Silver-mercury amalgam was the mainstay of restorative dentistry for generations long before the advent of dental bonding and protective occlusal sealants. Amalgam fillings predate water fluoridation, which began in earnest in the 1950?s (and no, fluoridation was not some Communist plot to poison Americans as some had theorized!).
In those days,it was not uncommon for a child to come from the dentist’s office with the news of five or six cavities, each of which would subsequently be treated and restored with silver-mercury amalgam. While it’s not to be meant in a pejorative way, “drill-and-fill” was a common moniker for that process of treating cavities. Quite a few of baby boomers are walking around with veritable mouthfuls of silver-mercury amalgam fillings.
But times have changed. Thanks to preventive dentistry, healthier diets, and the aforementioned fluoride and sealants, numerous teenagers and young adults have never had a single cavity! But there have been recent reports, such as the one cited in this New York Times article, A Closer Look at Teeth May Mean More Fillings, that heretofore pristine mouths are being diagnosed and treated for a condition (the term used loosely) called “microcavities”. “Microcavities” are not a new phenomenon. In fact, they are essentially a very early stage of the tooth decay process that may or may not develop into a full-blown cavity. Today’s “microcavities” are what dentists have for decades referred to as incipient caries, or to put it more simply, “surface cavities”.
What Causes Cavities Anyway?
A cavity begins with a bacteria-induced acid attack of the enamel surface of a tooth (enamel is the hardest substance in the body). If this acid attack persists, pitting and softening of the tooth structure occurs and renders it susceptible to breakdown. Thus a cavity is born. But incipient caries affect only the enamel of the tooth. They are superficial and do not penetrate beyond the outer half of the tooth’s protective enamel. Incipient caries can be treated with fluoride to re-mineralize the tooth structure and reverse the destruction, thus eliminating the need for a filling.
As mentioned before, not all incipient caries will progress to true cavities. Good clinical judgment is required to make the right decision. “To treat or not to treat, that is the question! Sometimes watchful waiting (along with dietary counseling and fluoride application) is the most prudent course of action. New technologies can help with monitoring and aid in treatment decisions and one such development is Diagnodent, a diagnostic laser that can measure the relative depth and progression of a cavity.
Unfortunately, many of the so-called “microcavities” are being rushed into treatment with fillings. What’s important is this: once a filling is placed into a tooth, the greater the likelihood that the filling will need to be replaced someday.
So, remember, all cavities are not the same. If you are diagnosed with an uncharacteristically large number of cavities, ask questions! While it is not uncommon to see your kids go off to college with perfect teeth and come back with their first cavities (blame it on increased sugar and junk food intake accompanied by a slackening in oral home care) I fear that the “discovery” of “microcavities” has led to over-treatment of what is often a reversible condition.