Why It Can Hurt to Open Your Mouth After a Filling

Every now and then, we get a phone call from a patient who we saw a couple of days earlier. It goes something like this:

I had a filling done on my last tooth on the lower left three days ago. The filling and tooth feel fine, but it hurts to open my mouth, especially if I try to open wide.

We then go on to explain to our patient WHY this is the case and how it is normal.

So why is there pain with opening? There are two major factors.

Dental Injections for Lower Molars

In many cases, the pain while opening is from the injection. For lower molars, most dentists will do a nerve block, which involves a very long needle. See the photo below.

Dental shot for a lower tooth can cause pain while opening

A dental injection used to anesthetize a lower right molar. The needle in this photo is 1 and 1/4 inches long.

As can be seen in the above photo, a needle is inserted into the muscle in the back of the mouth. In most cases, for this injection, the needle goes in nearly to the hub, which would mean approximately 1 and 1/4 inches.

Here’s an analogy: feel your biceps and press it hard enough so you can feel the bone underneath. Then, imagine taking a needle, and inserting it through the biceps, approximately 1 inch, until the needle hits bone. Then, imagine doing that a second time. Don’t you think that moving the arm and using that muscle over the next several days would hurt?

The biceps analogy is very effective. Everyone understands that their arm would be sore. So, if you get an injection back there, or in some cases two, using that muscle in opening and closing can frequently elicit pain for several days afterwards.

Your TMJ (Temporomandibular Joint)

The second source of pain while opening after a filling can be from the actual jaw joint, known as the TMJ (temporomandibular joint). This is the area at which your lower jaw bone connects to the base of the skull.

Your jaw joint was made for all of your daily activities – talking, smiling, eating normal foods, etc. The joint was not designed for “abnormal” tasks such as gum chewing, chewing on ice, or holding your mouth open for your dentist or hygienist to work.

photo of TMJ in a skull which can have pain after opening

The temporomandibular (TMJ) joint. Pain in this joint as well as the muscles and ligaments associated with the joint can occur after a dental visit.

Here’s another analogy: imagine standing on the tips of your toes. Now do this for 5 minute intervals several times, with perhaps 30 second breaks in between. Do this for approximately 45 minutes. Don’t you think that the next day, moving that muscle and the joints would be sore? This assumes you are not a ballet dancer.

A cleaning or a filling of moderate duration will be a lot like the above. Lots of straining to keep your mouth open, which can lead to fatigue and soreness in the muscles and joint. This can then result in pain and soreness on opening for several days.

Some Assumptions

We find that one or both of these reasons are responsible for the pain and soreness approximately 99% of the time. There are other circumstances which can include:

  • Infection of either a tooth or an infection at the injection site.
  • Pain after a surgical procedure such as a lower wisdom tooth extraction.
  • Aphthous ulcers (cold sores) in the back of the throat.
  • Upper respiratory infections, etc.
  • And many others.

Of course there can be other explanations. But for the vast majority of the time, the pain is either from the actual injection or in joint after being open for a prolonged period of time.

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.