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When is a cavity really a cavity?

If your dentist says you have a cavity, should you assume they're telling you the whole truth?

You knew this day would come.

Your longtime dentist just announced that he’ll be retiring in a few months. You have been going to Dr. Smith for the last 20 years—and he just gets you. He understands that you need a few minutes to calm down after sitting in the dental chair so you can focus on deep breathing. When you insert your earbuds following a cursory hello, he knows you’re not being rude but trying to distract yourself with music. He gently taps you on the shoulder when he needs your attention.

Obviously, you’ll need to find a new dentist. After all, you promised your mother that you would always take care of your teeth and mouth. You eventually settle on someone who’s a younger version of Dr. Smith. His credentials seem solid, the office is modern and clean, and the staff is friendly and helpful.

The new doctor informs you that you have five cavities that require immediate treatment. One of the teeth is even at risk of needing a root canal. You can’t remember the last time you had a filling. And you’re experiencing no pain or sensitivity whatsoever. You’re surprised, confused, and wonder what’s going on.

Did Dr. Smith miss these cavities? Maybe he was so focused on his retirement plans that he overlooked your condition.

Could the new dentist be making this up? You trusted Dr. Smith, but you have no relationship with this new doctor. Could he be trying to drum up business?

Maybe the answer is neither of these two scenarios.

The basics of a cavity

A tooth consists of several layers. The top of the tooth that’s visible above the gumline is referred to as the crown portion. Enamel, the hardest substance in the body, comprises the outermost layer of the crown. Underneath the enamel is a layer called dentin that contains some nerve endings. At the center is the main nerve, or pulp, which extends from the crown portion down through the root(s) of the tooth.

A cavity typically begins with erosion of the enamel. There should be no sensitivity at this point. Once it progresses beyond the enamel into the dentin, the cavity tends to grow both horizontally and vertically. You may be asymptomatic (feeling nothing), or you may have sensitivity to cold and/or sweet. If the cavity penetrates the pulp, the tooth may become infected and abscess. You may experience pain (sometimes severe), swelling, throbbing, and sensitivity to both hot and cold, depending on the extent of infection. However, there’s also a chance you may feel no symptoms.

Some cavities languish in the enamel layer for years, whereas others progress more rapidly. Once the cavity enters the dentin layer, there’s a greater possibility it will grow faster. Many dentists will treat the cavity at this point. If the cavity encroaches into the pulp, treatment is always recommended even if the patient is asymptomatic.

To treat or not to treat

Your dentist will make a judgment call as to when treatment is necessary. This decision is based on a number of factors:

  • Genetics: Some people are more genetically prone to cavities. In those cases, early treatment may be warranted.

  • Diet: If your dentist knows that you consume a lot of sugary foods, it may be reasonable to fill even a small cavity confined to the enamel.

  • Hygiene: Meticulous oral hygiene may keep a cavity the same size for long periods of time.

  • Dry mouth: Saliva has cavity-fighting properties that would be lacking in a dry mouth. Many conditions can cause dry mouth, including side effects of certain medications, mouth breathing, a systemic disorder like Sjӧgren’s syndrome, snoring, and dehydration.

  • Size of the cavity: A small cavity that has entered the dentin layer can occasionally remain stable at that size for many years.

What should you do?

Returning to your situation with two very different diagnoses, how should you proceed?

  • First, don’t assume the worst. Dr. Smith may not be burnt out, nor the new dentist money hungry. Calling something a cavity and determining further action is not black and white; rather, there are shades of gray.

  • Don’t be intimidated by scare tactics. If a dentist says, “You better get this taken care of soon before the tooth abscesses and you end up in excruciating pain,” I would find a dentist who’s more diplomatic and compassionate, even if that were an accurate assessment.

  • Seek a second opinion. It may be prudent to tell the second-opinion doctor you have no intention of getting any treatment at her office; you’re strictly interested in the diagnosis. The doctor then has nothing at stake in rendering an honest opinion.

Remember, pain or a lack of it isn’t necessarily an indication of a problem. Your pain may be from another cause, such as teeth grinding, and not a cavity. Conversely, an absence of pain doesn’t mean there isn’t any pathology.

The bottom line, find a dentist you trust and be trustful.



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