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| Coronectomy / Intentional Partial Odontectomy |
Coronectomy is the removal of the crown of a
tooth, leaving the roots in situ.
When applied to a lower wisdom tooth or any lower un-
erupted posterior tooth, it is a measure adopted to avoid
damage to the Inferior Alveolar Nerve (IAN) (the nerve that
supplies feeling / sensation to the lip and chin) when the X-
ray has suggested an intimate relationship between the
roots of the lower wisdom tooth and the IAN and the tooth
still needed to be removed.
The expectation after removing the top of the tooth is that
the roots will remain in place and eventually cover with
bone.
Roots encased in bone can remain buried in the jaw for
years and rarely cause problems.
Coronectomy of lower molars is NOT carried out in the
following situations:
tooth, leaving the roots in situ.
When applied to a lower wisdom tooth or any lower un-
erupted posterior tooth, it is a measure adopted to avoid
damage to the Inferior Alveolar Nerve (IAN) (the nerve that
supplies feeling / sensation to the lip and chin) when the X-
ray has suggested an intimate relationship between the
roots of the lower wisdom tooth and the IAN and the tooth
still needed to be removed.
The expectation after removing the top of the tooth is that
the roots will remain in place and eventually cover with
bone.
Roots encased in bone can remain buried in the jaw for
years and rarely cause problems.
Coronectomy of lower molars is NOT carried out in the
following situations:
- Wisdom tooth roots are not touching the IAN canal
- Wisdom tooth with either active root tip or crown
infection - Pre-existing numbness of the IAN
- Pre-existing mobility of the tooth as any retained roots
may act as a mobile foreign body and become a nidus
for infection / migration. - Teeth that are horizontally impacted along the course
of the IAN as sectioning the tooth crown could
endanger the IAN. - Systemic condition predisposing to local infection such
as diabetes, AIDS and concurrent chemotherapy. - Local factors predisposing to infection such as
metabolic bone diseases (e.g. fibrous dysplasia),
history of radiotherapy to the lower jaw.
This list of warnings might seem excessive to some
however the legal ruling in the case of Chester vs Afshar
(2004) would suggest that it is quite prudent / necessary to
list them. Others might say that there isn't enough
information but where do you stop?
The following list of warnings regarding coronectomy is
neither exhaustive nor is it predictive. You are to have a
tooth decoronated.
You can expect the following:
Coronectomy / Intentional Partial Odontectomy
Specific Warnings:
Antibiotics (pre- & post-op). These are recommended to
lower the chance of infection either in the socket or the
tooth pulp. These will be given at the clinicians’ discretion.
Primary Closure. The retained roots are covered over by
the gum to facilitate healing of the pulp, socket and to
lessen the chance of operation site infection.
Root Canal Treatment of retained roots is not necessary.
Osteo-cementum Growth. The root margins are trimmed
several millimetres below the crest of the socket to
encourage bone & osteo-cementum formation over the
retained roots, sealing off the roots from the mouth.
Roots inadvertently removed at the time of attempted
coronectomy. When it came to removing the crown, it was
found that the roots as well were mobile. This ranges from
3 - 9%. If the roots are mobile, we are obliged to remove
them and there is obviously the risk to the IAN (which this
procedure was trying to avoid).
Numbness of Chin, Lip ± Tongue. The Inferior Alveolar &
Lingual Nerves may still be damaged during the procedure
resulting in numbness affecting the tongue +/- the chin and
lower lip. The numbness of the tongue seems to be quite
short-lived and has a low incidence. The numbness of the
chin ± lip tended to occur when on attempting the
coronectomy, the roots were found to be mobile and had
to be removed.
Root Migration. Subsequent migration of the roots away
from the IAN occurred in 14 - 81% of cases.
Later Removal of Roots. This can happen in up to a 2 -
6% of cases. If the roots irritate overlying tissues or the
adjacent tooth or otherwise become symptomatic, they
may need to be removed. Even though a 2nd surgery
would be needed, the possibility of nerve damage should
be negligible since the roots would have migrated away
from its original resting place next to the IAN. Since the
purpose of the coronectomy is to avoid this damage, this
goal would have been accomplished even though a 2nd
surgical procedure was necessary to remove the remaining
root.
General Surgical Warnings:
Pain. As it is a surgical procedure, there will be soreness
after the tooth removal. This can last for several days.
Painkillers such as ibuprofen, paracetamol, Solpadeine or
Nurofen Plus are very effective. Obviously, the painkiller
you use is dependent on your medical history & the ease of
the operation.
Swelling. There will be swelling afterwards. This can last
up to a week. Use of an icepack or a bag of frozen peas
pressed against the cheek adjacent to the tooth removed
will help to decrease the swelling. Avoidance in the first
few hours post-op, of alcohol, exercise or hot foods/drinks
will decrease the degree of swelling that will develop.
Bruising & Bleeding into Cheeks. Some people are prone
to bruise. Older people, people on aspirin or steroids will
also bruise that much more easily. The bruising can look
quite florid; this will eventually resolve but can take several
weeks (in the worst cases).
Swelling that does not resolve within a few days may be
due to bleeding into the cheek. The cheek swelling will feel
quite firm. Coupled with this, there may be limitation to
mouth opening and bruising. Both the swelling, bruising
and mouth opening will resolve with time.
Stitches. The coronectomy site will often be closed with
stitches. These dissolve and will ‘fall out’ within 10 – 14
days.
Limited Mouth Opening. Often the chewing muscles and
the jaw joints are sore after the procedure so that mouth
opening can be limited for the next few days. If you are
unlucky enough to develop an infection afterwards in the
socket, this can make the limited mouth opening worse and
last for longer (up to a week or so).
Post-op Infection. You may develop an infection in the
socket after the operation. This tends to occur 2 – 4 days
later and is characterised by a deep-seated throbbing pain,
bad breath and an unpleasant taste in the mouth. This
infection is more likely to occur if you are a smoker, are on
the contraceptive pill, on drugs such as steroids and if bone
has to be removed to facilitate tooth extraction.
If antibiotics are given, they are likely to react with alcohol
and / or the Contraceptive Pill (that is, the ‘Pill’ will not be
providing protection).
Surrounding Teeth. The surrounding teeth may be sore
after the extraction; they may even be slightly wobbly but
the teeth should settle down with time. It is possible that
the fillings or crowns of the surrounding teeth may come
out, fracture or become loose. If this is the case, you will
need to go back to your dentist to have these sorted out.
Every effort will be made to make sure this doesn’t
happen. In very rare instances, the surrounding teeth may
actually come out as well as the intended tooth.
Failure of Anaesthesia. In rare cases, the tooth can be
difficult to ‘numb up’. This can be due to a number of
reasons. The more common ones include inflammation ±
infection associated with the tooth, anatomical differences
& apprehension. If the tooth fails to ‘numb up’ then its
removal will be rescheduled with antibiotic cover or
perhaps done under sedation or even a GA.
Useful Articles:
Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004.
Coronectomy (Intentional Partial Odontectomy of Lower
Third Molars)
J Oral Maxillofac Surg 2004. Coronectomy: A Technique
to Protect the Inferior Alveolar Nerve
International Dentistry. Coronectomy - An Alternative
Therapy for the symptomatic impacted 3rd molar - Report
of 9 cases
British J Oral Maxillofac Surg 2006. Is Coronectomy
Really Preferable to Extraction?
J Oral Maxillofac Surg 2009. Clinical Evaluations of
Coronectomy (Intentional Partial Odontectomy) for
Mandibular Third Molars Using Dental Computed
Tomography - A Case-Control Study
Oral Surgery, Oral Medicine, Oral Pathology,Oral
Radiology, and Endodontology 2009. Safety of
coronectomy versus excision of wisdom teeth - a
randomized controlled trial
Oral Surgery 2010. A Review of Coronectomy
British Dental Journal 2010. Coronectomy – Oral Surgery’s
answer to modern-day conservative dentistry
Dental Update 2010. Coronectomy of a 3rd Molar with
Cyst Lining Enucleation in the Management of a
Dentigerous Cyst
Dental Update 2011. Coronectomy of Third Molar. A
Reduced Risk Technique for Inferior Alveolar Nerve
Damage
JOMS 2011. Coronectomy in Patients With High Risk of
Inferior Alveolar Nerve Injury Diagnosed by Computed
Tomography
BDJ 2012. Notes on Coronectomy
however the legal ruling in the case of Chester vs Afshar
(2004) would suggest that it is quite prudent / necessary to
list them. Others might say that there isn't enough
information but where do you stop?
The following list of warnings regarding coronectomy is
neither exhaustive nor is it predictive. You are to have a
tooth decoronated.
You can expect the following:
Coronectomy / Intentional Partial Odontectomy
Specific Warnings:
Antibiotics (pre- & post-op). These are recommended to
lower the chance of infection either in the socket or the
tooth pulp. These will be given at the clinicians’ discretion.
Primary Closure. The retained roots are covered over by
the gum to facilitate healing of the pulp, socket and to
lessen the chance of operation site infection.
Root Canal Treatment of retained roots is not necessary.
Osteo-cementum Growth. The root margins are trimmed
several millimetres below the crest of the socket to
encourage bone & osteo-cementum formation over the
retained roots, sealing off the roots from the mouth.
Roots inadvertently removed at the time of attempted
coronectomy. When it came to removing the crown, it was
found that the roots as well were mobile. This ranges from
3 - 9%. If the roots are mobile, we are obliged to remove
them and there is obviously the risk to the IAN (which this
procedure was trying to avoid).
Numbness of Chin, Lip ± Tongue. The Inferior Alveolar &
Lingual Nerves may still be damaged during the procedure
resulting in numbness affecting the tongue +/- the chin and
lower lip. The numbness of the tongue seems to be quite
short-lived and has a low incidence. The numbness of the
chin ± lip tended to occur when on attempting the
coronectomy, the roots were found to be mobile and had
to be removed.
Root Migration. Subsequent migration of the roots away
from the IAN occurred in 14 - 81% of cases.
Later Removal of Roots. This can happen in up to a 2 -
6% of cases. If the roots irritate overlying tissues or the
adjacent tooth or otherwise become symptomatic, they
may need to be removed. Even though a 2nd surgery
would be needed, the possibility of nerve damage should
be negligible since the roots would have migrated away
from its original resting place next to the IAN. Since the
purpose of the coronectomy is to avoid this damage, this
goal would have been accomplished even though a 2nd
surgical procedure was necessary to remove the remaining
root.
General Surgical Warnings:
Pain. As it is a surgical procedure, there will be soreness
after the tooth removal. This can last for several days.
Painkillers such as ibuprofen, paracetamol, Solpadeine or
Nurofen Plus are very effective. Obviously, the painkiller
you use is dependent on your medical history & the ease of
the operation.
Swelling. There will be swelling afterwards. This can last
up to a week. Use of an icepack or a bag of frozen peas
pressed against the cheek adjacent to the tooth removed
will help to decrease the swelling. Avoidance in the first
few hours post-op, of alcohol, exercise or hot foods/drinks
will decrease the degree of swelling that will develop.
Bruising & Bleeding into Cheeks. Some people are prone
to bruise. Older people, people on aspirin or steroids will
also bruise that much more easily. The bruising can look
quite florid; this will eventually resolve but can take several
weeks (in the worst cases).
Swelling that does not resolve within a few days may be
due to bleeding into the cheek. The cheek swelling will feel
quite firm. Coupled with this, there may be limitation to
mouth opening and bruising. Both the swelling, bruising
and mouth opening will resolve with time.
Stitches. The coronectomy site will often be closed with
stitches. These dissolve and will ‘fall out’ within 10 – 14
days.
Limited Mouth Opening. Often the chewing muscles and
the jaw joints are sore after the procedure so that mouth
opening can be limited for the next few days. If you are
unlucky enough to develop an infection afterwards in the
socket, this can make the limited mouth opening worse and
last for longer (up to a week or so).
Post-op Infection. You may develop an infection in the
socket after the operation. This tends to occur 2 – 4 days
later and is characterised by a deep-seated throbbing pain,
bad breath and an unpleasant taste in the mouth. This
infection is more likely to occur if you are a smoker, are on
the contraceptive pill, on drugs such as steroids and if bone
has to be removed to facilitate tooth extraction.
If antibiotics are given, they are likely to react with alcohol
and / or the Contraceptive Pill (that is, the ‘Pill’ will not be
providing protection).
Surrounding Teeth. The surrounding teeth may be sore
after the extraction; they may even be slightly wobbly but
the teeth should settle down with time. It is possible that
the fillings or crowns of the surrounding teeth may come
out, fracture or become loose. If this is the case, you will
need to go back to your dentist to have these sorted out.
Every effort will be made to make sure this doesn’t
happen. In very rare instances, the surrounding teeth may
actually come out as well as the intended tooth.
Failure of Anaesthesia. In rare cases, the tooth can be
difficult to ‘numb up’. This can be due to a number of
reasons. The more common ones include inflammation ±
infection associated with the tooth, anatomical differences
& apprehension. If the tooth fails to ‘numb up’ then its
removal will be rescheduled with antibiotic cover or
perhaps done under sedation or even a GA.
Useful Articles:
Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004.
Coronectomy (Intentional Partial Odontectomy of Lower
Third Molars)
J Oral Maxillofac Surg 2004. Coronectomy: A Technique
to Protect the Inferior Alveolar Nerve
International Dentistry. Coronectomy - An Alternative
Therapy for the symptomatic impacted 3rd molar - Report
of 9 cases
British J Oral Maxillofac Surg 2006. Is Coronectomy
Really Preferable to Extraction?
J Oral Maxillofac Surg 2009. Clinical Evaluations of
Coronectomy (Intentional Partial Odontectomy) for
Mandibular Third Molars Using Dental Computed
Tomography - A Case-Control Study
Oral Surgery, Oral Medicine, Oral Pathology,Oral
Radiology, and Endodontology 2009. Safety of
coronectomy versus excision of wisdom teeth - a
randomized controlled trial
Oral Surgery 2010. A Review of Coronectomy
British Dental Journal 2010. Coronectomy – Oral Surgery’s
answer to modern-day conservative dentistry
Dental Update 2010. Coronectomy of a 3rd Molar with
Cyst Lining Enucleation in the Management of a
Dentigerous Cyst
Dental Update 2011. Coronectomy of Third Molar. A
Reduced Risk Technique for Inferior Alveolar Nerve
Damage
JOMS 2011. Coronectomy in Patients With High Risk of
Inferior Alveolar Nerve Injury Diagnosed by Computed
Tomography
BDJ 2012. Notes on Coronectomy
| Last Updated 7th September 2012 |