A coronectomy is the removal of only the crown of a particular tooth, typically a wisdom tooth that is below the gums. Over time, wisdom teeth begin to get larger and the roots can grow down into the alveolar nerves in the face. If these nerves are touched during the surgical procedure to remove the entire tooth, complications can arise. For this reason, a coronectomy only removes the crown or top of the wisdom tooth, leaving the roots in place and preventing the likelihood of that nerve being touched.