Air Abrasion
Your molar and premolar teeth have chewing surfaces with hills and valleys, and thin grooves running through them. These grooves are great hiding places for bacteria, and form the starting point of almost all chewing surface decay.
In the 1960s, dental sealants were developed. Bonded over these grooves, the idea was that they could keep out decay. In theory, this was an excellent idea in that if this groove were covered over, nothing would be able to get in. However while wearing my 6 power loops, I could see that there were often black or dark areas which could not be felt by the explorer, but were definitely there. I did not feel comfortable simply “sealing” over these areas. Yes, you could keep decay out. But if decay had already started in this area and the seal weren't perfect, that decay could grow to be quite large before you could ever feel it.
What I did for many years to keep this from happening was to open these grooves with the smallest, most delicate instrument that was available at the time, which was a fine finishing bur. After removing the groove, we would proceed with the sealing process.
Air Abrasion to Remove Early Decay
In the early 90s, a much better approach was introduced. It's called air abrasion. Air abrasion is a process in which tiny aluminum oxide particles are used in a very strong stream of air to create sort of a particle beam. When used correctly under good magnification, it literally “vaporizes” the black part of the groove. This entire process is done in a matter of seconds with no heat, noise, or vibration. Not only does this make it painless, but it is very gentle to the teeth. It's like an airbrush or mini sandblast for the teeth. It is the most conservative and best restorative service that we can provide for our patients. If there is decay anywhere under the groove, (and there is in over 75% of the teeth), then it can usually be easily removed with a few more passes with the air abrasion. This is followed up with etching as mentioned above with a sealant, a thin coat of a clear bonding resin, and then is followed by a stronger but still flowable plastic material which is placed where the groove used to be, and is set with a light.
The air abrasion handpiece
There you have it—possibly a lifelong preventative restorative service, without all of the drilling, shots or noise—all of those horrible, terrible things which have always been associated with dentistry for low these many years, all gone forever if we can catch the teeth early enough. Now at your preventative care appointment, it becomes simple to look around the edges of, and at the PRR (preventative resin restoration) and tell immediately if there are any defects, leaks or problems because since all of the black had been removed for the PRR, any new area of stain or decay will be very obvious. No more drilling the entire filling out creating more traumas to the tooth and nerve. These are things of the past, at least for my patients.
The reason I got involved with this process was, as I said, to conservatively remove the groove and any sludge in the tooth before sealing it. Despite all of the great, kind and gentle advantages of this technique, by far to me, the most important and astounding is its help in diagnosis of decay. When I started using this technique, as I said earlier, I knew there was decay under many of the grooves I treated because I could see it with my 6x loops. The amazing and actually frightening part is that ¾ of the teeth have decay; with most of these not being the ones or the areas that you would think. After doing over 50,000 of these procedures, I would not want to wager on which area or which teeth have decay under the groove. There is simply no way to tell. Sometimes I think an area looks really black and yucky, and it turns out to be a very superficial stain, and other times I see a tiny little innocuous-looking spot on a tooth and after following it, it goes halfway through the tooth. What is my point in telling you all of this? While we do today have a laser that we use to diagnose some of the questionable areas, the only way to resolve this issue with 100% certainty is to remove the sludge in the groove to determine the full extent of the situation. The most conservative and most gentle way of doing this is with air abrasion. While this technology was first introduced in the 1950s, and reincarnated in the early 90s and the machines are in their 5th or 6th generation, the great majority of dentists do not use them! I have five of them and I consider them essential to the practice of good dentistry.
Our newest incarnation of this device is called parallel water stream air abrasion, in which as the name implies, a small stream of water accompanies the stream of aluminum oxide at a very precise angle and position, which was calculated using complex mathematical equations, such that this parallel beam or stream if you will when it contacts the tooth, is capable of not only removing or abrading hard enamel, but also softer decay which reaches into the dentin, the second layer of the tooth. This now allows us to quickly, painlessly, easily and without anesthesia to remove decay in teeth that previously would have needed to be numbed and drilled on.