“Does a tooth extraction affect the brain?”

No

What I can say is that the local anesthetic (numbing medication) has a minimal effect on your brain when utilized correctly. If excessive amounts are used, it can have a profound effect that is displayed in other ways.

No.

If a car mechanic uses his dirty tool to extract an upper molar tooth, he can get an infection that goes into the brain and it can be fatal. If someone has a lower wisdom tooth that is impacted in the jawbone, extracting it can damage the nerve that gives sensation to that side of the mouth and this could cause permanent numbness. Doctors usually use sterilized instruments and take x-rays showing if impacted teeth are very close to the nerve and will sometimes refuse to extract because of the potential to cause nerve damage. So the answer is that those things are possible, but very, very unlikely and it is foolish to think that it is something you should be worried about.

Having a tooth extracted is done for a reason. Most teeth are extracted using local anesthesia. I am not familiar with any negative research about tooth extraction. Your doctor can also
provide you with some information about tooth extraction.

Nope.

The only way an extraction could affect the brain would be if an infection developed, and then you would know about the infection well before any problems happened in the brain. Perhaps your sources are referring to possible nerve damage. The lower teeth are most commonly associated with nerve damage. Here is how it happens and how to avoid it.
A nerve from the brain along with an artery and a vein enter the lower jaw bone way back beyond the last tooth. They pass through the bone in a round canal giving branches to each tooth along the way. If the root of a tooth being extracted is in contact with the canal, then the canal can be damaged during the process along with its contents - the nerve, artery and/or vein. Fortunately there is available an amazing 3D x-ray machine called a CBCT which will identify precisely where the canal and roots are in relation to one another. Conventional 2D x-rays do not do that. For that reason whenever there is a question regarding the location of the roots and canal, I refer the patient to an oral surgeon. All of the surgeons here in Chicago have this machine. It has become the standard of care for the surgical industry.
I hope that answers your question.

Neal Nealis, DDS

Not having certain infected tooth removed can lead to possible infection of the brain. With any dental anesthesia there can be extended loss of feeling in any nerve associated with the anesthesia. This however is rare and usually transient. Certain extractions can have a rare side effect of feeling loss in certain areas in your mouth or on your face. These potential problems should all be covered covered with you by your dental surgeon and or his staff prior to your treatment as it relates to your case.

Whoever told you that is wrong. You will have no problems having the surgery done.