Re: Coronectomy

SPECIFIC TECHNIQUE
The intention of coronectomy or deliberate root retention
is that the part of the root intimately related to
the inferior alveolar nerve is undisturbed. However,
enough of the root must be removed below the crest of
the lingual and buccal plates of bone to enable bone to
form over the retained roots as part of the normal healing
process. It was also felt to be important not to
mobilize the roots because they might damage the nerve
and then become mobile foreign bodies, and for this
reason complete transection of the crown and roots of
the tooth was felt to be necessary.
The technique used is as follows:
1. All patients were placed on appropriate preoperative
prophylactic antibiotics.
2. A conventional buccal flap with releasing incision
was raised, elevated, and retained with a
Minnesota retractor.
3. A lingual flap was raised and the lingual tissues
retracted and an appropriate lingual retractor,
such as a Walter’s lingual retractor,12 was
placed to protect the lingual nerve.
4. Using a 701-type fissure bur, the crown of the
tooth was transected at an angle of approximately
45° (Fig 1). The crown was totally
transected so that it could be removed with
tissue forceps alone and did not need to be
fractured off the roots. This minimizes the
possibility of mobilizing the roots. However,
the lingual retractor is essential during this
technique because the lingual plate of bone
can be inadvertently perforated (Fig 2), and
otherwise the lingual nerve would be at risk.
Following removal of the crown of the tooth,
the fissure bur is used to reduce the remaining
root fragments so that the remaining roots are
at least 3 mm below the crest of the lingual and
buccal plates in all places (this involves removing
the shaded portion in Fig 3).
An alternative technique is to use a round bur
from a superior aspect and remove the crown
and superior part of the roots by drilling it
away. In this case, only minimal lingual retraction
may be required.
5. There is no attempt at root canal treatment or
any other therapy to the exposed vital pulp of
the tooth.
6. Following a periosteal release, a watertight primary
closure of the socket is performed with 1
or more vertical mattress sutures.