Aerosol: Electric highspeed vs. Turbine?
Tobias Schwarz is responsible for the product portfolio restorative dentistry at W&H. Since there is more common awareness about the role of aerosols in infection transmission we are receiving many questions. Whats the right highspeed handpiece to be used to reduce the formation of aerosols? And many more …
Do air turbine handpieces produce more aerosol than electric highspeed handpieces?
The amount of water spray, coming from both kind of handpieces, is basically the same. The essential difference is the bur speed, that would have different acceleration effects on the water drops once they hit the bur as well as different air velocity at the area around the bur. Turbine handpieces are running approximately 400.000 rpm. Electric highspeed handpieces are operated at 200.000 rpm, so half the speed as turbines. As a matter of fact, the intensity how particles are distributed is less. This has a beneficial effect on limiting the exposure of water spray generated aerosol into the dental operatory environment. Additional air, leaking at the turbines head – caused by the drive air to run the turbine - increases the distribution radius of floating particles around the air turbine handpieces head. This effect is significantly less with electric highspeed handpieces as well. Nevertheless, W&H Turbine handpieces are known to have noticeable less air leakage at the turbine head then the average product on the market.
What’s the purpose of the water spray at dental highspeed handpieces?
Highspeed preparation procedures require proper cooling at the contact area between the rotating instrument and the tooth. Especially the heat, generated during gross reduction of tooth structure, would cause significant thermal damage to vital teeth.
That’s why dental highspeed handpieces are equipped with an ideally multi-directional water spray system with 3, 4 or 5 ports directed to the burs tip. Positive side effect is, that the cutting ability of rotating instruments is supported as the water spray does cleans out debris at the cutting part of the bur.
How does the water spray affect the formation of potentially harmful aerosol?
The water spray itself, as it comes from the handpiece, is not a risk at all for infections if the water quality is ensured with the dental delivery system. Only, when the water drop got contact with the patient, it could have absorbed potentially germs which then subsequently rebounds from any surface within the oral cavity and spreads as infectious aerosol.
Why can’t I just turn off the air used for the spray to reduce the formation of aerosol?
A water jet alone would not have enough cooling efficiency for highspeed preparations. That’s why compressed air is added to create the spray. Due to the higher moistening capabilities of this small waterdrops, a much better cooling is ensured – in favour to the vitality of the patient’s teeth!