Interview with Dr. Jürg Eppenberger in Zentralschweiz am Sonntag from 14.12.2014

The Swiss usually clean their teeth thoroughly, but very often with the wrong technique. An expert explains how to do it right and why you should switch from manual to sonic toothbrushes - but not just any toothbrush.

For a long time, manual toothbrushes were considered on a par with electric ones. That seems to have changed. Why?

Jürg Eppenberger: Recent studies have shown that sonic toothbrushes with a hydrodynamic effect are generally better for cleaning teeth than manual toothbrushes.

What is a hydrodynamic effect?

Eppenberger: The Zurich dentistry professor Ulrich P. Saxer once aptly described this as the effect of a mountain stream. With over 30,000 movements per minute, the sonic toothbrush creates strong turbulence in the existing mixture of saliva, water and toothpaste. This ensures that the mixture also reaches the bacteria between the teeth at high speed, i.e. where the bristles cannot reach. Sonic toothbrushes therefore not only clean where the bristles are.

Can't it still be done by hand?

Eppenberger: Yes, in principle it is possible to clean with a manual toothbrush in such a way that no damage is caused to teeth and gums. If you are not susceptible to tooth decay, do not injure your gums through careless scrubbing and do not grind down your teeth in the long term by using too much force, you can stick with a manual toothbrush. However, it should be noted that this only applies to around 10 percent of the population (see below: an overview of the different brushes).

When is it essential to switch to a sonic toothbrush?

1. If cleaning with a manual toothbrush is inadequate.
2. In the case of exposed tooth necks (gum recession), which occurs frequently.
3. Gum injuries and wedge-shaped defects (notches on the tooth neck caused by scrubbing with too much force) are also common.
4. For periodontitis (inflammation of the tooth bed).
5. If there is a high risk of caries formation (rare today).
6. Generally for implants, to prevent infection of the surrounding gums.
7. For extensive reconstructions, as these are expensive and the best possible hygiene is indicated.

What should you look out for when buying a sonic toothbrush?

Eppenberger: Among electric toothbrushes, only sonic toothbrushes are recommended - but not all of them, only those that can produce a sufficient hydrodynamic effect. ETH Zurich is in the process of creating a seal of approval for sonic toothbrushes, and the University of Zurich is currently carrying out research into this. However, it is already clear that not all sonic toothbrushes on the market move the bristles with sufficient force to achieve the hydrodynamic cleaning effect. According to the current state of knowledge, the following three brands of brushes meet the criteria according to ETH tests (source: Task Force Sonic Toothbrushes):

1. Sensonic sonic toothbrushes from Waterpik
2. Sonicare sonic toothbrushes from Philips
3. Hydrosonic from Curaprox

Not everyone can afford a sonic toothbrush.

Eppenberger: The purchase costs are indeed higher than for a manual toothbrush, but the cost-benefit ratio is immediately right if it can prevent stains and therefore no treatment is necessary.

How do you brush properly with a sonic toothbrush?

Eppenberger: The handle of the brush head must not touch the teeth. The brush should be switched on with the mouth almost closed without any movement or pressure and the brush head should be positioned at a 45-degree angle to the gums. Small rocking movements forwards and backwards are performed to guide the bristles closer to the interdental spaces. After approximately 5 seconds per tooth, the brush is lifted slightly and moved to the next tooth. In this way, all teeth are systematically cleaned, first inside and then outside. (Note: a leaflet can be found at www.richtigzaehneputzen.ch; a video on correct brushing is available at www.curaprox.ch, via the buttons "Products", "Sonic toothbrush", "Film", "Brushing instructions with Claudia Saxer").

Sonic toothbrushes have different levels. Does the highest one clean best?

Eppenberger: Yes, because a certain minimum deflection and frequency of the bristle oscillation are necessary to trigger the hydrodynamic effect. However, anyone new to cleaning with a sonic toothbrush should start with a lower setting to get used to it.

How long should you brush your teeth?

Eppenberger: Actually 5 seconds per tooth surface, i.e. outside, inside and on the occlusal surface. That would be 7 minutes for 28 teeth (3 x 5 x 28 = 420 seconds). However, it would hardly be accepted to propagate 7 minutes in general, 4 minutes - twice a day - is a good compromise. To achieve optimum results, the brush head should also be replaced every three months.

Does it help to clean for a very long time, i.e. more than 7 minutes?

Eppenberger: Cleaning in the same place for longer is unnecessary and would be harmful, as tooth substance is ground away if you brush too hard and too long in the same place. However, there are people whose gums and bone have receded. With such problem teeth, a cleaning session, including the use of interdental brushes, can take 15 minutes or more without brushing too long in the same place.

Is there no increased risk of injury with sonic toothbrushes?

Eppenberger: No, it is even lower than with manual toothbrushes, even if they are not used correctly. With sonic toothbrushes, good cleaning is possible without a demanding brushing technique, without a great risk of injury and potential damage, even with less concentration and attention.

What about the toothpaste?

Eppenberger: In addition to personal taste preferences, two points are scientifically important in the selection process: firstly, it must contain fluorine (slightly less for children than for adults due to swallowing). Secondly, it must have a suitable, low abrasive effect. Experts refer to the RDA value (relative dentine abrasion), which unfortunately is not usually declared on the paste and sometimes changes. Dentists and dental hygienists will be happy to advise you. Important to know: The higher the RDA value, the more abrasion occurs. So-called "smoker's toothpastes" with a high RDA value should never be used regularly for brushing teeth.

Is brushing your teeth alone enough, or do you need to use other aids?

Eppenberger: For patients who have not had any dental problems for years without cleaning between their teeth, there is no reason to introduce additional interdental cleaning. At least not if they have an annual check-up.

And if you need to clean the spaces between your teeth: Interdental brush or dental floss?

Eppenberger: The gentlest way is to use interdental brushes. Caution is advised when using dental floss, as it can cause cuts to the gums or teeth. The possible consequential damage is then greater than the benefit. Instruction from a dental hygienist or dentist is necessary, as we now know.

Can rinsing solutions replace tooth cleaning with a brush?

Eppenberger: Rinsing solutions are always just additives that cannot replace mechanical cleaning. Rinsing with a fluoride solution instead of brushing your teeth because you are tired is never equivalent. The same applies to tooth-friendly chewing gum. Of course there may be an exception once or twice a year, nothing happens, but unfortunately we are seeing that here and there the exception becomes the rule.

How should children brush their teeth?

Eppenberger: Thanks to the efforts of the SSO dentists, Swiss schoolchildren and their parents know very well how to brush their teeth. Unfortunately, the situation is different for children with a migration background. As a result, the teeth of these children are often far less healthy. Even with good and even more so with poor cleaning: studies show that even children from the age of 4 achieve much better cleaning with sonic toothbrushes than with a manual toothbrush. This is especially true in the presence of braces. The ETH has not yet investigated which sonic toothbrushes are best for children.

The different brushes at a glance

Manual toothbrushes

The hardness and ends of the bristles as well as their degree of packing are decisive. Ideally, the bristles, which are usually made of nylon, should be soft and rounded or brush-like. Soft bristles cause less damage to the gums, but the brush needs to be changed more frequently. Densely packed bristles are better because the toothpaste is better retained. Brushes from Meridol and Sensodyne ProSchmelz with brush-like bristles injure the gums less and clean very thoroughly, especially at the gumline.

Electric toothbrushes

There are two types: oscillating toothbrushes with a round brush head and sonic toothbrushes. Be careful with oscillating toothbrushes: incorrect technique and excessive contact pressure can cause various types of damage, as the round brush heads perform (drilling) rotational movements.

Sonic toothbrushes

This is the name given to electric toothbrushes whose elongated head moves at very high frequencies (15,000 back and forth movements per minute). These frequencies are often referred to as ultrasonic toothbrushes, but strictly speaking this is a misnomer.

Interdental brushes

These are pipe cleaner-like brushes with different diameters for cleaning the interdental spaces. Depending on their size, the appropriate thickness of the interdental brush must be selected. The interdental spaces should be cleaned daily if they are damaged by caries or have been patched with fillings and if periodontitis (inflammation of the tooth bed) is present or has been present. The interdental spaces are cleaned most gently with interdental brushes. Dental floss should only be used where it is not possible to use interdental brushes.

Dr. med. dent. Jürg Eppenberger is an SSO dentist with his own practice in Lucerne, as well as an attending dentist at the Hirslanden Clinic St. Anna, Lucerne.

Author: Dr. med. dent. Jürg Eppenberger
Published in: Neue Luzerner Zeitung on December 14, 2014