Wisdom tooth extraction

A wisdom tooth that has come in straight, has room, meets an opposing tooth and that you can clean properly should absolutely be kept. It is an ordinary molar and there is no medical reason to take it out.

The problem is the angled tooth, usually tilted forward into the back surface of the second molar. That contact point is a food trap a toothbrush can never reach. And the consequence does not fall on the wisdom tooth — it falls on the second molar, the main chewing tooth you need for life. Decay on the distal surface of a second molar caused by a wisdom tooth is one of the saddest reasons for extraction in dentistry, precisely because it was entirely preventable.

So the working principle is neither "all wisdom teeth come out" nor "wait until it hurts". It is: take an X-ray, look at the angle, and if that tooth is harming or will certainly harm the tooth beside it, remove it early, while you are young and bone heals quickly.

Running through the lower jaw is the nerve canal that supplies sensation to the lower lip, the chin and the lower teeth. The roots of a lower wisdom tooth can sit close to it, touch it, or even wrap around it.

A panoramic X-ray is a two-dimensional image, so when a root appears to overlap the canal, it cannot tell you whether the tooth lies inside or outside it. A Cone Beam CT reconstructs it in three dimensions and answers that question precisely, with the actual distance in millimetres.

The difference in management is substantial. Where there is a safe margin, removal proceeds normally. Where the roots hug the canal, the tooth is sectioned and lifted out in pieces, or in some cases a coronectomy is considered — removing the crown and leaving the root safely in place rather than forcing the whole tooth out. Permanent lip numbness is among the most distressing complications there is, and most of it is prevented at the stage of reading the scan.

Once the tooth is out, a blood clot forms in the socket. That clot covers the bone and the nerve endings underneath, and it is also the scaffold new tissue grows into. It is the body's own dressing.

If the clot is dislodged or breaks down early, the bone of the socket is left exposed to the mouth. The pain typically appears on day 3 to day 5, increasing rather than decreasing, radiating to the ear and temple, and ordinary painkillers barely touch it. This is dry socket.

The three things that most often dislodge the clot are all within your control: smoking, using a straw, and rinsing vigorously or spitting in the first 24 hours. That is why the seemingly trivial instructions after an extraction matter more than which medication you were prescribed.