Trauma from accidents or bruxism may cause pulp
inflammation. Crown fractures may provide a pathway
for microbial invasion
which can lead to pulp necrosis
and infection of the root canal system. Root fractures
affect the pulp differently since they may disrupt the
pulp vascular supply within the portion of the tooth
that is coronal to the fracture line and this can lead to
necrosis of the pulp in that segment of the tooth.
However, the rate of survival of the pulp following root
fractures is high and the pulp can initiate a callus-like
form of healing at the fracture site, especially in
immature teeth. Impact trauma may squash the blood
vessels at the apex of tooth and cause temporary
disruption of blood flow, resulting in vascular stasis
with subsequent development of hypoxia and
ischaemia. However, a young tooth with a wide apical
foramen may recover by re-establishing blood flow.
Severe impact (such as intrusion) may destroy the pulp
vessels at the apical foramen and lead to pulp necrosis.
However, depending on the severity of the impact, the
age of the patient and the prior health status of the
pulp, revascularization may occur, especially in
immature teeth. This usually results in calcification of
the root canal in the longer term but occasionally
internal resorption has been observed.
Trauma from occlusion can play a role in the
initiation and progression of pulp inflammation,
how-ever the inflammatory changes tend to be transient.