Fracture / Failure of Instrument with Retention of
Instrument Fragment
within Bone / Soft Tissue
Any broken instrument should be removed at the time of the operation.  If not
retrievable, the patient should be told and this recorded in the notes.

Suture needles, hypodermic needles and surgical burrs are the items that most
frequently fracture / fail in use.  
Suture needles are probably the commonest items
to be broken during minor oral surgery.
As a general rule, all fragments of broken instruments should be removed
immediately before they have time to migrate deeper into the tissues.

If the fragment cannot be found, radiographs in 2 planes at 90° should be taken of
the operative area to locate it.  At this point, a decision will need to be taken as to
whether to remove the fragment or leave it in situ depending on its size and site.
Broken fissure bur (arrowed) in tissues which occurred during the surgical removal
of an impacted lower 3rd molar
Broken round bur (surgical drill) and sub-periosteal dislocation of the bur which
occurred during surgical extraction
Small fragments lying sub-periostealy can be safely left as knowledge of the local
anatomy is essential if further complications are to be avoided.  It should be
remembered that small fine foreign bodies can be extremely difficult to locate and
that blind exploration of tissue spaces is wont to displace them deeper.  The use
of image intensification can be very helpful in this situation.

Breakage of an instrument in the tissues is the result of excessive force during the
removal of the tooth and usually involves the end of the blade of various elevators
or of the instrument altering its metallic composition (mainly of the bur).  In these
cases, after precise radiographic localisation, the broken piece(s) are removed
surgically at the same time as extraction of the tooth or root.
Last Updated 20th May 2015
Useful Articles:

Am J Neuroradiol 1998.  Dental Bur Fragments Causing Metal Artifacts

Dental Update 2009.  Fracture of a Dental Needle during Administration of an
Inferior Alveolar Nerve Block.

J Can Dent Assoc 2011.  Management of a Broken Needle in the
Pterygomandibular Space Following a Vazirani-Akinosi Block: Case Report

Dental Update 2015.  Case Report. Fractured Needle in the Pterygomandibular