A tooth abscess can potentially cause lip numbness if the infection is big enough to compress on the mental nerve. The mental nerve does affect lip sensation and proof of that is what happens when your dentist numbs it. The result is numbness of the lower lips after they numb it.
Function of the mental nerve:
Provides chin sensation
Provides lower lip sensation
Provides sensation to the gums of the lower front teeth
How does a tooth abscess cause lip numbness
The only way for a dental abscess to cause lip numbness is if it happens to compress on the mental nerve, which controls the lower lip sensation. In order for this to happen the abscess has to either be close to the mental nerve and big enough to compress it.Size matters
Close to the mental nerve
The teeth which are the closest to the mental nerve and have the greatest potential for causing lip numbness are the lower premolars. The reason is because they are anatomically near the foramen of the nerve, which is where the nerve exits the bone.
Here is a panoramic x-ray showing the location of the two mental nerves:
As you can see, there are two mental foramens and each of them are located underneath the lower premolars.
As you can imagine, if one of the lower premolars become abscessed, the infection can grow big enough to compress on the nerve. If the mental nerve gets compressed you may get some lower lip numbness.
A lower premolar with an abscess won't always compress on the mental nerve because sometimes the nerve can be quite a distance away from the tooth. Therefore the abscess needs to grow BIG enough to reach the nerve and then compress upon it.
Most of the time, smaller abscesses are treated right away so they never get the opportunity to grow large enough to cause you lip numbness. Thank goodness for that right?
It is possible for a tooth abscess to cause lip numbness if the abscessed tooth is near the mental nerve. The mental nerve controls the lower lip sensation and the teeth with abscesses that are most likely to compress the mental nerve would be the lower premolars. Therefore if you're having a strange numbing sensation on your lower lip, you may potentially have an abscessed lower premolar. You should go in for your dental check up if you're feeling that.
Author: Written by Dr David Chen, a LIC dentist in NY.