Many people start to develop small, wedge-shaped grooves in their teeth when they approach middle age, but their dentists have told them for a long time that these are not cavities. Oftentimes, dentists tend to blame these “lesions”, as we call them, on brushing too aggressively with a hard toothbrush. Many patients respond to this accusation by saying that they have not used a hard toothbrush in years. So, if that’s the case, one of two things are happening: our patients are lying to us, or something is occurring naturally in the mouth. The frustrating thing for dentists is that when we restore these lesions with metal or resin—even if it’s done perfectly, the fillings tend to “pop out” after only a few months or years. What’s going on?
Twelve years ago, Dr. John Grippo, proposed his theory for a phenomenon called “abfraction,” which explains what’s happening with these teeth. Essentially, when biting forces do not occur in harmony with how the tooth was designed to function, abnormal repetitive stress is created that fractures the enamel of the tooth at it’s weakest point…the neck of the tooth. Since this process is slow and occurs over a long time at a microscopic level, receding gums and/or sensitive teeth are usually the first signs of abfraction. Because this flexing becomes progressively worse as the tooth weakens as the lesions get deeper, fillings do not stay in very well unless the abnormal bite that caused the problem to begin with is corrected, and even then they probably will not stay in as long as we as dentists would hope.
One might be tempted to question the sense in putting fillings in these teeth if they are going to come out anyway. Well, biting forces are not the only thing that cause these grooves to deepen…. Acids created by diet, plaque, acid reflux disease, etc., cause corrosion that hastens the tooth destruction caused by abfraction. Filling these grooves can slow down the destruction to the tooth that is injured by abfraction, and careful adjustment of the bite can greatly reduce the abfraction. So, when we see these grooves, it’s usually important to fill them, but our patients must realize that the fillings may not stay in place as long as we would like.