The Whole Tooth: Multitasking Nerves

One of the trickiest things about being a dentist is that so many dental problems are not symptomatic.  What that means is that most people can have a small, medium, and even sometimes large cavity and not know it, because it doesn’t hurt and the cavity is under a shell of hard enamel in the tooth.  Periodontal disease, which is a chronic disease that affects the foundation around the teeth, is notorious for not hurting until the really later stages when it is sometimes difficult to treat.  

One would think that the tooth gods made toothaches so terrible so as to really motivate someone to go to the dentist when their teeth hurt!  A new study says that actually, nerves in teeth can sometimes do the opposite, which is to try to shield the tooth from further damage.

It has always been thought that the nerves in teeth are there to transmit pain.  It makes sense, when you get a toothache, you know loud and clear that something is wrong.  I’ve been told countless times by female patients that a bad toothache was worse pain than childbirth. As I have zero experience with the latter, I always say, “I’ll take your word on that one!”  

Recently, a study at the University of Michigan found that the old theory that there are only pain receptors in teeth may be wrong. They found that the nerves in teeth could actually be multitaskers!  According to an article I read by Ava Barros in recent dental literature, a research team found that neurons inside teeth may protect the teeth from both pain and  from sustaining further damage by triggering a jaw-opening reflex.  That means we might all have a natural protective reflex that prevents us from biting too hard on a bad tooth.

They found that there are special sensory neurons called intradental high-threshold mechanoreceptors that send these signals to the brain within 5 to 15 milliseconds. That is fast. So if you have a bad tooth even without knowing it, your body and teeth might be protecting you.  Bite too hard on some corn nuts?  Don’t worry, your intradental high-threshold mechanoreceptors got you! Your jaw will automatically swing open. How cool is that?

The researchers also suspect that there are other places in our body that may have these specialized nerves. Further study could show us that our bodies play a game of balancing – letting us know when something is wrong, while simultaneously protecting us from further damage.  

One could use this study to justify procrastinating going to the dentist longer – I mean, our bodies might just protect our teeth an extra month or two, right?  But arguably, if you have symptoms in your teeth you must really have a problem! That means your body has  been trying to protect you and things are now obviously breaking down.

This discussion could open up further questions: why don’t teeth problems usually hurt and patients don’t even know they have a cavity or gum disease? What other amazing protective measures can our teeth do to protect us from further damage?  I’m out of space so we’ll save those for another time.  But, I’ll give you a spoiler, our teeth DO have other amazing powers to protect us from pain.