Dental handpieces are not cheap. The costs of continually replacing and repairing turbines and contra angles can quickly mount up and put a big dent in a practice’s budget. With some basic understanding of how dental handpieces work and how best to look after them, handpieces can maintain efficiency for longer, have a greater lifespan and ultimately reduce your outgoings.
High speed turbines
How do high speed turbines work?
High speed turbines are dental handpieces powered by air. They remain the most widely used type of handpiece in dental practices. In these handpieces, the turbine is the only moving part. The turbine is made up of a set of two bearings, two O rings and a spindle/chuck. Situated in the head of the handpiece, the upper and lower bearings are supported beneath them by O-rings. These provide vibration and noise dampening.
A typical bearing is made up of an outer race and an inner race. The races create a track for the ball bearings to travel around in. A bearing retainer, also known as a cage, keeps the balls from banging into each other and keeps them straight and smooth. This is the key component in any handpiece and is what normally breaks and causes the handpiece to stop working properly. Any trapped debris in the bearings can cause the races and retainer to wear away and the rotation of the bur to get sloppier.
In the centre of the turbine head is a chuck which holds the dental bur. Wrapped around this is the bur tube, an outer sleeve that is supported by the two bearings at either end. Pressed onto the outside of the bur tube is the rotor. The rotor is what makes the bur tube spin when compressed air is applied.
How to maintain your high speed turbine?
Air pressure
Correct air pressure is critical to handpiece longevity for two reasons. The first relates to the precision bearings located inside the handpiece head which have a recommended pressure that should not be exceeded. Applying air pressure past these recommended limits will cause handpiece failure at a quicker rate. Handpiece repair companies will likely want to know your air pressure to see if it is set too high. Most dental units come pre-equipped with an air pressure gauge. These however are not always the most accurate at measuring pressure because they do not account for the loss of air pressure that occurs as air travels from dental unit to handpiece.
Gauges can be purchased that screw directly into the dental unit tubing and connect to the handpiece to provide an accurate, inline reading of air pressure. Most dental chair service engineers should be able to provide this.Most dental units have settings on them to allow the pressure of each individual handpiece line to be controlled. All handpieces manufacturers should be able to provide details of what this optimum pressure should be. If air pressure is too low, the handpiece will not be as efficient at cutting.
Lubricating your handpiece
A simple definition of CAD/CAM dentistry is the use of digital software to design and manufacture dental restorations and prostheses. CAD stands for computer-aided design and CAM stands for computer-aided manufacturing. The technology can be used to create crowns, dentures, inlays, onlays, bridges and veneers among other things. The speed of the CAD/CAM process allows for dental prosthetics to be designed, manufactured and delivered to the patient in quick time, sometimes the same day. The wider system of using computer assisted technologies to produce restorations is known as CEREC (Chairside Economical Restoration of Aesthetic Ceramics).
Do I need to lubricate the chuck mechanism?
The chuck should be oiled to prevent the button from getting rusty and sticky. Failure to do this can cause problems with pushing the button and inserting or removing the bur.
Chucks should be cleaned out around once a week by putting a drop of oil into where the bur goes and then cleaning out any debris using a small brush.
Investing in an automatic lubrication device, can provide the following advantages:
- Less staff time involved
- Can lubricate multiple handpieces at one time
- Consistent lubrication (less room for human error)
- Measured oil and air flow settings
Price and counter space should be factored in when considering a purchase. Prices typically range between £1000 and £2000.
Other beneficial features to look out for are fully automatic operation and a chuck cleaning attachment like that seen on the BA Ultimate CL0 Lubrication Unit.
What type of autoclave should I use?
Autoclaves, also known as steam sterilizers, are self-sealing steel machines that use a combination of heat and time to kill microorganisms and make dental handpieces safe to use again. The three main classifications of autoclaves are S class autoclaves, B class autoclaves and N class autoclaves.
B class autoclaves are the most suitable machine for a dental practice in accordance with European Standard 13060. They remove air from inside the chamber by means of a vacuum pump, creating a negative pressure that forces steam in. They are generally capable of much faster sterilization and drying cycles, enabling dental staff to work much more efficiently. For more information on how different autoclaves work and what to consider when purchasing one, visit our Ultimate Guide to Autoclaves.
Should handpieces be cleaned before autoclaving?
Dental handpieces do not require cleaning with a disinfectant wipe prior to autoclaving as the sterilizer will kill all microorganisms anyway. Handpieces should however be brushed under running water to remove any external debris. BA recommends that the water should not exceed 38°C and be of at least drinking quality. Handpieces should never be cleaned in an ultrasonic bath prior to sterilizing.Electric handpieces
What to pay attention to
Unlike air driven handpieces that have only one moving part, electric handpieces have several. Because they are driven by an electric motor, electric handpieces have almost unlimited torque. This makes it harder for dentists to realise when the handpiece might be malfunctioning. This provides a greater risk of patient injury and therefore extra care is needed to make sure the handpiece is always working properly.
The following are some quick checks that can be carried out for a strong indication that your handpiece is working properly and does not need repair:
- It should feel smooth when inserting the bur with your fingers without too much grinding or grittiness.
- The sound of the handpiece should be quiet and smooth
- The handpiece should not feel too hot when held against your wrist.
How does an electric handpiece work?
Electric motors, also known as micromotors, cannot turn as fast as air turbines. To power a high-speed handpiece, gears are needed to increase the speed of an electric motor, often by a ratio of 1:5. Electric handpieces are also called speed-increasing handpieces, working at cutting speeds over 180,000 revolutions per minute (rpm). With a 1:5 handpiece, if the motor is turning at 40,000rpm the bur will be turning at 200,000 rpm.