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 emulsions.
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.