Microbial / viral contamination with hollow stembrushes of widely sold and marketed electric / sonic toothbrushes.
(clinically PR. Dr. Richarch T, Glass, ph.p)

Since the introduction some decades ago of the synthetic bristles made in Tynex (monofilaments of Nylon by Du Pont) the problem of microbial contamination at the stembrush level was solved.

It must be noted that the before the arrival of Tynex on the market, natural bristles were used on toothbrushes. They presented a medular canal, which was a source of microbial / viral contamination, etc.

Interplak, an electric toothbrush sold in large quantities, was the first device to reinstate, magnified millions of times, this risk of microbial/viral contamination, because its brushing system puts in direct contact the bristling with a hollow cavity inside the stem-brush which is impossible to clean.

Nowadays several other electric toothbrushes are using similar risky brushing system, as for example Sensonic (from Teledyne-Waterpik), Oral-B Plak Control (from Braun) and Interplak’s new model, as well as others, less well known.

An in-depth study of this problem permits the following findings:

The danger comes from the fact that a wide cavity inside the brush stem (where microbial/viral proliferation is favoured) is very close to the bristling.

Several electric toothbrushes are concerned:

• Interplak, as much the new model NT6 as the precedent one, e.g. XPB2 show distances between the bristling and the hollow cavity of respectively 2mm and 2,5mm (*).
• Oral-B, Plak Control from Braun, has a distance of 7mm (*).
• Sensonic from Teledyne-Waterpik, has a distance of 10mm (*).

What is even more dangerous is the fact that the hollow cavities connect the bristling with machines themselves. Consequently the contamination spreads from one user to another, when changing the replaceable stem brushes.

The distances between the bristling and a part of the machine (shaft and /or device), passing by the hollow cavity are:

• for Interplak model NT6-71mm (*) and for model XPB2-49mm (*);
• for Oral-B Plak Control 37mm (*);
• and for Sensonic 66mm (*).

It must be pointed out that even if in some of these electric toothbrushes small holes exist (specifically made for cleaning, or not) it is certainly impossible to insure the cleaning of the stem-brush in these devices.

The brush stem of the Sonicare electric toothbrush (by Optiva) presents less important risks, but it has a protection, which prevents the cleaning of the bristled part of the stem brush. The stem brush also presents an enormous hollow cavity at the bottom part where it joins the machine itself.

Only the Broxo® devices (Broxo® Dent, PerioBrush,Broxo Total®,etc.) do not present this kind of defect with the risks they represent. Their stem brushes do not contain any hollow part. This was also the case of the old model from Waterpik, Touch Tronic.

The different stem brushes compared

See also the clinical related to the presence of bacteria, virus, pathogenes in the edular canal of natural bristles versus Tynex.

Hallow stembrush, the magnetude is immensly superior.

(*) 1mm=0,04 inch