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.

 

Dental MythBuster #14: A Swollen Lip After a Dental Visit Means You’re Allergic to Novocaine

This is one dental myth that every dentist has to deal with at some point. And that is the myth that if a child’s lip swells up after a dental visit where local anesthetic was used, it always means the child must be allergic to something the dentist injected.

And to make matters worse, this myth is then often propagated by the child’s pediatrician.

What would you think if you saw this the day after your 8 year old got a filling on his lower right molar:

swollen lip from biting while numb after filliing

Lower right lip swollen after a filling was done on the lower right.

That looks pretty nasty right? Something clearly happened here. In my own experience, and in talking to other dentists, parents generally do one of four things upon seeing this:

  1. Parent immediately heads to the closest ER or emergency walk-in clinic.
  2. Parent immediately calls the pediatrician for an emergency appointment and is seen that day.
  3. Parent gets on Google, becomes almost immediately convinced of an incredibly dire situation, and then does either #1 or #2.
  4. Parent calls the dentist office.

Wouldn’t it make sense to call the dentist office? After all, it was the dentist who did the procedure, wouldn’t he/she know what is going on?

But unfortunately, options 1, 2, and 3 are often pursued. And in many of those cases, an incorrect diagnosis is frequently made, which leads to unnecessary finger pointing, as well as wasted time, confusion, and missed school for the child.

So, what does it mean when the lip swells up after a dental appointment when local anesthetic was used?

Swollen Lip = Lip Biting While Numb (99.99% of the time)

Here are two cases I’ve seen in my office:

swollen lip after dental work means lip biting

Swollen lips after dental work. Both patients admitted that they inadvertently bit and/or played with their lips while numb.

The above photos look unpleasant, right? In both cases, lower teeth were given local anesthesia, and that numbness extended to the lip. And in both examples, the patients admitted to repeatedly biting their lip.

The repeated biting led to swelling, bleeding, and bruising. Many times, the child has no recollection of doing it, because the child was numb and felt no pain. But the next day – whoa!

It is quite easy to see how this can come from biting. Go ahead and try to bit your lower right lip with your upper front teeth. Easy, right? Do this a couple of times very hard while you’re numb and you’ll end up looking like the one of the photos.

Why This is not an Allergy

Despite seeing this on a regular basis, many dentists (myself included) still have to deal with accusations and/or false diagnoses of allergies from the injection. Here are some key points:

  • Location. The injection site is nearly always located far away from the traumatized area – in some cases nearly two inches. If it were an allergy, why then is the injection site totally normal? See the photo below.
  • Appearance. In general, allergic reactions do not produce a localized ulcerated area away from the injection of the alleged allergen. The appearance of this is simply not consistent with an allergic reaction.
  • Lack of Systemic Symptoms. Even less severe allergic reactions will produce other symptoms such as dry mouth, hives, and other findings. None of these are typically present in lip biting.
dental injection photo next to tooth

Dental injection adjacent to a 12 year molar. How could this produce an “allergic” reaction on the lip only when the injection site is so far away?

Of course, allergic reactions can occur from the injection. However, they are exceedingly rare, and don’t present like this. For more information, see this three part series.

What Should You Do?

So, if you or your child’s lip is swollen after receiving local anesthetic, what should you do? Call your dentist. Generally speaking, pediatricians, PAs, and NPs do not have experience seeing these types of things, and then come up with what we call “creative diagnoses” which are usually incorrect. General dentists and pediatric dentists see lip biting all the time and can guide you on how to handle it.

But to stress this point, it is a myth that a swollen lip (in the absence of other findings) after a dental visit means you are allergic to lidocaine (mistakenly called novocaine).

Until the next dental myth is busted…

Doc, That Short Hurt – Part II

In Part I of this series, I wrote about why some dental injections hurt while others do not. I approached this topic knowing that there were more than five factors affecting the amount of pain felt from the “shot at the dentist.” So here we go with five more reasons:

6. Size Matters?

Dental needle photo showing needles of different sizes

Wouldn’t you be more scared of the bigger one?

Many people – both dentists and patients – incorrectly assume that the larger the needle, the more painful the dental shot is going to be. While that may seem to be true, some well designed research studies contradict this.

What is true – and this is based on years of my own observations – is that when a patient sees a large needle coming at them – they are WAY more likely to complain that it hurt.

So, the last time you received a painful shot at the dentist, did you look at the needle? If yes, the sheer size may have “psyched you” in to thinking it was going to hurt! Perhaps the time it didn’t hurt was when the dentist and/or assistant distracted you so you didn’t see the needle.

7. Good Good Good Vibrations

It is unlikely that the Beach Boys were thinking of their trips to the dentist when they composed this famous song. However, when it comes to dental injections, vibrations are good.

Many dentists, myself included, will rapidly jiggle and wiggle the area we’re about to inject. Why? According to the Gate Control Theory of Pain, the intense stimulation of the wiggling will essentially prevent the pain of the needle. Stated another way, by wiggling the area so much, that wiggling “closes the gate” that the pain signals need to travel through. See the wikipedia article if you want more info.

Dentalvibe works by creating vibrations to prevent injection pain

The DentalVibe

I can promise you that if I give you an injection without doing any wiggling, you will feel it. However, if I apply techniques from Part I of this post and wiggle a lot, you will barely feel it!

Vibrating can make such a profound impact on whether you feel pain or not that there is even a product you can buy! It is called the DentalVibe and it is basically a professional wiggler. I have not used it but have seen it demonstrated at various dental conventions.

So, if you received a dental injection that hurt, it could be in part because your dentist did not wiggle the area (please note that in some circumstances it is not possible to wiggle).

8. Speed Kills

Many patients think that the most painful part of the injection is the initial pinch as the needle penetrates. In reality, there is another part that can also hurt: the forceful pushing of the fluid (the local anesthetic) into a confined area (the cheek or gums).

photo of teaspoon and tablespoon to depict amounts of dental local anesthetic

Imagine over 1/3rd of a teaspoon injected into you over 4 seconds. Ouch! (Image courtesy wiki commons)

So, what do you think happens when you receive an entire dental shot – 1.8 cc – approx 1/3rd of a teaspoon – into your mouth in under 5 seconds? It will hurt! That entry creates tremendous pressure on the tissue at the injection site, and that leads to pain. This study confirms this fact.

One of the key elements of a pain free injection is to go slowly. I try to do it very slowly – at least 30 seconds – sometimes as long as a minute. In nearly all cases, patients say “Doc, that took a long time, but I didn’t feel a thing!”

9. Local Anesthetic Buffering

This is distantly related to Point #5 –  Choice of Local Anesthetic. But it is different enough – and its impact large enough – to warrant its own entry. And this the buffering of the local anesthetic injection. But what the heck is a buffer?

lidocaine with epinephrine has a pH below 4

This comes at a pH of less than 4.

The pH, which is a measure of the acidity of your bloodstream and tissues, is approximately 7.4. In general, the closer the local anesthetic pH is to 7.4, the less it will sting during administration. One of the most common dental anesthetic formulations in the United States – 2% lidocaine with 1:100,000 epinephrine – has a pH of 3.85! Don’t you think that will sting?

Anutra Medical buffered local anesthetic

The Anutra Local Anesthetic Buffering System I use in my office.

One way to get around this is to buffer the local anesthetic. I won’t bore you with the chemistry but ask any high schooler who took AP Chemistry and he/she can explain it in more detail. But in essence, buffering will raise the pH close to your body’s normal pH. Do you think that an injection at a pH equal to that of your body will sting? No. And many research studies support this.

So why don’t all dentists use buffered local anesthetics? Well, it is not that easy. Local anesthetics cannot be manufactured this way because they would break down with 24-48 hours. However, a new product on the market called Anutra Medical allows dentists to do just this. It has not been widely adopted yet because it is new, requires special supplies be kept in stock, and is also slightly more expensive compared to traditional injections.

Having used the product, I can say with 100% certainty that it works. Patients feel less of the shot. It’s that simple.

10. Your attitude

This is the perhaps the most important factor but also the most difficult one to describe.

If you come in feeling nervous and anxious, act somewhat hostile to the dentist and/or assistant, complain that the topical anesthetic tastes bad, don’t want to open your mouth, stare at the needle as it comes towards you, move and jerk around as the needle goes in, then the injection will hurt. I’ve had patients where I’ve employed nearly every point in this post – and it still hurt because they did not let me do my job.

If you come in nervous but allow yourself to be relaxed, keep an open mind about things, and allow us to use our techniques (super topical anesthetic, wiggling, buffering, etc.), then you will feel little to no pain on injection.

Now I realize that not all dentists are the same – and not all dentists actively seek out new products/techniques to reduce injection pain. But most do. And most will be happy to talk to you about how to reduce the pain of the injection.

Might there be a Part 3 of this series? Maybe. If you have ideas, techniques, or products, email me at nick@directionsindentistry.net and maybe I’ll come up with reasons 11 through 15!

Doc, That Shot Hurt – Part I

As a dentist in private practice, I probably administer local anesthetic about ten times a day. Or to state this in terms that patients like to use, I probably give about ten shots each day. Sometimes more, sometimes less.

Very often, my patient will say something like “Wow, I barely felt that! You’re good.” But other times, I’ll hear “Wow, that hurt! My last dentist didn’t hurt me like this!”

The degree to which you will feel the shot while in the dental chair is dependent upon a number of factors. In fact, there are so many factors that they will be spread across two blog posts. Here’s part 1:

1. Location, Location, Location!

roof of the mouth or palate shot photograph

Any injection on the palate will hurt!

Just as the real estate saying goes, location is probably the number one factor in determining how much, if at all, a dental injection will hurt.

It is universally agreed upon by both dentists and patients that the shot on the roof of the mouth (more formally known as a palatal injection) hurts the most. Why? First off, the type of gum tissue present does not allow for topical anesthetic to work effectively. Secondly, the tissue is so tight and firm that the local anesthetic fluid has literally nowhere to go – making it very painful as the fluid is pushed in.

Conversely, other areas, such as on the outside of an upper tooth, we can make almost painless. You would literally not even know the injection occurred. This, however, assumes other factors are taken into account (those factors are outlined here and in the next post).

2. Topical Anesthetic

topical anesthetic used for dental injections photo

Topical Anesthetic

Topical anesthetic, more frequently referred to as “numbing jelly,” will reduce the initial “pinch” of the injection.

How does it do it?

The jelly is actually an anesthetic – just a viscous form similar to what is injected. When applied to the inside of the mouth, it will numb the area in approximately 1 minute. By making the superficial layers numb, the initial sensation of the pinch of the needle is either eliminated or reduced.

Most dentists use standard topical anesthesia these days. Some dentists, myself included, will use a high powered version that is compounded at a local pharmacy. When used properly, this type can almost completely eliminate the sensation of the needle.

If your dentist does not use topical anestheisa, you should request it. It makes a BIG difference.

3. Temperature

thermometer photo showing temperature affects pain from dental shots

Temperature of the local anesthetic affects how much you feel it.

This should be very obvious. Dental anesthetic is typically at room temperature – approximately 68 degrees Fahrenheit – and your body temperature is approximately 98 degrees Fahrenheit. Don’t you think that the 30 degree difference in temperature will make the shot be more painful?

If you answered yes, you are correct. And many research studies have confirmed this. It can make such a difference that there are actually local anesthetic warmers that dentists can buy.

Having used warmers before, I can attest that they appear to make a difference in how much you feel. But again, this assumes all other techniques are being used.

4. Presence of an Infection

Occasionally, a patient will have a significant dental infection that requires treatment. In many of those cases, an injection needs to made directly into the infected site.

pericoronitis photo where the dental shot will hurt

An injection into this infected tooth – with pericoronitis – will hurt.

Infected tissue is already hypersensitive. And the patient is already extremely distressed. And in many cases, there is a buildup of pus which is causing an increase in pressure. So what happens when you inject 1.8 cc of a local anesthetic into the infected area? You feel pain. This is because of the hypersensitivity, the likely buildup of pus underneath, and the stress.

So, injections into infected areas will always hurt, no matter what I or any other dentist try to do.

5. Choice of Local Anesthetic

First off, we dentists no longer use novocaine. In the United States, there are many different type of local anesthetics available. These include lidocaine, articaine, mepivicaine, bupivicaine, and many others. Some come with epinephrine and some come without.

According to some research studies, the choice of local anesthetic can affect how much pain you feel. This is because of differences in pH (the acidity). In humans, the pH at the injection site is typically 7.4. Doesn’t it make sense that the closer the local anesthetic is to 7.4 the less pain you will feel?

Lidocaine local anesthetic used for dentist shots

Some research says lidocaine hurts more than other local anesthetics!

One local anesthetic, prilocaine (brand name Citanest), has a pH of between 6.0 and 7.0. Many other common local anesthetics have pHs of approximately 5.0. So it stands to reason that prilocaine will hurt less because its pH is much closer to our body’s normal pH.

Well, one study confirms this finding, while another study finds no difference in type of anesthetic.

You might be asking then, why don’t all dentists use prilocaine? Prilocaine does not last as long as other local anesthetics. And many dentists (myself included) feel it is not as effective in getting patients properly numb. So many dentists elect not to use it.

Believe it or not, there are 5 more reasons why some shots hurt more than others. Part II can be found here.