Adults can have up to 32 teeth.  The wisdom teeth are the last to come through, right at the back.  They usually appear when you are between 17 and 25, although sometimes they appear many years later.Nowadays people often have jaws that are too small for all 32 teeth – 28 is often the most we have room for.  So if all the other teeth are present and healthy there may not be enough space for the wisdom teeth to come through properly.Tooth extraction is the removal of a tooth from its socket in the bone. The teeth, which have been damaged by decay or fracture, will be repaired and restored with a filling, crown or other treatment by the dentist. But sometimes if the damage is too extensive, the teeth cannot be repaired. Then it is necessary to do the extraction.