Coronectomy of lower wisdom teeth

diversion of canal coronectomy

Coronectomy of wisdom teeth

Coronectomy is the removal of the top half of a tooth, thus leaving the bottom portion in the jaw. In other words it is the surgical removal of the top half of the tooth (all enamel), allowing the bottom half that is near the nerve to stay in place.

Why would we do a coronectomy?

With the advent and much more common use of CBCT dentists can have a much more accurate view of the proximity of lower wisdom teeth to the Inferior Alveolar Nerve.  With this knowledge we can more precisely evaluate the risk of nerve damage from removal.  When we deem the risk for injury as moderate or higher, we may recommend a coronectomy.  A new 3 year study Leung 2012 on this procedure has shown it to be very successful and I feel very comfortable recommending patients to do this if their wisdom teeth do not have an infection in the bone and are close to the nerve.  More info Ahmed 2011

What teeth can not get a coronectomy?

Typically we only do a coronectomy on wisdom teeth as they are the teeth that cause IAN problems.

Reasons to NOT do a coronectomy.

  • Roots are not touching or in very close proximity to the nerve
  • Teeth with apical or periodontal infection or decay into the pulp
  • Pre-existing numbness of the IAN
  • Pre-existing mobility of the tooth

Steps for a wisdom tooth coronectomy

Section the coronal portion of the tooth. Remove all enamel, as retention of enamel is associated with higher failure rate. Remove tooth structure 3-4mm below bone crest.

What are the risks of nerve injury during wisdom tooth removal?

If the tooth is in close association with the IAN canal radiographically, 20% of patients are at risk of developing temporary IAN nerve injury and 1‑4% are at risk of permanent injury.  Radiographic signs indicative of possible IAN risk include: Renton 2012

  • Diversion of the canal

Diversion of IAN canal

  • Darkening of the root
  • Narrowing of the root/canal
  • Interruption of the canal lamina dura
  • Interruption of the juxta‑apical area
Reasons to do a coronectomy
Rood and Shehab classification from 1990 article

What is the research say on coronectomy procedures?

Systemic Review Long 2012 talks about risk.  Another systemic review Ghaeminia 2013 =same

What is the typical outcome with this type of extraction and what does a failure look like?

Some of these roots later erupted, but they erupt up and away from the nerve so they can then be safely removed. A failure will result in pain as the body tries to expel the partial piece of tooth. In my experience going back in at a slightly later date (weeks later) results in a root fragment that is much easier to remove. This is do to the fact that the body attempts removal through soft tissue encapsulation.

What is the ADA dental code for a coronectomy – intentional partial tooth removal.

The dental code for coronectomy is D7152. Coronectomy is the intentional partial tooth removal performed when a neurovascular complication is likely if the entire impacted tooth is removed.

What is the cost of a coronectomy?

Check out fair health consumer for fees for a given zip code. We charge around $800 in 2021.