It’s easy to identify a sonic toothbrush by way of the high rate of speed at which its brush head vibrates. The brush head of a sonic toothbrush is capable of creating in excess of 30,000 brush strokes per minute. (The latest models of sonic toothbrushes can create more than 40,000 brush strokes per minute. In comparison conventional electric toothbrushes typically operate at frequencies ranging between 2,500 and 7,500 strokes per minute). It is the vibrational motion of these brushes that sets them apart from all previous generations of electric toothbrush design.
How does a Sonic toothbrush work?
The cleaning action generated by a sonic toothbrush is actually based on two separate mechanisms. One of these is conventional and is similar in nature to that mechanism employed by all other types of toothbrushes. The second cleaning action is based on a new technology that was first introduced by Sonicare ® and one that is entirely unique to sonic toothbrushes.
1) The primary mode of cleaning that a sonic toothbrush can provide is that which is produced by the scrubbing action of its brush head’s bristles on the surface of the user’s teeth. Of course this method of cleaning teeth is not new. All toothbrushes, both electric and manual, rely on this same principle for removing dental plaque.
2) Sonic toothbrushes are also capable of producing a secondary cleaning action, one based upon a new technology developed by the brush’s creators. This cleaning action is founded on the intense speed at which the bristles of the sonic toothbrush vibrate. This vibratory motion is able to impart energy to the fluids that surround teeth (such as saliva). The motion of these agitated fluids is capable of dislodging dental plaque, even beyond where the bristles of the toothbrush actually touch. Only a sonic toothbrush can make this claim.
Fluid dynamics created by a Sonic toothbrush.
As we’ve just mentioned the unique property of a sonic toothbrush, and that aspect which sets sonic toothbrushes apart from all other types of electric toothbrush designs, is its ability to dislodge and disrupt dental plaque even beyond where the tips of the toothbrush’s bristles actually touch.
We won’t pretend that the cleaning achieved by the fluid dynamics of a sonic toothbrush, the cleaning action that occurs beyond where the tips of the toothbrush’s bristles actually touch, results in a tooth surface that is spotless and totally devoid of dental plaque. The fluid dynamics cleaning action produced by a sonic toothbrush is considered to be one of secondary importance. It augments and enhances that cleaning activity created by the conventional scrubbing action of the toothbrush’s bristles on the surface of teeth.
We would suggest however that the fluid dynamics created by a sonic toothbrush that can disrupt dental plaque (even if just superficially) and also dilute and wash away the toxins produced by the bacteria that live in dental plaque could overall help to mitigate dental plaque’s harmful effects. And while these benefits (which are not provided by other electric toothbrush designs) might only exist for just a short period of time, when one considers the long-term use of a sonic toothbrush over years and decades, these small benefits might prove to be significant. However at this time there is no research that definitively proves this.
Research evaluating the fluid dynamics cleaning action of sonic toothbrushes.
Just to make sure you are well informed about the capabilities of the fluid dynamics cleaning ability of a sonic toothbrush, both its strengths and limitations, here is some information drawn from published dental research. We’d like to point out up front that the setting used for these studies was a “laboratory” environment (in vitro) as opposed to a “clinical” setting (in vivo). To the defense of this criticism, we can see how it would be extremely difficult to quantify the types of measurements described below by direct observation in a person’s mouth.
One study was conducted where tooth enamel samples were allowed to accumulate a film of dental plaque. These samples were then exposed to the brushing action of either a sonic toothbrush or else a conventional, non-sonic type, electric toothbrush. After this brushing period the enamel samples were evaluated for cleanliness by way of viewing them under a scanning electron microscope. Here’s what the study found:
Variation #1: The sonic toothbrush was held in direct contact with the enamel sample. [An evaluation of the conventional cleaning (tooth surface scrubbing) action of sonic toothbrushes.]
95% of the dental plaque harbored on the enamel samples was dislodged if the contact between the sonic toothbrush and the enamel surface was for a duration of at least 5 seconds. If the contact time was 10 seconds or longer essentially all of the dental plaque was removed.
Variation #2: The sonic toothbrush was held 2mm (a little more than 1/16th of an inch) from the surface of the enamel sample surface. [No direct contact between the sonic toothbrush and the enamel sample surface.]
65% of the dental plaque originally inhabiting the enamel sample was removed by the fluid forces generated by the sonic toothbrush when it was held at this distance for at least 5 seconds.
Variation #3: The sonic toothbrush was held 3mm (just short of 1/8th of an inch) from the surface of the enamel sample surface. [No direct contact between the sonic toothbrush and the enamel sample surface.]
The fluid forces that were generated by the sonic toothbrush were able to produce the following cleaning effects in the listed time frames. 58% plaque reduction at 5 seconds, 63% plaque reduction at 10 seconds, 76% plaque reduction at 15 seconds.
Variation #4: The conventional electric toothbrush [one generating 4,200 brush strokes per minute) was held 3mm from the surface of the enamel sample surface. [No direct contact between the electric toothbrush and the enamel sample surface.]
No significant dental plaque removal was observed.
Variation #5: The conventional electric toothbrush (one generating 4,200 brush strokes per minute) was held in direct contact with the enamel sample.
Actually this study did not evaluate this variation. One would have to assume however that when in direct contact with an enamel surface that a modern conventional electric toothbrush would be a very effective plaque remover.
More about the conventional scrubbing action generated by a sonic toothbrush.
As we mentioned previously, the primary mode of cleaning of a sonic toothbrush is conventional. It’s produced by the scrubbing action of the brush’s bristles on the surface of teeth.
Sonic toothbrushes do create a very effective brushing action, primarily due to the high number of brush strokes per minute that these toothbrushes can generate. Sonic toothbrushes are capable of producing more than 30,000 brush strokes per minute. Compare that number to the number of brush strokes created by brushing by hand which is generally considered to be in the neighborhood of 300 strokes per minute. The better non-sonic type electric toothbrushes typically generate somewhere between 2,500 and 7,500 brush strokes per minute, which is only about one fourth the number of brush strokes created by sonic toothbrushes.