Dental Galvanism: Galvanic Shock and Your Teeth

This is certainly an “electrifying” topic (pun intended). After all, learning that electric current can run through your own body can be quite a “shock” to almost anyone!

In dental galvinism, a small amount of electricity is generated when two dissimilar metals in dental restorations make contact, most often when teeth with those metals touch. The result is a harmless but very memorable shock!

There’s Gold in Them Thar Hills

Many years ago, dental gold was the most commonly used material in crowns. In fact, a gold crown was considered the “gold standard” in reliability, especially for back teeth.

Gold onlay which can produce galvanic current if it contacts another metal

Gold onlay on a molar tooth. If this contacts an amalgam, be prepared for a small but real shock!

Dental gold is actually an alloy of many metals. But the biggest component is gold. While gold crowns are not used very frequently anymore, there are still hundreds of thousands – if not a couple of million – Americans with gold in their mouths.

An Amalgamation of Metals

Dental amalgam is a filling material that is still used today. True to its name, it is an amalgam or mixture of many metals. Those metals include silver, mercury, tin, copper, and other elements in trace amounts.

dental amalgam filling that can cause galvanism

Mercury/Silver amalgam fillings on two back teeth. If there’s a gold crown on a tooth below these, look out!

Amalgam is mixed and then placed directly into the the tooth where it will then harden up. With time, the surface will tarnish a bit, but the metal is still exposed and can participate in galvanic shock.

“Current” Explanation on Galvanism

We’ve established that in certain people, there can be two different or dissimilar metals in your mouth. Those metals are bathed in saliva with ions which acts as an ideal conductor of electricity. So what causes the shock?

A silver fork can also produce galvanism.

A silver fork can also produce galvanism.

Certain metals can have what are called electrical potentials. This means that there is the possibility for electrical current to flow to or from that metal. Current can flow if that metal is connected to another, different metal if there is a difference in potential. For example, if a gold crown makes contact with an amalgam filling, current can flow between them because there is a difference in electrical potential between the gold in the gold crown and certain metals in the amalgam filling.

Examples where galvanic shock can occur include:

  1. A gold crown contacting an amalgam filling.
  2. The tine of a silver fork or other utensil contacting a gold crown.
  3. A piece of aluminum foil touching a gold crown or amalgam filling.

When this occurs, a noticeable and memorable shock will occur. If you are not expecting it, you will be very surprised!

How to Treat Dental Galvanism

If this does occur to you, there are different ways to approach it. The easiest way is for your dentist to adjust the filling and/or gold crown so that they can’t touch one another when you chew. If one or both metals become tarnished, the galvanic shock will not occur, but there is no good way to produce a tarnish over the restorations. In more extreme cases, the fillings or crowns can be replaced.

Note: there are many websites and even dentists who claim that dental galvanism can lead to many systemic diseases and other conditions. Proceed with caution should you elect to believe these sources.

Dental MythBuster #16 – You Shouldn’t Have an Infected Tooth Pulled

Tooth with an abscess infection needing treatment

This infection needs treatment ASAP.

This myth is quite pervasive on the internet, but I’ve rarely seen it in private practice. The typical scenario is as follows:

A patient, most often in intense pain and with significant swelling, goes to a dentist. The dentist diagnoses the patient as having an infection. He/she then extracts the tooth and often prescribes antibiotics. 1 to 2 days later, the patient is still having some pain and swelling, and then reaches the conclusion that the tooth should not have been pulled. Ultimately, the infection/swelling resolve.

There are many variations to this dental myth, but the net result is the assumption by the patient that the tooth should not have been extracted because it was infected.

What Causes Dental and Oral Infections

There are many different types of dental infections. Some originate in the tooth itself. Others originate in the tissues directly surrounding a tooth. Still others occur on surfaces within the mouth such as the tongue, cheeks, and floor of the mouth. But the vast majority develop first within a tooth and then spread to the surrounding gums and bone.

decayed and extracted tooth photo that caused an infection

This decayed tooth first developed an infection inside but then it spread to the surrounding areas. Immediate extraction was the only way to deal with this infection.

The above tooth shows a large cavity underneath a crown. The cavity is the source of the infection and is filled with bacteria. Stated another way, the infection first developed within the tooth. With time, it spread to the surrounding gums and bone, resulting in pain and swelling. Immediate extraction was the only option.

Why Infected Teeth Need Immediate Treatment in Nearly all Cases

We’ll take this quote from an Oral Surgery textbook:

“The primary principle of management of teeth infections is to perform surgical drainage and to remove the cause of the infection” (From Contemporary Oral and Maxillofacial Surgery by James Hupp, DMD, MD)

Or, to quote another unnamed surgeon:

“Never let the sun set on pus”

So, what do all these quotes mean? It basically means that surgical intervention is required for tooth infections.

“Surgical intervention” can range from extracting the tooth to draining the pus to other techniques.

Cases When a Tooth Should Not be Extracted

Keep in mind that each and every tooth infection is unique and needs to be evaluated on its own. Factors that a dentist or oral surgeon will consider include the location of the infection, size, consistency (is it a hard swelling or softer), patient’s age, patient’s medications, patient’s medical conditions(s), presence of systemic symptoms (fever, malaise, blood analysis), tooth or teeth involved, previous antibiotic use, and many other factors.

There are some clinicians who believe that immediate extraction should not be done in cases of a very unique type of dental infection called pericoronitis. They recommend surgical drainage instead.

pericoronitis of a lower wisdom tooth showing the infection

Pericoronitis of a lower third molar. Note the redness and swelling of the gum tissue overlying the tooth. Some clinicians believe that immediate extraction should not be done.

But there are other clinicians and textbooks which recommend immediate extraction in cases of pericoronitis.

Dental Myth Busted

As stated earlier, every tooth infection is different and the recommended treatment is based on the unique qualities of that infection. As we learned earlier, in cases of acute infection, surgical intervention is required. And in nearly all cases, getting the tooth pulled is appropriate. So it is a myth to say “you shouldn’t have an infected tooth pulled.”

Dentistry and Art: St Apollonia and the Hours of Catherine of Cleves

While many people are familiar with Baroque era paintings and illustrations of dentistry (see here and here), Gothic representations of dentistry are less well known. The Hours of Catherine of Cleves is considered one of the more famous Gothic era illustrations to survive this period. The work was complied in approximately 1440 in Utrecht, The Netherlands, by an anonymous artist and had been commissioned in honor of Catherine, Duchess of Guelders.

This illustration portrays Saint Apollonia, the patron saint of dentistry.

St Apollonia, patron saint of dentistry seen in the Hours of Catherine of Cleves

Saint Apollonia as depicted in the Hours of Catherine of Cleves. Clicking on the image will show a large, high resolution version.

Apollonia was a 2nd century virgin martyr who was apparently tortured to death. During her torture, all of her teeth were pulled out and/or destroyed. This elevated her to sainthood. Because of this, she was (and still is to a degree) invoked against toothaches in hopes she will help with the pain.

She is portrayed in the Hours holding a pincer (basically, a fancy and antiquated term for tooth forceps) with a tooth in it. She has a rich attire and is gazing at the tooth. The tile pattern on which she is standing shows a dog which has no relation to her.

While this is not the only portrayal of Apollonia, it is one of the earliest, and certainly one of the more famous ones.

In the year 2016, should you have tooth pain, you may certainly invoke Apollonia, but a call to your dentist will likely be more predictable.

The Palatal Injection: Dentistry’s Most Painful Shot

Probably the most frequently commented upon topic on this blog involves what the majority of patients dread the most: the shot. As a result, I’ve posted many articles related to dental injections, including articles on novocaine (no, we don’t use it anymore), epinephrine (the racing heart does not mean you are allergic to it), why some people/teeth are hard to get numb (over ten different reasons), etc.

I’ve also done a two part series on what factors cause some dental injections to hurt more than others (located here and here). However, given the number of comments and questions about palatal injections, it was warranted to create an individual post on what can be considered dentistry’s most painful injection.

What is a Palatal Injection?

This may seem somewhat obvious but it is worth explaining. We’ll start with a photo.

palatal injection photo - most painful dental shot

Injection into the palate on the right side. If it looks painful, it’s because it is painful.

In a palatal injection, local anesthetic is injected into the soft tissue covering the hard palate, just adjacent to the tooth/teeth to be worked upon. It is not an injection into the soft palate nor the uvula. And it is only done for top teeth.

These types of injections are performed when you need the gum tissue on the roof of the mouth to be numb and/or when the procedure requires the tooth to be super numb (like an extraction or root canal). In my experience, for most fillings of upper teeth, palatal injections are NOT needed.

Why Palatal Injections Hurt so Darn Much!

There are two major reasons to explain why these hurt so much:

Tightness/Density – the tissue lining the hard palate is very dense and tight. There’s no “give” to it. The needle initially goes in and is accompanied by a pinch. That pinch is actually not the worst part. The worst part is when the local anesthetic fluid is forced in. There’s literally no room for it because the tissue is so dense. That forcible entry of fluid into this tissue is what causes the pain.

Topical anesthetic does not help with palatal injections

Traditional topical anesthetic does little to help with palatal injections.

Want an analogy? Imagine you have a turkey baster injector. Plunge the injector deep into the breast or thigh. Then try to inject. It will take GREAT force to get even a little fluid into this dense muscle. This is like a palatal injection. Next, move the tip of baster until it is just at the border of the thigh and skin. Then try to inject. There is little to no resistance. Fluid goes in with great ease, taking advantage of the looseness at the skin/muscle junction. This is like most other dental injections.

Traditional Topical Anesthetic Doesn’t Work Well – traditional topical anesthetic, a.k.a numbing jelly, doesn’t penetrate the tissue very easily, regardless of how long you wait. As a result, it exerts little to no effect, thus offering little to no pain relief.

How Palatal Injection Pain Can be Reduced

Fortunately, there are ways to reduce the pain associated with palatal injections. Note, however, that these are all done by the dentist himself/herself (except the last one which involves both dentist and patient).

  1. cotton applicator applying pressure can reduce pain of injection on the palate

    Application of pressure can reduce the pain.

    Waiting – in nearly all cases, if you are going to get an injection on the palate, you will also receive an injection on the cheek side. In many cases, if the dentist waits 10 minutes or so after the “cheek side” injection, some of that local anesthetic will work its way over and partially anesthetize the palate. This will make it so that the palatal injection is less painful.

  2. Pressure – placing firm pressure with a cotton applicator for at 30 seconds can slightly numb or obtund the pain sensation. The pressure is applied on the roof of the mouth right where the injection is going to go.
  3. Super Topical Anesthesia – some dentists will use a pharmacy compounded topical anesthetic that is several times more powerful than traditional topical. Using this correctly can also reduced the pain.
  4. Cold – application of a cold cotton applicator with pressure right before the injection can also reduce the sensation.
  5. Sedation – if you are sedated, you are unlikely to even feel the painful injection, let alone remember it. Sedation dentistry is very effective – I do it routinely in my office.

Not all dentists employ the above techniques. But all dentists are aware of the painful nature of this injection and do their best to only do it when necessary.