The aim of this treatment is to produce ankylosis allowing the tooth to be maintained
as a natural space maintainer, perhaps for a limited period only.
Pulpal and periodontal status in p.d.l. injuries
Pulpal necrosis is the most common complication and is related to the severity of the
periodontal injury (744HTable 12.2). Immature teeth have a better prognosis than mature
teeth due to the wide apical opening where slight movements can occur without
disruption of the apical neurovascular bundle. Necrosis can be diagnosed in most
cases within 3 months of injury but in some cases may not be evident for at least 2
years. A combination of clinical and radiological signs are often required to diagnose
necrosis.
SENSITIVITY TESTING
The majority of injured teeth test negatively to e.p.t. immediately following trauma.
Most pulps that recover test positively within months but responses have been
reported as late as 2 years after injury. A negative test alone therefore should not be
regarded as proof of necrosis. Postpone endodontics until at least one other clinical
and/or radiographic sign is present.
TOOTH DISCOLOURATION
Initial pinkish discolouration may be due to subtotal severance of apical vessels
leading to penetration of haemoglobin from such ruptures into the dentine tubules. If
the vascular system repairs then most of this discolouration will disappear. If the tooth
becomes progressively grey then necrosis should be suspected. A grey colour that
appears for the first time several weeks or months after trauma, signifies
decomposition of necrotic pulp tissue and is a decisive sign of necrosis. Colour
changes are usually most apparent on the palatal surface of the injured teeth.
TENDERNESS TO PERCUSSION
This may be the most reliable isolated indicator of pulpal necrosis.
PERIAPICAL INFLAMMATION
Radiological periapical involvement secondary to pulp necrosis and infection can be
seen as early as 3 weeks after trauma. In mature teeth transient apical breakdown
(t.a.b.) may be mistaken for periapical inflammation and may be present up to 2-3
months after trauma. It represents the response to an ingrowth of new tissue into the
pulp canal.
ARREST OF ROOT DEVELOPMENT
If necrosis involves the epithelial root sheath before root development is complete,
then no further root growth will occur (745HFig. 12.17 (a) and (b)). In an injured pulp
necrosis may progress from coronal to apical portion and hence residual apical vitality
may result in formation of a calcific barrier across a wide apical foramen. Failure of
the pulp chamber and root canal to mature and reduce in size on successive
radiographs compared with contralateral uninjured teeth is also a reliable indicator of
necrosis.