How Does Numbing Work?

It may seem like magic to have a dental procedure and not even feel it, but how does this numbing process actually work? Let’s take a look at the interesting science behind one of the dentist’s best tools for patient comfort.

The most common dental anesthetic is lidocaine. It’s what we call a local anesthetic, that is, a pain blocker that only works in a particular small area, as opposed to general anesthetic, where you are “put to sleep”. There are several other similar drugs that also end in “-caine” that are sometimes used, depending on the situation (dentists no longer use novocaine). All of these drugs work by preventing the pain sensation from ever making it from your mouth to your brain. But how does the drug block these signals?

The sensation of pain happens when sodium molecules attach to receptors on your nerve cells. When enough of these receptors are activated, a pain signal travels from one nerve cell to another, all the way to your brain. Lidocaine works by preventing sodium from attaching to the nerve’s receptor. Think of it like a spam blocker on your email account: the lidocaine blocks the message from ever getting to your inbox (your brain).

So why isn’t this effect permanent? Your body has natural defenses that will breakdown chemicals that are foreign to it. Lidocaine takes between 1 and 3 hours to wear off because that’s how long it takes for the body to break it down and eliminate it. We know that the numbness can feel really strange at first, so rest assured that it will be gone soon!

We should note that while lidocaine is extremely safe, you should share your entire medical history with us when we ask. Even conditions that don’t seem related to your oral health can change how drugs like lidocaine affect you. Please ask us if you have questions.

The last thing any dentist wants to do is cause discomfort. If you think about it, that’s the entire purpose of our job: preventing discomfort related to oral health. But sometimes the things we need to do to keep your smile healthy can cause temporary pain, so we numb you up beforehand to prevent this.