Coronectomy
In this section, we will cover:
- What are the risks?
- What is a coronectomy?
Should I have an extraction or coronectomy?
- What is the procedure?
What is a coronectomy?
A coronectomy is a dental procedure in which the crown (white part of the tooth you can usually see above the gum) of a wisdom tooth is removed, leaving the roots buried in the gum.
It is given as an alternative treatment option to having a wisdom tooth removed when the wisdom tooth is close to the inferior dental nerve, as it reduces the risk of nerve damage.
This inferior dental nerve supplies the feeling to your teeth, gums, lip, chin and tongue. Damage to this nerve can cause temporary or permanent loss or altered sensation to these areas. Due to this loss of feeling, speaking and drinking can also be difficult.
There is another nerve (lingual nerve) which runs along the jaw closer to the tongue which allows you to taste food/drink. If this nerve is damaged, it will affect how you are able to taste things.
What are the risks?
- Although the aim of a coronectomy is to leave the roots in the bone, if they become mobile during the procedure then they will need to be removed. This means there is a chance of nerve damage (the same chance as if the tooth was planned for extraction).
- In 15-20% of cases, the roots can become infected after surgery and will need to be removed. By this time, the roots have usually drifted upwards (away from the nerve) which reduces the risk of nerve damage when they are extracted.
- Following a coronectomy, the roots tend to drift up towards the gum. If these emerge through the gum, they may need to be removed. At this point, there is little to no risk of nerve damage as the roots have moved so far away from the nerve.
Should I have an extraction or coronectomy?
This is a question many people ask after an xray or 3D CBCT scan (see here) shows there is a close relation between the roots of their wisdom teeth and the inferior dental nerve.
Extraction
- Whole tooth removed, including roots
- Higher chance of nerve damage (loss/altered sensation to half of lower jaw). In most cases, this damage is temporary and sensation will return within 1 year. In 1% of cases, this damage is permanent.
Coronectomy
- Crown removed, leaving roots buried under the gum
- Reduces risk of nerve damage
- If the roots become infected, you will need a second surgical procedure to remove these.
You need to consider which of these risks will have a bigger negative impact on your life.
You should also ask yourself: how much is the tooth bothering you? If your tooth is not causing you much trouble - say, you get some mild bouts of pericoronitis once or twice a year - you may decide to leave the tooth alone instead of risking nerve damage.
What is the procedure?
This procedure is usually carried out by an oral surgeon or a general dentist with experience carrying out surgical procedures. Often these dentists have spent part of their career working in a hospital. The procedure normally takes 30-45 minutes.
The stages of a coronectomy are similar to a surgical extraction.
Stage 1: Local anaesthetic
Local anaesthetic is a medicine used to numb the tooth and gum. It is given by a small injection next to the tooth. For a lower wisdom tooth, your dentist will also give an injection at the back of the mouth which numbs the teeth, gum, tongue, lip and chin on that side. This will ensure you don't feel any pain during the procedure but you will still feel some pressure.
Stage 2: Lifting the gum
As the tooth is usually only partially erupted (partly hidden under the gum), a small cut is made along the gumline and the gum is lifted away from the tooth. This allows your dentist to see the area more clearly.
Stage 3: Removing bone
Once the gum has been lifted away from the tooth, a small amount of bone is removed just next to the tooth. Your dentist will remove just enough bone to allow them to see the where the crown of the tooth meets the root. There will be a constant cold water spray to keep the drill cool.
Stage 4: Removing the crown
The tooth will be sectioned (or cut) along the junction of the crown and the root. This allows the crown to be lifted away - you will feel some pressure during this part and hear a cracking noise as the crown comes away from the root.
The roots will be smoothed to remove any sharp fragments which can delay healing.
Stage 5: Cleaning and closing the gum
Once the crown is removed and the root smoothed, your dentist will wash the area with a saline solution (salty water). The gum is put back in its natural position and dissolvable stitches placed to allow the area to heal. Most dentists use stitches which dissolve by themselves within 7-14 days.
For aftercare instructions, see here.