When a tooth doesn't fully grow in, it's "impacted" This means the tooth is unable to break through the gums because there isn't enough room.
An impacted wisdom tooth can damage neighboring teeth or become infected. Because it's in an area that’s hard to clean, it can also invite bacteria that lead to gum disease. Oral bacteria can also travel through your bloodstream and lead to infections and illnesses that affect your heart, kidneys and other organs. In some cases, a cyst or tumor can form around the base of the impacted tooth, which can lead to more serious problems as it hollows out the jaw and damages surrounding nerves, teeth and other parts of your mouth and face.
Wisdom teeth should be removed if they are:
Infections and/or periodontal (gum) disease
Cavities that can’t be restored
Cysts, tumors or other pathologies
Damage to neighboring teeth