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Micro-Abrasion: Comfort Dentistry
The 21st century has come to dentistry. Innovations for dental health, comfort and beauty abound. This includes advancements in lasers, tooth bleaching, porcelain veneers, implants and the types of filling materials used which greatly reduce sensitivity after placement.
In this article I would like to enlighten you on a revolutionary process in restorative and preventive dentistry called micro-abrasion. This process of micro-abrasion is making dental visits better for adults and children, and, if diligently followed, will lessen the dental problems of our children later in life. Specifically, it will reduce the widespread need for root canals and crowns we see in the baby boomers and older. You will understand why most dental problems in adults are of the major variety and stem from teeth that were filled as youngsters.
Here’s why I think this is the most exciting thing I've seen in my 20 years of dentistry:
Early fillings to restore decayed teeth date back to the Phoenicians who pressed gold into teeth over 2000 years ago. Silver amalgam dates back to the Civil War era, and today, is still widely used due to its strength and wearability. The newest materials are tooth-colored resins (composites) and porcelains that are made to adhere to the tooth. The fact that they are "glued" to teeth makes them unique. These fillings, when of reasonable size, restore the tooth to its original strength, whereas silver amalgam tends to cause teeth to fracture over time.
The reason for this is simple. Amalgam contains about 50 percent mercury. Mercury is used in thermometers because it expands and contracts as temperatures change. In the tooth the silver filling expands and contracts about three times as fast as the tooth structure it sits in. Also, amalgam is soft; it creeps and crawls under chewing forces. All this results in cracked teeth. The larger the filling the worse the problem. I would say that over 90 percent of the teeth that need crowns or root canals (major work) have had a silver filling in them. Mercury toxicity is also a worry of some people, but I believe this is insignificant. You get more mercury from your tuna sandwich than from your fillings. Yet, if you have a viable option that eliminates exposure - why not?
The traditional amalgam filling requires that a sufficient amount of tooth structure be removed-healthy or not-to make the filling large enough to be strong. You must also use the dental drill to "undercut" healthy tooth structure in order to lock the filling in place. As dentists, we know that even if the decay is small you can't make the silver filling too shallow or narrow or it will break. All these requirements also weaken teeth.
For the last eight months, I have been removing decay and restoring teeth with "micro-abrasion." Micro-abrasion is a fine stream of air and tiny sand particles that gently removes decay. This will never completely eliminate the drill, but when it is appropriate to use, micro-abrasion is far superior to drilling. The drill removes tooth and decay by spinning a drill bit (better called a bur) at 300,000-400,000 rpm. The flutes of the bur hit the tooth and cause microscopic cracking, heat and vibration. This all points to the need for numbing teeth. Micro-abrasion cleans the cavity like a small sandblaster with no cracking, heat, vibration, or, usually, numbing. Some patients report a cold sensation, but none ever ask to be numbed.
Now you should be able to see how a minimally invaded micro-abraded tooth filled with a composite bonded restoration is the best way to maintain the structural integrity of a tooth for the years ahead. The most ideal use of micro-abrasion is treating decay in children's teeth. When you look at back teeth you notice they are loaded with fissures and pits on the biting surface that tend to gather brown stain. This is where teeth are most susceptible, as the fissures are too narrow to let in one toothbrush bristle, but plenty big for a stadium full of bacteria. These bacteria eat the foods we eat and excrete acids, which cause the fissures to deepen and turn into true decay. Stopping this process is the rationale for sealants. Sealants are liquid resins placed in tooth fissures optimally in the first two years after eruption. This resin is hardened, thus sealing the fissures and preventing bacteria from residing therein. The ages 6 and 12 years are key periods for sealants.
Typically sealants are done by painting the fissure with a mild acid to roughen the surface just enough to hold the sealing resin. Researchers have found that as many as 60 percent of sealants done this way fail in too short a period. This is because the acid doesn't remove debris or bacteria that, inevitably, are hiding deep in the fissure. This is where micro-abrasion shines as it cleans all the crud out of the groove before the sealant is placed. Furthermore, as I am cleaning the debris out of the fissure, I can watch as I follow the stain down the crevice until it's entirely gone. Lo and behold, in many teeth we find the stain goes all the way to the underlying dentin, where it spreads rapidly. At that point the tooth is getting a needed filling instead of just a sealant. I never would have known the tooth was decayed unless I had used micro-abrasion. This scenario shows a common shortcoming of conventional sealants because it is easy to seal over decay that the dentist would not suspect to be under the fissure. Common sense tells us that the sealant won't stick to crud. By the way, the patient rarely knows I've gone from sealant to filling because microabrasion is so painless.
This leads to my next related topic. Fluoride has dropped the decay rate in children's teeth greatly, but by no means has eliminated it. What fluoride has done is change the appearance of decay. The way fluoride works is to be incorporated in the tooth's enamel while it is forming deep in the jaws. Fluoride makes the enamel less soluble, like turning it from chalk to marble. This is why fluoride has reduced decay on the smooth surfaces of the tooth, but it has done nothing for the pits and fissures. By understanding the decay process in fissures as I described above, you can see why the result is that the hole in the top of the tooth is tiny, while the decay may be raging under the enamel. Those of us older than 25 years old may remember the dentist probing teeth and when the explorer "stuck" he'd found decay. Now, dark stains in the groove and, especially, a shadow under the enamel are more diagnostic. The stickiness is gone! Instead, a hard brown plug is present and it's difficult to tell stain from active decay. Fluoride has changed the look of decay! In my opinion, the only way to diagnose incipient decay in fissures is with micro-abrasion.
As you may gather, micro-abrasion is excellent for pit and fissure decay in early stages. It makes a sealant that is second to none. It's also wonderful for removing old tooth-colored fillings. It's not recommended for removing metals such as old amalgams. Amalgam is actually too soft -- the sand particles hit it like mush. Neither could a dentist reduce a tooth for a crown using micro-abrasion. We also still use rotary drills to polish the resins, so the whine of the dental drill is not gone -- just a lot of the anxiety.
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