The majority of the reasons why wisdom teeth hurt when they are on fire is because of the growth of wisdom teeth. As people chew finer and finer food nowadays, and our bone is not enough to erupt all the teeth, the last erupting wisdom tooth does not have enough space to erupt. If the wisdom tooth does not erupt in its normal position, local inflammation will form around it, and this inflammation will recur one at a time when the body’s immunity is low, so there will be recurrent episodes of pericoronitis of the wisdom tooth. So it’s not that the wisdom tooth hurts when it’s on fire, but the wisdom tooth itself has formed a lesion because of its poor eruption, so for that disease, the wisdom tooth needs to be removed.