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 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
- Darkening of the root
- Narrowing of the root/canal
- Interruption of the canal lamina dura
- Interruption of the juxta‑apical area
What is the research say on coronectomy procedures?
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.