If there is one piece of equipment most feared by our patients, it is the dreaded drill, aka the handpiece. These devices are looked upon as implements of pain and suffering. Who can forget the torture scene in the movie Marathon Man? However, virtually every dentist would find it difficult to practice without these trusty instruments.
For patient treatment, handpieces can be primarily divided into two categories: highspeed and slowspeed. There are also handpieces dedicated for laboratory use. This category will cover air-powered, highspeed handpieces.
The air-powered, highspeed handpiece remains the preeminent cavity preparation instrument in North America. Even though alternative preparation concepts such as air abrasion (fading) and hard tissue lasers (emerging) have their advocates, it is difficult to imagine that either of these technologies will replace your trusty handpiece in the near future. Since these instruments are typically used for a single purpose (cutting preparations), they all seem to follow have similar designs, so selecting the one model right for you may depend how you value the various features listed below.
Air vs. Electric
As noted, air-powered handpieces still rule the roost in North America (75%-85% as estimated by several manufacturers), electric-powered handpieces have gained a strong foothold in other areas of the world such as Europe. While electric-powered handpieces have their own category, deciding between the two types should be first on your decision tree.
Yes for electric
The primary reason cited by proponents of electric handpieces is increased torque at lower speed, a combination that allows better control of the handpiece. A secondary reason is that the electric motor can usually be set to rotate at virtually any speed within its limits. This means that with one motor, you can operate at low, medium, and high speeds by merely changing the attachment and the setting on the control box, which provides a host of functions. Finally, since the power of the handpiece is provided by the onboard motor, its performance will not suffer if you are far away from the air compressor and/or other operators are using it at the same time.
No for electric
Size and weight are the two most often voiced complaints about electric handpieces. Especially among dentists suffering from repetitive use injuries such as carpal tunnel syndrome, the added heft of electrics can be a deal killer. When you consider the average weight of highspeed air handpieces being only 3.3oz/93.6g, the same average for electrics (motor + highspeed attachments) is a meaty 7.1oz/201.3g. However, the newest entry into the electric category weighs in under 5.0oz/140g. While this is still heavier than air-driven models, the gap is starting to shrink.
Others reasons for resisting the allure of electrics include the fact that at least some air-powered models cut as fast, although the average veneer cutting speed for air versions is 23 seconds compared to 20 seconds for the electrics. When it comes to noise, the average decibel rating for electrics is 70.2 compared to 70.7 for the air versions, which means they are virtually the same.
And, of course, the cost of electrics is still a stumbling block and is typically substantially more expensive than most air-driven models.
But then there is the hot issue of electrics burning patients. This topic is covered in detail in the Handpieces - Electric category.
To bridge the gap between conventional, air-powered and electric handpieces is a subcategory of the former. Dubbed as a hybrid, this type of handpiece is air-powered, but relies on a microprocessor to regulate the pressure going into the handpiece based on the task at hand. At this time, only one model has been introduced to the market (see Midwest ATC), but more may be on the way.
Various Items to Consider When Purchasing a Handpiece for Restorative Tasks
Light With the emergence of couplers housing LEDs, the illumination from handpieces has taken a major step forward. To measure the luminance of all the products, we placed a 330 bur in all handpieces. We then activated the handpiece and placed it as close to the luminance sensor as we could without actually touching the sensor. These luminance figures may be significantly different than those reported by the manufacturer, but they are closer to what you would experience in the mouth. The light output of each product is included in its commentary.
Water Spray The number and position of the water ports contribute to the cooling capability of the handpiece, lubrication of the tooth structure, and cutting effectiveness through keeping the diamond or carbide bur as free from grinding debris as possible. While having water ports around the bur provides the best water spray, those sprays from ports below the bur can also work.
Push-Button Chuck Pushing a button on the back of the head of the handpiece is the easiest way to insert and remove a bur. Unless indicated, all the handpieces we evaluated have this type of chuck.
Durability With routine autoclaving, all handpieces are being tested for their ability to withstand repeated cycles. For the highspeeds, we have listed the number of autoclave cycles that they can sustain before their performance will be affected. This number comes directly from the manufacturers of these devices.
Noise Just the sound of a handpiece is enough to strike fear in many patients. And noisy handpieces are not good for your hearing either. To measure the noise generated by these products, we placed a 330 bur in all handpieces. We then activated the handpiece and placed it as close to the audible sensor as we could without actually touching the sensor. However, the noise you and your patients are subjected to will typically be lower, since the handpiece would never be directly over your or the ear of the patient. Furthermore, regardless of the decibel rating, some handpieces just sound more shrill than others.
Torque Just like horsepower for a car, which comes in handy when you really need it, more torque usually allows us to cut with more precision. All of the highspeeds tested have excellent torque and could not be stalled out when preparing extracted teeth. The torque in watts listed in each evaluation comes directly from the manufacturers of these devices.
Weight Usually, lighter is better. We weighed all the handpieces with the couplers or motors to get a real world value.
Balance This is how the handpiece feels in your hand and was determined in our clinical evaluations.
Size of the Handpiece The length was measured from the coupler/tubing connection, while the diameter was measured at the widest section. Slimmer, shorter handpieces would be more likely to be comfortable for operators with small hands.
Size of the Head Smaller heads can obviously access more areas in mouths of patients with restricted opening. They usually have less power than their full-size brethren, but this may or may not affect their speed in cutting preparations. Even if they are slightly slower, the slight reduction might be worth it for the additional access you can gain. But the length of a handpiece head may not tell the entire story, since burs may extend out of certain handpieces more than others, especially those designated as mini-head models. Therefore, we measured the length of all heads with a 330 bur in place.
Coupler Allows easy and fast connection to air lines. All of the products use this time-saving system, where you merely snap-on and snap-off a handpiece as needed.
Contamination Oil from handpieces has been implicated in contaminating your preparation and interfering with adhesion. To test this possibility, we exposed dentin specimens to five minutes of handpiece spray to simulate a crown preparation. The handpiece was run first to expel visible lubricant, just as you should do before using a freshly lubricated and autoclaved handpiece. No cleaning procedures were performed, since we did not want to introduce another variable. These specimens were then tested for bond strength. Here are the results:
This test suggests that contamination from handpiece lubricant is a real possibility. Even though bond strengths only dropped slightly, these tests are run on flat teeth that could be scrutinized very closely for contamination. Clinically, we strongly suggest routine use of a cavity cleaner to remove any residual lubricant. In addition, do not use a handpiece if it continues to spray lubricant on teeth you are about to restore.
Handpieces that do not require routine lubrication eliminate this source of contamination and save time. However, their long-term durability may suffer.