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.

Dentists no longer use Novocain when treating patients. No, this doesn’t mean we’ve somehow managed to make dentistry completely painless (we wish!). We mean that Novocain is no longer the anesthetic of choice for dentists. In fact, it hasn’t been for many years.

Novocain is actually a brand name for procain. It was first created in 1905 and started being used in dentistry soon after. Believe it or not, before that, cocaine was the anesthetic of choice for procedures! Novocain was more effective and didn’t have addictive side effects, so it won out as the anesthetic of choice for many decades.

However, there was a serious side effect that caused dentists to start moving away from using Novocain. Many patients can have allergic reactions, sometimes severe, to the chemical that results as Novocain is processed by the body. By the 1980s, barely any dentists were using Novocain anymore. For the past 30 years or so, lidocain has been the local anesthetic that most dentists use. Lidocain was invented in 1943 and is sometimes called cylocain or lignocain. There are few other local anesthetics that dentists may choose based slight variations in their effect, such as being longer lasting.

Lidocain the same way that Novocain does: it’s a nerve blocker. When lidocain enters nerve cells, it prevents them from sending pain messages to each other, therefore the feeling of pain can never reach your brain. Think of it like an email spam blocker. The spam keeps being sent, but it never reaches your inbox so you never see it or experience it.

Local anesthetics like lidocain are usually used in restorative dental procedures, such as crowns or root canals. They are also used in combination with nitrous oxide (laughing gas) or general anesthesia in more complex procedures such as surgical extractions and placing dental implants.

So if Novocain hasn’t been used dentists in a long time, why do patients under 30 still know what it is and ask about it? Our best guess is that patients have heard about it from their parents, grandparents, or TV and movies. If you’re curious about local anesthetic and how we might use it in your treatment, please feel free to ask!