Buying rotary dental equipment is an easy task when you are used to buying the same equipment every time. But, for example, if we think about dental turbines, what happens when it comes to comparing these machines and buying the one that best suits our needs? The task becomes more difficult!
But pay attention, because in today's article we will tell you everything you need to take into account to buy an economical dental turbine that is both durable and effective for your treatments in the dental clinic.
How does a dental turbine work?
It is essential to know how a dental turbine works in order to know where the most problems can occur when working with them.
A dental turbine is a rotary instrument that is driven by air compression directly through the dental unit's hose via a coupling. Among all rotary instruments, it has the highest speed (from 100,000 to 500,000), but the lowest torque. The working speed is about half of the free rotation speed.
As a result of the speed, significant frictional heat is produced by all the driving force on the spindle rotor, which is why it comes integrated with an air and water irrigation system to cool it.
Dental turbines are suitable for work that requires greater resistance to treatment, removing hard tooth tissue such as enamel or prosthetic material. Multiplier contra-angle handpieces can also be used, but the turbine will be more effective.
What are the parts of a dental turbine?
The most important part of the turbine is the rotor, which is the component that does all the work. The standard parts that make it up are shown in the following diagram:
- Spindle: at the centre of the turbine, the shaft that rotates.
- Mandrel: is inside the spindle. This is a hollow tube into which the burr is fitted.
- Impeller: located in the middle (front to back) of the spindle (pressed in here). It is the impeller that captures the air that makes the turbine rotate.
- Front bearing.
- Rear bearing: On each side of the impeller there are bearings, which allow the spindle to rotate by reducing friction.
- O-ring seals: ensure a tight fit inside the turbine head, also reducing vibration.
- Washer / wave washers: are only used on handpieces with automatic chuck to provide lateral tension, keeping the turbine pressed against the cap to facilitate chuck actuation.
- Slinger: is fitted to the front bearing to protect the bearing against dust and contamination.
What should you consider when buying a dental turbine?
When choosing a dental turbine, you should take into account the following variables, in order to choose the one that best suits your needs:
- Grip type: The type of grip is important because as time goes by during treatment, it becomes more difficult to hold the hand on the instrument and the dentist's hand may end up slipping. And this is where ergonomics plays a fundamental role:
- It saves the dentist a lot of effort.
- Prevents risks for both the dentist and the patient
- Quality in every treatment.
- Head size: the smaller the head, the better to provide the dentist with a better view of the operating field. The small head turbine or mini head turbine is mostly used for paediatric dentistry and for patients with reduced jaw opening. It never hurts to have at least one in your dental practice.
- Torque or torsional torque: is the ability of a rotating instrument to continue to rotate despite resistance. Therefore, the higher the torque, the greater the ability to continue rotating.
- Noise: Apart from being an unpleasant sound, it is detrimental to the dentist's health, not only their hearing but also for other organs.
- Vibration: according to the National Institute for Safety and Hygiene at Work, vibration sustained over time in the hand and arm can have a negative impact on dental health professionals, causing vascular, neurological and muscular disorders, among others. To a large extent, the negative effects of vibration will depend on the type of pressure when using the turbine, the posture and the exposure time.
- Irrigation holes: There are two major important reasons for irrigating the working field with an air and water spray. Firstly to cool the tooth to avoid overheating the pulp, as well as to release the material being removed for better visibility. And secondly the irrigation cools the internal system of the head itself so that it does not overheat and break down.
- Number of holes: There are 1, 3 and 4 holes, all equally efficient. The most important point is that they do not clog so that the irrigation is always sufficient.
- Lighting: It is important to know whether the turbine comes with a light or not to facilitate the visibility of the working area. Previously halogen lighting was used, but LED technology has been very successful since it was introduced in 2007. The LED light is more powerful, longer-lasting and has a whiter shade, giving a more realistic, shadow-free view of the work area.
- Power: The more power it has, the more effective the work to be done and the more comfortable the dentist will be to carry out the treatment.
- Material: The material of the turbine is also important as it will indicate the resistance of the instrument's useful life. Among materials such as aluminium, chrome or titanium, titanium is the winner as it is light but at the same time hard and resistant, which are highly demanded properties by dentists, as treatments with rotary instruments are exhausting and an efficient but light handpiece is needed.
- Anti-reflux or anti-backflow system: the former prevents aspiration of the patient's saliva contaminated with bacteria, and the anti-backflow system helps to reduce contamination or cross-infection. The Spanish Dentists' Council recommends these systems to avoid this type of problem.
What can cause dental turbines to fail?
Turbines, like any other appliance, do not last forever and you may ask yourself: What can I do to make them last as long as possible? Take care of the parts that wear out most and always keep them in good condition! Here we'll tell you what the most common faults in dental turbines are due to:
➔Irregular lubrication: the mandrel must always be lubricated before sterilisation to keep it clean and to promote its proper functioning. Fragments can clog the mandrel and affect the burr's hold.
Lubrication is an important task to perform as a matter of routine in the clinic, as this will ensure that the instruments will last as long as we want them to. The manufacturers recommend lubricating the turbine (especially the turbine outlet) between patients, as over time the residues and debris solidify and spoil the turbine's operation, shortening its useful life.
➔Bearings: (specifically the bearing cage) generally fail primarily because of:
- Fragments
- Excessive air pressure
- Very high temperatures during the sterilisation process.
- Wear caused by side loading.
- Water in the air storage tank of the compressor.
- Use of bent cutters or an incorrectly fitted cutter.
- Use of poor quality ball bearings of unknown origin.
- Solid residues inside the head due to unsuitable or insufficient maintenance.
Bearings are generally not covered by manufacturers' warranties, as this is a part of the turbine that is subject to wear and tear from the moment it is first used. Therefore, the more it is lubricated and the less force is applied in its use, the longer it will last. It is therefore recommended to buy turbines with ceramic bearings, as they are more resistant and heat up less.
➔Quickly cooling the handpieces with cold water after sterilisation: Quick cooling can cause deformation of some parts of the turbine, as well as contaminate the already sterilised tools.
➔Starting the turbine without the burr: This may damage the spindle or chuck mechanisms.
It is very important to use the right burrs. One of the most common mistakes when it comes to dental turbines is the use of unsuitable burs that are smaller or larger than the standard diameter (1.59 mm). Unfortunately, there are many thinner or softer burs on the market, which come from low-cost manufacturers and are attractive due to their low price. But if the burs are too thin or too soft, they do not hold well in the chuck. At around 300,000 revolutions per minute or more, sooner or later these burs will start to deflect and eventually cause damage to the chuck.
In addition, standard burrs are also sold that do not fit the turbine correctly even though they appear to do so, and this can cause damage to the grip that holds the turbine as the diameter does not match the standard.
Another factor affecting the performance of the burr is poor wear resistance of the nozzle (the recess into which the cutter is inserted). The nosepiece should be made of carbide or hardened steel and should be separate from the chuck (see drawing below). Many manufacturers of rotors for dental handpieces put the chuck and collet together in one piece because this simplifies the design of the spindle and thus reduces the cost of manufacture.
But this technique is not the best option for increasing the wear resistance of the nozzle. The pressure that the burr undergoes in the course of the operation can wear the nozzle, leaving the burr more room to move radially. Due to this radial movement, dentists can no longer achieve the same precision when working with their handpiece. The increase in this movement also affects the service life of the bearing.
That's it for our article today! We hope it has cleared up any doubts you may have and has helped you to choose the turbine that best suits your needs in the clinic. At Dentaltix we have a wide variety of turbines, of different brands and models, which you can't miss out on!
We hope this article has been useful whether you are looking to upgrade your practice's rotary instruments or if you are just starting out in the world of dentistry or are still a student, we hope you will consider these tips when buying your new dental turbine.
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