by Ian Shuman, DDS
It's 9:00 am, and a moody teen sits in your chair complaining of sensitivity when eating sweets. You want to tell her, "Duh? Stop eating sweets!," but her mom is in the room and you want to maintain a thin veneer of professionalism. So you begin searching for a carious lesion while your mind plays your favorite mental chatter tape that goes something like this:
• Gee whiz, that's a suspicious looking fissure — stained down the center and bordered by a rim of chalky white. Is it a cavity?
• The explorer isn't sticking, but I'm not convinced.
• Do I treat or not?
• If I cut into healthy enamel, I'll feel like a real jerk.
• If I don't treat this area and it grows worse, then I'm to blame.
• What's the temperature in Negril?
That aside, these daily doubts are terrific if you are into beating yourself up. So, to help you avoid a lot of unnecessary bruising and disfigurement to your psyche, here are several surefire methods for diagnosing, accessing, removing, and restoring suspect carious lesions that will get you extremely busy, create excitement in your team, and, ultimately, benefit your patients.
Ah, the 70s: Platform shoes, Star Wars, the oil embargo, Pong, leisure suits, eight track tapes, and CB radios. And in 1979, in a little corner of the world, Dr. Takao Fusayama reported his groundbreaking findings in the field of caries research. By demonstrating the differences between infected carious dentin and uninfected, remineralizable dentin, the path to conservative caries treatment began. Since then, rapid and remarkable changes have occurred in the identification and treatment of the carious lesion.
In the past 20-plus years, these changes have included caries-staining dye and etching and bonding to enamel, followed several years later by the total-etch technique and dentin bonding. More recent advances have included caries diagnosis based on laser light and fluorescence values, LED transillumination, digital radiography, and caries-recognition software. These diagnostic leaps have easily supplanted the old stab-and-peck method of "verdict by explorer." To prove the point, do you have any idea how big the tip of a brand new, deadly sharp explorer is fresh out of the box?
If you answered anything smaller than 30 microns, return to "Go," do not collect $200 and keep paying Sallie Mae. If, however, you answered 30 to 40 microns, then you have way too much time on your hands — get a life! A new explorer can fit into some lesions, but with today's fluoride-hardened enamel surfaces it is no longer simple to diagnose what used to be obvious. In addition, because these occlusal lesions often hide within thickened enamel walls, standard radiographic methods are useless.
As I mentioned, there are several excellent methods for identifying these sheltered cavities. The first is a Class II laser (Diagnodent, KaVo, North America) that can detect and measure the subtle differences in fluorescence values between healthy tooth structure and suspicious areas.
The second method uses CariesFinder, the first FDA-approved caries diagnostic software. An adjunct to the TrexTrophy digital radiography system (PracticeWorks), CariesFinder evaluates the enormous amount of data contained in the digital radiograph and analyzes the probability and presence of a carious lesion.
So, you've diagnosed the presence of caries. Now what?
These lesions can be accessed (often without anesthesia) using a carbide dental rotary instrument in a high-speed handpiece. The Fissurotomy bur system (SS White) has a series of carbide shapes that are designed to reduce vibration and heat build-up and significantly decrease the potential for contact with healthy dentin. Specific lengths in the cutting blades allow for exact depth preparation into the enamel only, if desired. In addition, the Fissurotomy bur provides a divergent preparation design allowing for complete visual evaluation of the lesion during preparation.
So you've accessed the caries. Now what?
Despite the giant advances in caries diagnostic methods and access, one obvious piece was missing from the early-intervention-diagnosis-treatment approach: The ability to completely remove carious dentin while leaving the noninfected, remineralizable dentin undisturbed. Enter the SmartPrep™ instrument (SS White, Towbin, N.J.), the final piece to solve the troubling problem.
This revolutionary device has created a radical change in caries removal and maintains the standard of care as outlined by Dr. Fusayama. The SmartPrep, a resin polymer instrument, is only capable of removing the infected dentin. Because of its material composition, it is incapable of removing any substance harder than infected dentin. Since the uninfected dentin remains undisturbed, there is a significant decrease or even elimination of dentinal tubule stimulation. The result is a significant reduction in perceived pain stimuli, increase patient comfort and virtual elimination of postoperative sensitivity.
Following the access preparation and removal of all sharp enamel edges and tags, the infected dentin can then be removed. This is possible with the SmartPrep instrument. This instrument is especially designed to remove only decayed material after you have created access using another instrument.
The shape and blade configuration of the rotary instrument is designed for safe and effective decay removal. This instrument is used with a slow rotation (200 to 1000 rpm) and a light touch. In all classes of caries preparation, the most superficial, softest decay is removed first. The next layer is removed until the entire cavity has been excavated.
The SmartPrep instrument is designed not to cut or remove enamel, healthy dentin, cementum, composite, or amalgam. The instrument dulls quickly when it comes in contact with these harder substances. As a result, it is designed to conserve healthy tooth structure and protect against unnecessary pulp exposure. Very few, if any, dentinal tubules are contacted or disturbed, which means that most carious lesions can be removed without anesthesia. This makes multiple quadrant work during a single patient appointment possible. Preliminary surveys indicate that most patients who have experienced SmartPrep instruments have preferred this comfortable method (without anesthesia) to that of conventional cavity preps with anesthesia.
Following complete decay removal, contact with healthy dentin will cause the edges of the polymer instrument to roll and become dull. This safety feature occurs because the instrument's polymer composition is softer than healthy dentin. Once dulled, the instrument is disposed of after use.
Ultimately, the economics of this instrument allow for multiple quadrant treatment in a single visit, making restorative procedures faster and more efficient, which increases patient satisfaction.
So you've removed the caries. Now what?
With this highly conservative "microdentistry" approach, restorative treatment is greatly simplified. If deep, a resin-reinforced glass ionomer such as Fuji II (GC America) or Geristore (DenMat) can be used as a base. The remaining area can then be treated using current bonding methods, followed by flowable composite and then standard composite resins.
In shallow preparations that extend up to 3 mm in depth, a perfect aesthetic result can easily be achieved using a translucent flowable composite as the primary restorative material. This will create the seamless illusion of a virgin tooth.
Now, hit the beach!