Dental pain relief has been more difficult to achieve than other surgical anesthesias, and it’s only in the last generation that we’ve been able to reliably provide pain relief for our patients. And it’s something people expect as part of a dental visit, so that everything from a dental crown to a minor filling is typically accompanied by local anesthesia.
But it’s only now that we’re really beginning to understand how dental anesthesia works, because it seems to have a unique pain relief mechanism.
Scanning the Brain for Pain
To determine how dental pain relief worked, researchers at the University of Zurich took a detailed look at the brain function of patients who were given dental anesthesia. They recruited 28 men with an average age of 27 (important, because men and women have different pain mechanisms), and hooked them up to a dental pain machine. Okay, so that’s a slight exaggeration, it was similar to an electric pulp tester, a tool used to test whether a darkened tooth is really dead. The electric current was set up to produce what patients reported as a “5” on the Visual Analogue Scale (VAS). The men were then put in a functional magnetic resonance imaging (fMRI) machine while experiencing the pain. fMRI tracks brain activity, showing which regions are active.
After five minutes, the subjects were given an injection, either of anesthesia or of placebo. The subjects who were given anesthesia experienced pain relief about four-and-a-half minutes later, while those that got placebo didn’t experience any relief so they had pain for the entire 16 minutes of the experiment.
In the group that didn’t get anesthesia, activation of a typical pain region was seen. The posterior insula activated initially in both groups, but in the group that actually got anesthesia, activity in this region diminished, and there were more complex interactions between this region and the midbrain, which researchers said indicated that dental pain relief was linked to a special mechanism for its relief.
Beyond Local Anesthesia
This study gives interesting insight into the mechanism by which local anesthesia works. Local anesthesia is common in dental offices, and for many dentists it’s the only kind of anesthesia they can offer.
Although local anesthesia is appropriate and sufficient for many dental procedures, sometimes you will benefit from general anesthesia, as in the case of dental implants and other more invasive procedures. Few dentists can offer this type of anesthesia, and the office of Dr. James B. Polley is proud to be one of them.