Some wisdom teeth erupt normally and become useful teeth.
Often, there is insufficient space for the wisdom teeth to erupt properly, and they become impacted.
Impacted teeth can be a source of infection, especially when they are partially erupted, with part of the tooth having broken out of the bone. These infections can vary from very mild, lasting only a few days, to life-threatening infections that can require immediate surgical intervention.
Impacted wisdom teeth can also damage the teeth into which they are impacting.
Some wisdom teeth can be safely removed in the dental chair under local anaesthetic. The more severely impacted teeth and teeth that appear to be very close to the nerve in the bone are usually referred to a maxillo-facial oral surgeon for extraction, often under general anaesthetic.
With every extraction of a lower wisdom tooth there is potential risk of injury to the nerve. This injury may be as mild as ‘bruising’ of the nerve resulting in some altered sensation than might last from a few hours to a few months or the nerve can be severed or crushed resulting in permanent numbness of the lower lip on that side. Fortunately, such misfortunes are extremely rare.
Not all impacted wisdom teeth have to be removed, especially those which have not penetrated out of the bone at all.