Don’t Shock Me Bro!

As a dentist in private practice, I administer local anesthesia routinely. Or, in layman’s terms, I give numbing shots daily. That’s just two ways of saying the same thing!

Dental local anesthesia infiltration photo where no electric shock will occur

This type of injection is highly unlikely to give you an electric shock sensation

Occasionally, when I am doing certain injections (and note that there are different types of injections that dentists administer – more on that later), the patient will experience an electric shock sensation originating from the injection area. This ends up being quite a shock to the patient (pun intended) with me then subsequently spending significant time explaining why/what happened.

In addition to seeing this happen periodically in my own office, I get tons of comments and inquires on this blog about “the electric shock they got” from the dentist’s needle. Since nearly all of my articles are either about my own experiences – or from inquires I get on this blog – I decided it was time to do a post on this phenomenon.

Infiltrations versus Nerve Blocks

To understand why the electric shock occurs, a little background information is needed.

Femoral nerve block with an ultrasound

A nerve block guided by ultrasound being done by an Anesthesiologist.

In medicine – and I do consider dentistry to fall under the medical umbrella – there are various techniques for numbing a particular anatomical region. An infiltration is when local anesthetic is deposited directly adjacent to the site to be worked upon. In these cases, the local anesthetic works by affecting tiny, microscopic nerve endings that almost resemble a spider web.

In contrast, with a nerve block, the local anesthetic is deposited adjacent to a large branch of a nerve. This ends up numbing everything that the nerve supplies downstream from the area the anesthetic was administered.

To use an analogy: picture a tree. An infiltration is where anesthetic is placed next to a single leaf. A nerve block is when the anesthetic is placed next to a large branch close to where it is coming off the trunk.

Shock and Awe

When it does occur, the electric shock phenomenon is nearly always associated with a nerve block (as opposed to an infiltration). Why does this occur?

The shock sensation is believed to occur when the needle makes contact with part of the nerve trunk (sources: here, here, and here). The needle basically enters the tissue, touches the actual nerve, and the trauma from that immediate contact provokes a signal that your nervous system perceives and interprets as an electric shock feeling.

photo of needle and skull bone where you give a dental nerve block

In a mandibular nerve block, the needle is aimed right where a large nerve trunk (the inferior alveolar nerve) is about to enter the lower jaw (the mandible)

Some key facts:

  • The incidence of this occurring is between 1.3% to 8% of the time for mandibular nerve blocks (the large difference is based on different sample sizes).
  • Studies have shown that an electric shock sensation does not place the patient in a higher risk category for permanent nerve injury.
  • The most commonly involved nerve is the lingual nerve (which will give rise to a shock sensation in the tongue on the affected side.

As you can see, since the origin of the electric shock is contact with a nerve trunk, it is nearly impossible for this to occur with an infiltration.

What to Do if You Feel the Electric Shock?

With dentists administering millions of injections per year, this occurs on a regular basis throughout the world. Keep in mind:

bullseye showing that electric shock is due to hitting the nerve

An electric shock means your dentist hit a bullseye.

  1. Although the feeling was unpleasant and unexpected, the research clearly shows that this does not place you at a higher risk for permanent nerve issues (see bullet point #2 above).
  2. In many times, you get numb extremely quickly.
  3. This happens to all dentists periodically and this phenomenon alone does not mean your dentist is unqualified or negligent.

Since this occurs when the needle makes contact with the nerve trunk, it means your dentist was dead on with his/her aim. So, if you like, you can congratulate him/her on hitting a bulls-eye! Or, just understand that the human anatomy is unpredictable, and sometimes things like this happen.

Note: the sources used for this post are listed above and are also based on my own experiences. Note that I cannot answer emails to me asking for dental advice. The title for this post is based on the “Don’t Tase me Bro” incident and I have no relationship with Mr. Meyer. This post should not be construed as me providing commentary on that incident.

Dental Local Anesthesia and Ehlers Danlos Syndrome

Ehlers Danlos Syndrome is a group of similar inherited disorders that adversely affect the connective tissue. Patients with this disease experience problems in the skin, joints, blood vessels, and other areas. In addition, some disorders within the syndrome also make the individual resistant to local anesthesia.

Unfortunately very few dentists are aware of this phenomenon. And in addition, there are patients out there with undiagnosed Ehlers Danlos, as well as patients with EDS who are not aware of the issues with local anesthesia. What happens? The patient ends up having a very unpleasant time at the dentist with both the dentist and patient trying to figure out what is going on!

About Ehlers Danlos Syndrome

Ehlers Danlos and dental local anestheticIt is not the point of this blog post to talk about the Syndrome in great detail. There are plenty of other sites out there that accomplish this. However, to understand how this affects dentistry and the dreaded “novocaine shot,” you need to know a bit about the disease.

Ehlers Danlos affects connective tissue. Connective tissue is basically the “glue” that holds other tissue and organs together. Specifially, there are defects with the production of collagen, which is the major protein in connective tissue. While there are six major types of EDS, they are all generally characterized by hypermobile joints (joints that can move way beyond what would be considered normal), joint pain, fragile and easily bruised skin, and other findings.

Not all of the genes responsible for Ehlers Danlos are known and there is active research into all parts of this syndrome.

Why Does Local Anesthesia Not Always Work?

First, it needs to be mentioned that not all of the six types of EDS make the patient resistant to dental local anesthetic. Based on research (here and here), it appears that Type III – Hypermobility is the one in which this phenomenon is seen.

dental injections don't always work in Ehlers Danlos

For those with some types of Ehlers Danlos, you will need MANY injections of very specific anesthetics for effective local anesthesia.

Unfortunately, the mechanism behind why the local anesthesia is less effective is not well understood. The current theory focuses on the “looseness” of the connective tissue. Since the connective tissue is defective, it is very easy for the local anesthetic to quickly move away from the site that is being anesthetized. Stated another way, the connective tissue barriers that hold the local anesthesia in place for the duration of the dental procedure are weak and easily broken.

The end result is that the patient is not sufficiently numb for the dental procedure, leading to pain. Patients get confused, discouraged, angry, and ultimately avoid the dentist, which then makes things even worse down the road.

What Should Dental Patients Do?

Ehler Danlos hypermobility which can affect dental local anesthesia

If you can do this with your thumb, you may have Ehlers Danlos.

As a dentist who treats patients in private practice, I am disappointed that this issue is not well known in the dental community. Ask most dentists and unfortunately, most will not be aware of this. In fact, in what is considered the bible of dental local anesthesia (A Handbook of Local Anesthesia by Stanley Malamed), there is no mention of phenomenon (I searched the 6th edition).

Here are some tips:

  1. Find a dentist who has experience with Ehlers Danlos. There is nothing wrong with calling an office and asking if the dentist is familiar with EDS and this local anesthetic phenomenon.
  2. Identify yourself early on as having Ehlers Danlos to the hygienist and dentist.
  3. Find an opportunity to meet with the dentist in advance of any procedure requiring local anesthetic to review the plan (remember that the office may have to order a special type of local anesthetic).
  4. Consider taking a medication beforehand to relax you.
  5. Be ready for a longer than normal appointment.
  6. At the completion of the appointment, especially if it was successful, ask the dentist for detailed records on the local anesthesia (what local anesthetic, how much administered, where administered, etc.)

In some cases, nitrous oxide and/or IV sedation may be necessary to complement the local anesthesia.

My own experience treating patients with Ehlers Danlos has shown that most of the time, we can achieve local anesthesia. I attribute my success to knowing the pharmacology of local anesthetics as well as other injection techniques. To use a pun based on EDS, with a little “flexibility” in selecting local anesthetics and injection sites, we can nearly always succeed!

Aspirin next to your tooth helps your heart and not your toothache

Since publishing Dental MythBuster #5 – Placing aspirin on a tooth cures a toothache, the post has racked up over 47,000 views and averages approximately 100 per day (as of March 2016). No wonder. People are always looking for home remedies and a do-it-yourself solution for a toothache is searched upon quite often.

low_dose_aspirin

Placing this next to your tooth might give you an unexpected reaction

Many have posted comments claiming I am wrong.  But the only piece of evidence offered by the posters is simply a summary of their own personal experience(s). It goes something like this:

I did it – and the pain went away – so it works – so you’re wrong.

Making broad generalizations based upon one single experience does not prove anything. What if I wrote this:

I smoked 2 packs a day for fifty years and I don’t have lung cancer. So cigarettes must not cause lung cancer then.

Would you agree with that person? Or would you say – everyone knows smoking will cause lung cancer – you can’t generalize based on one experience.

A Home Remedy for a Heart Attack

No, this is not a joke. I am bringing up this specific example to show that placing an aspirin next to a broken tooth will do more for your heart than the tooth!

Many readers know that if/when a heart attack is suspected, one of the first things you are supposed to do (besides calling 911) is to chew on an aspirin. Note that we said chew and not swallow. There are literally hundreds of sources for this, including the Red Cross and the American Heart Association. In fact, it is a critical part of the BLS/CPR algorithm (here is a link from the New York Times).

broken tooth showing where you should NOT put an aspirin

Placing aspirin next to this broken tooth will result in burned gums and a healthy heart but no toothache relief.

Why should you chew and not swallow the aspirin?

Simple. Because the thin mucous membrane of the mouth – especially under the tongue – allows for the aspirin to be absorbed into the bloodstream quickly. In this study, chewed aspirin exerted its desired effect almost two and half times faster than aspirin that was swallowed.

So, to summarize, when you place an aspirin in most areas of the mouth, it goes into the bloodstream quickly and goes to exert its effects on the heart and other organs – all far away from the mouth.

But What about the Tooth?

So if the asprin is absorbed and enters the bloodstream, how does it help the tooth? It doesn’t. Or more accurately, for toothache relief, it doesn’t matter whether you swallow, chew, or place the aspirin next to the tooth.

aspirin for a toothache

For a toothache, it doesn’t matter if you chew or swallow.

To those who are still claiming that placement of an aspirin next to the tooth will cure a toothache, I’ll ask this question:

How does the aspirin know to leave the mouth and go to the coronary arteries of a heart attack victim but to stay next to a throbbing tooth?

It doesn’t. This is why placement of an aspirin next a tooth won’t work any more effectively for toothache than swallowing it. The only difference is that you can get a nasty chemical burn of your gums (as seen in the first post).

Dentistry and Art: The Shoe is on the Other Foot by Johan Christian Schoeller

Johan Christian Schoeller was an Austrian painter and engraver who lived from 1782 to 1851. He resided in a number of cities throughout Europe but spent most of his adult life in Vienna. However, dentistry – along with tooth pain – does not discriminate based on country of origin- so he was experienced in observing scenes like this:

The shoe is on the Other Foot engraving by Johan Christian Schoeller

The Shoe is on the Other Foot – an engraving by Johan Christian Schoeller

In the above scene, you can see a patient holding a towel next to his face. The “dentist” has apparently extracted the wrong tooth – much to the dismay of the seated patient. Behind the “dentist” is another individual suffering a toothache – as evidenced by the red bandanna/scarf around his head. In the background, you can see several skulls, books, and other tools used by the “dentist.”

What’s missing from this scene which was created in 1839? X-rays, gloves, local anesthetic, sterile instruments, and about a hundred other technologies that were introduced since then. This work can be found in the National Library of Medicine in Bethesda, Maryland.