A dentist usually advises wisdom tooth extraction if you experience symptoms like pain, infection of the bone behind the lower last tooth, cysts, gum disease, severe tooth cavity, damage to adjacent teeth or tumour.
The eruption of a wisdom tooth is very often a slow process where the tooth can only partially penetrate the gum and remain at this stage for a long time. This, in turn, creates the precondition for subsequent problems, as a gingival pocket forms around the erupted tooth. This makes the cleaning of the tooth difficult and leads to the accumulation of bacteria, and at a later stage to inflammation.
There can also be a problem when the wisdom teeth are in the wrong position and interfere with the remaining teeth. The wisdom tooth can be located horizontally, "lying" on the nearby molar tooth, or to be located inwards to the oral cavity or outwards to the cheek. In these cases, the wisdom tooth needs to be removed.
In a normally erupted wisdom tooth, the extraction proceeds as in any normal tooth. But when it is partially erupted or not erupted at all (it is inside the bone), then surgery is more complicated. In this case, your dentist may also refer you to a dental surgeon.
It may not be necessary to remove your wisdom teeth if they are positioned correctly at the back of your mouth, if they are healthy, fully erupted and in case cleaning is easily performed in daily hygiene practices.