Coronectomy /
Intentional Partial Odontectomy
(Partial Root Removal,
Deliberate Vital Root Retention
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 procedure used 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 (the intimacy
of the tooth roots to the nerve canal can be confirmed with
the use of a Cone Beam CT scan [CBCT]).

The expectation, after removing the top of the tooth, is that
the roots will remain in place and eventually sealed with

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 infection or
    decay in the crown of the tooth (which extends to the

  • Active periodontal disease in the region of the wisdom
    tooth and the tooth in front of the wisdom tooth

  • 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 chemo-therapy /

  • Local factors predisposing to infection such as
    metabolic bone diseases (e.g. fibrous dysplasia),
    history of radio-therapy to the lower jaw

  • Where it would not be possible to remove all the
    enamel (retention of enamel seems to be associated
    with a higher failure rate)

  • Where the 2nd molars will be moved distally in
    orthodontic treatment or orthognathic surgery on the
    mandible is being considered.

  • Where the tooth is associated with tumours or large
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:

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).  This is more likely to happen if the roots are conical in shape.

Incomplete Crown Removal (link to annotated picture).  Not being able to visualize
the root surface is a common problem with disto-angular impactions and makes
root finishing difficult. This may mean that all the enamel has not been removed.  
Retained enamel or spicules of enamel can cause irritation to the overlying gum or,
as the enamel acts as foreign body, increases the chances of infection of the
unhealed socket.

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

Root Migration (link to annotated picture). Subsequent migration of the roots
away from the
IAN occurred in 14 - 81% of cases.  The roots seem to move the
most during the first 6 months post-
coronectomy, with a typical distance of 2 -
3mm away from the
IAN.  Root migration halts as the bone regenerates and

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
paracetamol, Solpadeine or Nurofen Plus are very effective.  Obviously, the
painkiller you use is dependent on your medical history & the ease of the
operation.  The pain can take awhile to settle down - it is not so much the pain of
a tooth extraction but of a tooth that has been irreversibly traumatised and the
tooth's pain is that of the tooth dying - this can be prolonged.

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
coronectomy site 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, 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 coronectomy;
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 /
Oral Surgeon to have these sorted out.  Every effort will be made to make sure
this doesn’t happen.

Damage to the lower 2nd molar (that is, the tooth in front of the wisdom tooth) has
been reported, which likely occurs when removing all enamel from mesio-angular
impacted wisdom teeth and there is limited access and visibility of the operation

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 & YouTube Link:

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

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

JOMS 2012.  Coronectomy of the Lower 3rd Molar is Safe within the 1st 3 Years

Atlas Oral Maxillofacial Surg Clin N Am 2013.  Coronectomy.  Indications,
Outcomes & Description of Technique

Dental Update 2013.  To Retrieve or not to Retrieve the Coronectomy Root - The
Clinical Dilemma

Dental Update 2013.  Update on Coronectomy.  A Safer Way to Remove High
Risk Mandibular 3rd Molars

Case Reports in Dentistry 2013.  Modified & Grafted Coronectomy - A New
Technique & a Case Report with 2-Year Follow up

JADA 2013.  Coronectomy is an effective strategy for treating impacted 3rd
molars in close proximity to the inferior alveolar nerve

Naval Postgraduate Dental School 2014.  Clinical Update.  Guidelines for Surgical

J Oral Maxillofac Res 2015.  Coronectomy of Deeply Impacted Lower 3rd Molar -
Incidence of Outcomes & Complications after One Year Follow-Up

Dental Update 2015.  Coronectomy – Good or Bad?

Int J Oral Maxillofac Surg. 2015.  Usefulness of mandibular 3rd molar
coronectomy assessed through clinical evaluation over 3 years of follow-up

Med Oral Patol Oral Cir Bucal. 2015.  Coronectomy vs. Surgical Removal of the
Lower 3rd Molars with a High Risk of Injury to The Inferior Alveolar Nerve.  A
Bibliographical Review

BDJ 2016.  Lower Third Molar Surgery – Consent & Coronectomy

J Clin & Diag Res 2016.  Evaluation of Outcome Following Coronectomy for the
Management of Mandibular 3rd Molars in Close Proximity to Inferior Alveolar Nerve

Oral Surg Oral Med Oral Pathol Oral Radiol 2016.  Long-Term Morbidities of
Coronectomy on Lower 3rd Molar

BJOMS 2017.  Life threatening complications of coronectomies

Maxillofacial Plastic & Reconstructive Surgery 2017.  Intentional Partial
Odontectomy - A Long Term Follow-Up Study

YouTube Link (Mr Chris Sproat at 2013 BAOMS Conference talking about
Last Updated 2nd October 2018