It is rare but unfortunately you can get nerve damage after a dental injection. The signs and symptoms are pretty obvious but the good news is that it usually does heal on its own. It may take some time but you will get all of your sensation back and you'll be as good as new.
The bad news is that it is close to impossible to prevent it from happening, despite what the injury attorneys out there try to have you believe. We will explain in detail why it is impractical and impossible to do so.
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Signs and symptoms of nerve damage after dental injection
Nerve damage after a dental injection will result in paresthesia, which is a temporary but abnormal sensation to the body part that the affect nerve innervates.
Here are some signs and symptoms according to this study:
Tongue paresthesia
Lip paresthesia
Tongue and lip paresthesia together
Numbness in teeth, gums, jaw, cheeks, and tongue
Burning sensation
Tingling of the skin
Taste loss
Speech impairment
Uncontrollable drooling
Basically it is a partial loss of sensation and function in regards to your mouth. The way you eat, talk, taste, and feel will be affected.
The symptoms that you experience will vary depending on WHICH nerve gets injured.
Inferior alveolar nerve. Loss of sensation with the lower teeth, lip and chin.
Lingual nerve. About 2/3 of the front of the tongue on the affected side. The other half or side of the tongue will be unaffected.
Only the affected side will experience symptoms of nerve damage from the dental injection. The unaffected side will function completely normally. It is a weird sensation how you can only sense things on one side only.
Statistics for nerve injury after a dental injection
It sounds pretty scary but the condition is actually very rare and it definitely does not happen on a daily basis. In fact, most dentist may never even encounter nerve damage in their entire professional career.
Here are the estimated incidences of nerve damage from an injection at the dentist:
High end estimate - 1:26,762
Low end estimate - 1:800,000
According to those statistics, it is very rare because for a single dental practitioner to have a full 40 hours a week schedule, it only requires 2,000-2,500 active patients. Simply based on the math, most dentists would most likely never encounter having their patient end up with nerve damage.
It would be more likely in a large group practice where you have over ten doctors working because there would also be a lot more active patients. The chances for a case of nerve injury would go up because there would be more injections being given on a single day.
How to tell if your nerve got hit during a dental injection
For the vast majority of cases, most patients wouldn't even know that their nerve got injured during the administration of local anesthetic. It is not until afterwards when the numbness is supposed to wear off but doesn't that patients realize that something is wrong.
However, according to this study, 31 out of the 134 cases of paresthesia, patients reported feeling "an electric shock" during the injection. Ultimately, they suffered symptoms of nerve damage after the dental procedure.
Therefore, one way to tell if you may end up with nerve damage is if you felt an electric shock while you were being given the injection. Just to be clear, even if you didn't feel anything it does not mean that you won't end up with paresthesia. It is just that you're more likely to end up with it if you did feel that sensation.
Based upon what we've personally heard from our colleagues nationwide, most patients do feel that shock or tingle during the injection. If they do, we usually pull back the needle and redirect it elsewhere.
How long does it take for the nerve injury to heal?
The recovery time from the nerve injury varies from person to person. Some may spontaneously recover while others may end up with permanent damage. There isn't really any indication as to which one will happen to you.
Here are the statistics on healing time according to this study:
81% of direct nerve injury will heal within 2 weeks.
Spontaneous complete recovery within 8 weeks for 85-94% of cases.
If your injury lasts longer than 8 weeks, the chances for full recovery will diminish.
Is it possible to prevent nerve damage from a dental injection?
In case you were wondering if there was a way to prevent nerve damage from a dental injection, it is theoretically possible but it is highly impractical and very costly. Due to those reasons, there doesn't exist a method to prevent it but theoretically it can be done.
How to theoretically prevent nerve injury from a dental numbing shot
The vast majority of these injuries result from mandibular nerve blocks, which are used to numb the lower teeth. Unfortunately, it is impossible for your dentist to see where the nerve is. We use landmarks in your mouth but the cold hard truth is that we go in blind.
The entire injection is reliant upon your dentist getting the needle somewhat close to where the nerve is and administering the local anesthestic. Roughly 99.99% of the time, your dentist will either get kind of close or no where near where the nerve it. It is actually considered extremely rare for your dentist to even contact the nerve with the needle.
It is theoretically possible to prevent this, which we will explain but first you need to understand the anatomy of where the nerve is located.
Anatomical considerations
Your dentist can't actually see where the nerve is. That is because it is covered by your gums and that is how it is protected. Can you see your own nerve? We bet you can't! Basically what we're trying to say is that your dentist sort of goes in there blind while only roughly knowing where the location the nerve is in.
It is a rare occurrence and almost like winning the lottery if your nerve actually gets hit. The analogy is just to let you know that no one is trying to injure your nerve and that it is very rare for it to even happen.
Theoretical way to avoid injuring the nerve
You can get a 3D scan of your entire skull to locate where the nerve is and then 3D print an injection guide to guide your dentist's numbing shot. Once both of these two things are completed, you can proceed with your treatment which requires numbing.
The concept is based on how sometimes your dentist may use a "surgical implant guide" to guide the placement of where the dental implants go into the jaw. Your dentist basically places the implant through the guide, which supposedly will land it in the perfect spot with perfect angulation.
Here is a photo showing an implant guide:
Basically how it works is that you place the 3D printed guide over the teeth and then literally drill the implant straight through the designated spot.
We can apply this concept to 3D printing where the injection needle should go to avoid the nerve. Unfortunately, we cannot find any pictures of such an injection guide because no one has ever made one. It does not exist... Nonetheless, theoretically we believe it is possible to produce one.
Highly impractical and very costly
The reason for a 3D printed injection guide to not exist because it is highly impractical and very costly. Do you really want to go get a 3D scan of your entire skull which is a lot of additional radiation and additional cost? Then do you also want to pay for a 3D printed injection guide? The answer is probably no...
Then there is also the fact that even the high end estimate of nerve injury from an injection is only 1 in 26,762 which is very rare. That makes it not very worthwhile time wise and also cost wise. It would also severely delay dental treatment.
Although if this were to become the norm, we believe that radiologists would probably do very well with a massive influx of new business coming from dental offices needing 3D scans of your skull. Then the 3D printing industry would also get a massive boost in profits as well.
What is the treatment for this kind of nerve damage?
There have been a lot of proposed treatments but all of them had mixed results. It is important to note that MOST of the studies out that about repairing nerve damage were about surgical trauma and NOT injury from a dental injection.
One of the few studies which did involve injury from an injection, found that the treatment outcomes were poor. Therefore, you should temper your expectations about some miraculous treatment that will get rid of the permanent numbness. If there is any consolation, the vast majority of these injuries do recover.
Nonetheless, here are some proposed treatments which have been used from surgical trauma to the dental nerve:
Diagnostic injections
Nerve decompression
Nerve grafting
Pharmacological therapy:
Carbamazepine
Phenytoin
Gabapentin
Topiramate
Benzodiazepines
Tricyclic antidepressants
Antispasmodics (e.g., baclofen)
Follow up testing
After the incident, there is a recommended protocol for follow up evaluation to see if there has been any improvement or recovery. It is basically sensory and numbness testing to see if sensations have returned.
The protocol for follow up evaluations are as such:
An evaluation every 2 weeks for 2 months.
Then every 6 weeks for the next 6 months.
Then every 6 months for the next 2 years.
Ultimately, yearly indefinitely if complete recovery has not occurred.
Just our opinion but if there has been no changes after about 2 years, its highly unlikely that anything will happen after that. Typically it wouldn't get worse so it would probably just be as is after that point.
Takeaway
Nerve damage after a dental injection is a very rare occurrence but if it does happen, the most common symptom is persistent numbness afterwards. It may affect the sensations of your teeth, jaw, gums, tongue, and cheek. Sometimes you can even get a burning or tingling sensation in all of the affected areas.
Usually it'll only affect the side, which received the numbing shot. The contralateral side will be unaffected. Fortunately, the vast majority of the injuries do have a complete spontaneous recovery within 8 weeks.
If you think your nerve may have been injured during the local anesthetic administration, you should give your dentist a call right away and go in for another check up. There are follow up protocols which are recommended.
