November 26, 2021
Every tooth has the same basic anatomy, with a crown that is visible above the gum line and roots below to anchor the tooth to the jawbone. Teeth in the front of the mouth have one root, with more roots per tooth moving back to the molars. When attached to a healthy tooth, root tips cause no problems whatsoever. But if a tooth is lost or fractured through trauma or decay, fragments of the root or roots may be retained in the jawbone. It is even more common for molars because they can have up to four tooth roots. If a root tip fracture occurs, the clinician must decide to either leave it or attempt removal. Here is what patients need to know about retained tooth roots and treatment options.
Do tooth roots have to be removed?
In the 1920s, there was a common consensus among clinicians that during extraction the entire crown-root complex should be removed. Anything less was seen as a disservice to the patient. Much like an impacted tooth, a retained tooth root can put a patient at risk of pain, infection, abscess, or cyst development. Retained tooth roots can develop into a bone spur or complicate the fabrication and comfort of restorations like bridges, dentures, and implants.
That said, retained root fragments do not always implicate a negative outcome. Several studies have shown the majority of vital root fragments cause no harm and can remain situated in their original position with normal healing taking place. The fragment may be naturally extruded or it can become entirely enclosed within the bone.
This knowledge led to the research and development of decoronation and submerged-root concepts. For these procedures, the crown of a healthy tooth can be removed from the roots as a way to preserve alveolar bone and prevent alveolar nerve injury. And in suitable patients, the submergence of vital roots can help maintain alveolar bone width and height for prosthodontic purposes or future implant placement.
Should the dentist retain or remove root fragments?
Retained tooth roots are either found incidentally on x-rays or are fractured during extraction procedures. But the decision to remove retained root fragments needs to be made on a case-by-case basis. The length, position, mobilization, and pulpal status of the retained root along with an adequate closure of the socket margins all contribute to the possible outcome.
Where the fragment is closer to the surface, the epithelium often extrudes the bony fragments until they become externalized. In these cases, the sites usually heal well, but take longer than empty sockets. Instead of simply waiting it out, the dentist can surgically remove the root fragment to reduce the risk of an uncomfortable bone spur and promote faster healing.
And where a vital root fragment is embedded more deeply, it can heal and become completely enclosed in a layer of cementum and bone. Factors that allow for successful healing include the vitality of the pulp, little to no mobilization of the fractured root, and a complete wound closer to avoid communication with the oral cavity. These cases are often closely monitored with more frequent exams and radiographs.
But deeper, non-vital fragments, or those communicating with the oral cavity tend to be more serious. With deeper fragments, the epithelium is often unable to extend completely under the root tip and the fragment is not externalized. Instead, the necrotic and inflammatory tissue remains in the socket and will often develop an infection or an abscess. These types of root fragments should be removed before other complications arise.
What are the symptoms of an infected tooth root?
An infected or necrotic tooth root needs to be removed as soon as possible. Symptoms to watch for include:
Frequent jaw pain
Bitter taste in the mouth
Swelling on the side of the gums
Redness, swelling, or drainage at the site
How are retained tooth roots removed?
The surgical extraction of a retained tooth root is relatively straightforward and minimally invasive. First, the dentist will use a local anesthetic to numb the area. More anxious patients might require the use of nitrous oxide to help reduce stress and make the procedure more comfortable. When the patient is numb and sedated, the dentist will make an incision in the gums to create a surgical flap where the dentist can gain access to the bone. With a surgical handpiece, the dentist will gently layer away some of the bone to get full access to the residual root. Depending on the size and location, the dentist will then remove the entire root tip as a whole or segment it off and remove it piece by piece. Once the dentist has removed the root tip they may conduct a socket graft or simply sterilize the site and allow the gum to heal. Then the patient will consult with the dentist about the best type of restoration to replace the missing tooth and prevent bone resorption.