Can sinus infection as a result of bad wisdom tooth removal job lead to brain infection? is there barrier between the sinus and one's brain?

Yes and no: A sinus infection can result from a good wisdom tooth removal as well. The roots of upper teeth often are positioned in or near the maxillary sinus. If the wisdom tooth is infected or if an infection results after the extraction it can infect the sinus... There is a barrier between the brain and the sinus but all sinus infections should be treated. If it is bad, referral to an ENT is indicated.

Unlikely: If your upper wisdom teeth were removed, there is a possibility of communication with the floor of your maxillary sinuses. These will extend up to the lower portion of your eye socket. To get to your brain, it must then extend to your ethmoid sinuses or sphenoid sinuses. As such, extension to your brain is unlikely.

Excellent question: The most common cause of unilateral (one-sided) maxillary sinusitis is a complication of an upper wisdom tooth extraction. If the infection is not appropriately treated medically or surgically, the sinus infection may spread to the ethmoid sinus, the roof of the ethmoid is very near the frontal lobe of the brain. Yes, there is a 1-2 mm. Barrier but it can be eroded. See your ENT doctor.

Depends: Meningitis can occur through blood bourne transmission from any infection. Veins in the central face lack valves preventing backwards flow, so infections here are particularily prone for spreading to the brain. While there is a barrier it is not foolproof. Hope this helps.