Compressed air is indispensable in dental practices. For
instance, it ensures a long-term adhesive bond when dry
blowing in restorative therapy and prosthetics. More importantly
it can reduce pathogen contamination at the place of treatment
and helps avoid infections. But this presupposes that the
compressed air itself is completely hygienic. Simple filters alone
are not enough. The following article explains the important
factors in dental air.
Compressed air is required in many applications in dentistry. It drives
a whole range of appliances and components – from turbines in
hand pieces and pressure molding machines for the pressure
molding technique up to the control of precision milling cutters in the
laboratory. Not least, dental air is used for drying the treatment site
directly in the mouth of the patient. But in all these areas of
application various factors have to be taken into account and are
connected with risks which should not be underestimated.
Water as a risk factor
Compressed air with an excessive water content reduces the
adhesive strength of dental adhesive. There is also a risk of
corrosion of the driven instruments. In addition, moist air – especially
if it is warm too – creates the ideal environment for bacteria, viruses
and fungi: Alarm stage red! The dentist must always expect the
presence of open wounds in the patient’s mouth.
If the finest particles are also added to this, together with water and
oil they can form an emery paste that acts like sand in a gearbox. It
impairs the functioning of all bearings in the turbine, disrupts the air
circulation in turbine heads and destroys the bearings and shaft. The
cooling required for rapidly rotating components is diminished,
causing the wear of many components. Even the patient can become
aware of this in the form of unpleasant musty odors.
Oil as a risk factor
Simple appliances in the industry use tried-and-tested oil lubrication.
It reduces the wear of piston, bearings and shafts and supports the
work with low-pulsation, constant air output. But this also means
potential exposure to residues of oil droplets, oil mist or oil/water
This potential contamination also involves several undesirable risks.
The viscous lubricating oil can add to the low viscosity oil of dental
turbines and, especially after partial oxidation and resin deposits
when exposed to heat, the gaskets in turbine heads can stick. This
leads to total failure of the turbine. Any oil film in the patient’s mouth
will prevent the adhesion of composites. which can result in the
failure of the restorative therapy.
The industrial solution
Air is used as a propellant medium in industrial compressors. It must
achieve certain volume flows and pressures yet does not necessarily
satisfy special hygienic requirements. Mainly the task is only in
transportation, assembly, control, etc. Stricter conditions are imposed
by the foodstuffs or pharmaceuticals industries – and, naturally, the
most restrictive regulations must be observed where air is used as
the working medium for treatment in immediate contact with hard and
soft tissues directly on the patient.
The dental solution
Dental compressors typically have an integrated air drying process.
Modern membrane drying systems work the most efficiently. Firstly
they bring the compressed air to room temperature in a cooler. Next
the air flows through thin membrane fibers that further dehumidifies
it. Dry purging air on the other side of the membrane fibers absorbs
more moisture. This means that three times more water is separated
than in conventional systems. Furthermore, compressors with
conventional drying systems can only utilize around 50 percent of
their capacity as the drying medium must be regenerated at regular
intervals. This is not necessary in the membrane-drying unit – the
compressor can run non-stop 24 hours a day. A membrane-drying
unit provides dependable, high-quality dental air at all times.
In the case of conventional air drying, the compressed air is cooled
first, e.g. via a cooling coil. The moisture that condenses out is “flung
to the edge”, as it were, in a cyclone chamber by specifically targeted
turbulence and pulled downwards into a separation tank by the force
of gravity. Residual moisture is typically eliminated by an adsorption
agent. This is regenerated in the shut-off phase of the compressor.
Currently, there is not a single compressed air system working on the
basis of oil-lubricated pistons that can guarantee 100 % oil-free air.
The dental solution can, therefore, only be an oil-free compressor. In
such “self-lubricating” systems, the pistons move in finely machined
cylinder bores. The piston rings are made from a special compound
that is distinguished by outstanding sliding properties. And where
there is no oil, it cannot affect the function of a dental turbine or the
adhesive strength of an adhesive.
More safety – less maintenance
Oil-free, dry and hygienic – apart from minimized infection risk and
greater treatment efficiency, this also leads to lower maintenance.
The annual filter change that the dental team easily carries out itself
in seconds is normally all that is required. Apart from that,
compressors from leading manufacturers (e.g. Dürr Dental,
Bietigheim-Bissingen, Germany) are completely maintenance-free.
This also saves the practice expensive technician hours and
bothersome down times. The team need not be concerned about
such a compressor after installation.
State of the art
Compressors from Dürr Dental are equipped with membrane
technology as standard. Existing systems can be retrofitted with a
membrane-drying unit if necessary. Models that precisely match the
respective requirements are available for any size of practice – from
“Tornado” for one treatment room, through the “Duo “and “Trio”, right
up to the “Quattro” for four to five therapists. In the case of models
with the “Tandem” name affix, the performance can be simply doubled with
an additional unit for extending the practice.
The “Quattro Tandem” model, that produces its enormous output
from two units with a total of eight cylinders, is particularly suitable for
larger dental practices and dental laboratories. For clinics, Dürr
Dental offers equipment with compressed air stations for 30 to 50
treatment places and beyond that if necessary. Such systems are
running, for instance, at the universities of Prague, Toulouse,
Santiago de Chile, Madrid and Valencia – to name but a few.
Not only do compressed air supply systems simplify the treatment of
the patient, they also play an important role in practice hygiene.
Systems with membrane drying units run extremely reliably for
prolonged periods entirely free of maintenance and offer maximum
security. It saves the practice unnecessary work and costs due to
premature wear and ensures the success of the treatment through
durable fillings. Also with regard to the increased mobility of people,
growing tourism and continually emerging new illnesses, high-quality
and robust compressed air systems for minimizing infections are a
solid investment for every dental practice to ensure therapeutic and
hygienic security for many years to come.