Dental technologies, techniques, and materials allow us to achieve results that were considered unachievable just several years ago. The public's appreciation for dentistry and it's presence in the media is at an all time high. Whereas dentists used to be associated with pain, held in fear, and regarded as "drillers, fillers, and billers," today they are recognized not only as a healers but as artists. We have come a long way!
Dental manufacturers have provided the profession with "smart" technologies making the daily delivery of dentistry much easier and more efficient. Automix materials, advances in adhesives, and computer and imaging technologies have revolutionized the profession. However there has een little change to the piece of dental equipment that patients fear most, the "drill." The handpiece is the most frequently used tool in the dental office as it performs
ntraorally for tooth preparation and oral surgery as well as extraorally for polishing and adjustments. Over the past several years the use of electric hand-pieces in North America has been growing, and various manufacturers offer electric units.
Although marked as a new technology, the use of electric hand-pieces is not new at all, as they have been used worldwide for many years. Dentists in many countries have long practiced in small single room operatories in older buildings where air lines cannot be brought from a central compressor to a dental unit and have been dependent on electrically powered units.
Electric handpiece technology sits somewhere between the conventional air driven high and low speed as it generates up to 200,000 rpm of rotation which is far less than the 400,000 plus rpm of air driven units. However, they are far more efficient as they have more than three times the cutting power (60 Watts vs. less than 20 Watts).
The electric hand piece will not slow down, stall, or stop as the bur is applied to tooth structure or restorative materials. It keeps on cutting with constant torque. Electric hand-pieces also provide a greater concentricity of the rotating bur during tooth preparation causing less "wobble" than air driven units. This creates more precise margins, less heat build up and less bur chatter resulting in a more defined and cleaner cut. They also don't create the high pitched whining sound that make patients cringe and fear. This is a huge psychological bonus.
In my operatories, both high speed and slow speed tasks have been assumed by electric motors. In fact we use two units to eliminate the need for changing hand-piece heads and settings (Fig. 1). However, one hand piece and controls can easily serve as both a high speed and low speed. The electric hand piece has become an indispensable tool for:
Crown Preparation
We begin our initial reduction using a Great White Ultra carbide #856-018 (SS White, NJ, USA) in order to reduce 1 1/2 to 2mm from the occlusal surface of the tooth (Fig. 2).
This makes the subsequent axial reduction easier as there is less surface area to reduce. Depth cuts are then placed (Figs. 3 & 4) and are joined (Fig. 5) creating a consistent axial reduction of 1mm.
The Great White burs are large and cut very efficiently due to their dentated form. Conventional diamond instruments clog during bulk reduction in crown preparation as their diamond particles clog with debris from cut tooth and restorative material. Ninety percent of the crown preparation is accomplished with this one carbide. For the final finish we switch to a KUT 3139 Coarse diamond (Dental Film Club, Montreal, Canada) (Fig. 6) to refine the axial walls and to a KUT 3833 Coarse diamond (Dental Film Club, Montreal, Canada) to shape the occlusal surface (Fig. 7). We then complete the final preparation switching to fine diamonds and polishers.
1. Removing old porcelain to metal crowns:
Much of our daily dental procedures involve removing older crowns that need replacement. Air driven hand-pieces are very inefficient for this task as the porcelain and underlying metal of the crowns is difficult to cut, creates heat, and causes the bur to stall. These procedures are very hard on the air turbines causing them to wear prematurely necessitating expensive replacement. Electric hand-pieces make removal of existing crowns a snap. We first create a groove in the porcelain using a KUT 2135 Coarse diamond (Dental Film Club, Montreal, Canada) (Fig. 8) which is ideal for grooving porcelain and zirconium.
Once the underlying metal is exposed we permeate it with a #557 carbide (SS White, NJ, USA) (Fig. 9) and pry the crown off with a EB134 hand instrument (Brasseler, USA) (Fig. 10). This procedure becomes fast and efficient.
2. Use as a slow speed:
I used to continuously fight and be frustrated by my air driven slow speed. It would stall, making shaping and adjusting acrylic and metal very aggravating.
Electric hand-pieces never stop. Problem resolved (Fig. 11).
Although electric hand-pieces may be considered to be expensive by some dentists, their benefits in time and efficiency are well worth the investment. New technologies and techniques serve to make the practice of dentistry better, faster, and easier.
OH
Dr. Elliot Mechanic practices esthetic dentistry in Montreal, Quebec. He is Oral Health's editorial board member for esthetics.
Oral Health welcomes this original article.
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Dental manufacturers have provided the profession with "smart" technologies making the daily delivery of dentistry much easier and more efficient
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Electric hand-pieces also provide a greater concentricity of the rotating bur during tooth preparation causing less "wobble" than air driven units
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Electric hand-pieces make removal of existing crowns a snap