One of the classic symptoms of irreversible pulpitis is
lingering pain induced by thermal stimuli. Only mild
temperature changes are required to induce the pain
(e.g., tap water, breathing cold air). The initial reaction
is a very sharp pain to hot or cold stimuli and it then
lingers for minutes to hours after the stimulus is
removed. The lingering pain is usually a dull ache or a
throbbing pain. Spontaneous (unprovoked) pain, which
may wake the patient at night and may become worse
when lying down, is another hallmark feature of
irreversible pulpitis. Patients with irreversible pulpitis
often need strong analgesics and may have difficulty
locating the precise tooth that is the source of the pain.
They may even confuse the maxillary and mandibular
arches (but not the left and right sides of the mouth)
because of the extensive branching of dental nerve
axons and perhaps fewer proprioceptive fibres in the
pulp.
Pulps afflicted with irreversible pulpitis without
periapical pathosis may sometimes be difficult to
diagnose; information provided by the patients and the
results of pulp sensibility tests become particularly
helpful in these cases. When the periapical tissues are
involved (Figs 3 and 4), the tooth will usually be tender
to pressure and/or percussion. Dynamic changes occur
in the irreversibly inflamed pulp and it may move from
being chronic and asymptomatic to having acute pain
within a matter of just a few hours.
Acute irreversible pulpitis
Acute irreversible pulpitis usually has a sudden onset
that may wake the patient at night. The pain is
spontaneous with moderate to very severe intensity,
and it lingers in response to temperature changes (heat
and/or cold). The pain may be intensified by posture
changes such as when lying down or bending over.
Common analgesics are rarely effective in controlling
the pain. In most cases, radiographs are not useful in
diagnosis but they can be helpful in identifying the
possible cause of the disease (e.g., deep caries, an
extensive or fractured restoration, pins etc.). The tooth
may be tender to biting pressure and/or percussion and,
if present, this usually indicates spread of the
inflammatory process to the periapical tissues (Figs 3
and 4). In some cases, the biting or percussion pain may
indicate a crack in the tooth (Fig 4) and this is
particularly noticeable when the crack is undermining a
cusp.
Chronic irreversible pulpitis
Chronic irreversible pulpitis will have similar signs
and symptoms but they will be much less severe than
those in the acute cases. Patients may complain of
moderate pain, which is more intermittent rather than
continuous and it may be controlled by common
analgesics. In the early stages of the disease process, the
diagnosis may be difficult because the tooth may not
show any demonstrable periapical change on the
radiographs or a definitive sign of tenderness to
percussion. However, information from the patient and
pulp sensibility tests should be useful. As the disease
progresses to involve the periapical tissues, periapical
changes are more likely to be evident radiographically
and/or clinically