque at your gum line. So you should run the toothbrush over your gum line. The following tips haven’t yet been scientifically tested, but you can try them out to get your teeth completely clean. Brush your teeth in a fixed order, for example: first the upper jaw, then the lower jaw, then the inside, then the outside, then the chewing surfaces. Carefully clean each individual tooth with ten movements on the inside and outside. Make sure that you can also feel the toothbrush at the gum line so that the bottom of the tooth is also cleaned. Start with the backmost tooth and then work your way up to the centre, tooth by tooth. Time isn’t relevant here. What’s more important is that you have cleaned every tooth inside and out. Then there are the chewing surfaces, where simple scrubbing is sufficient. And it’s really important to get the gaps. It’s recommended that you clean all gaps between your teeth with dental floss, silicone dental sticks or interdental brushes once a day before brushing. Its a good idea to get help from your dental practice on this.

So the 2-minute timer in the bathroom is irrelevant?

Precisely. The most important thing is to proceed systematically. It’s best to start with the backmost tooth and work your way through the mouth as described above. As for whether you do it in a circle, vertically or horizontally, there isn’t enough data to show what would be best. After brushing, use your tongue to feel whether your teeth feel nice and smooth right up to the gum line. If they still feel furry, brush them again. You can also get disclosing tablets over the counter and check the result.

**Is pain an indicator that you’re brushing correctly?

No, it doesn’t have to hurt. However, it’s quite possible that the gums will start to bleed if you go right to the edge. Don’t be put off by this. Bleeding is an indicator of gum inflammation. If brushing is successful, the bleeding usually stops after a few days. If it doesn’t stop, this may be an indication of a periodontal pocket. In this case, you might struggle getting your teeth clean yourself and a trip to the dentist is required.

**How do you brush better: with an electric toothbrush or a manual toothbrush?

A meta-analysis shows electric toothbrushes are slightly superior in terms of plaque removal. However, this is misleading because the test subjects were often instructed in advance when using the electric toothbrush, whereas those using the manual toothbrush weren’t given any instructions on brushing. Or the technique suggested by the manual toothbrush instructions was harder to implement. At the University of Giessen, we compared students who brush their teeth with a manual toothbrush at home with those who use an electric brush. There were no differences at all between the manual toothbrush and the electric model. Finally, I have some good news...

**Oh yeah? Let’s hear it!

You don’t have to brush your teeth after every meal. From a periodontal point of view, one complete plaque removal per day is completely sufficient. When you do it – be it morning or evening or at lunchtime – is probably much less important than whether you do it at all. So brush your teeth super thoroughly when you have the time and nerves to do so. Brush the second time a day to thoroughly distribute the fluoride (in toothpastes against tooth decay) over the enamel.