Monday, September 15, 2014

An overview of the dental pulp: its functions and responses to injury

The dental pulp is a unique tissue and its importance
in the long-term prognosis of the tooth is often
ignored by clinicians. It is unique in that it resides in
a rigid chamber which provides strong mechanical
support and protection from the microbial rich oral
environment. If this rigid shell loses its structural
integrity, the pulp is under the threat of the adverse
stimuli from the mouth, such as caries, cracks,
fractures and open restoration margins, all of which
provide pathways for micro-organisms and their
toxins to enter the pulp. The pulp initially responds
to irritation by becoming inflamed and, if left
untreated, this will progress to pulp necrosis and
infection. The inflammation will also spread to the
surrounding alveolar bone and cause periapical
pathosis. The magnitude of pulp-related problems
should not be underestimated since their most
serious consequence is oral sepsis, which can be life
threatening, and hence correct diagnosis and
management are essential. Clinicians must have a
thorough understanding of the physiological and
pathological features of the dental pulp as well as the
biological consequences of treatment interventions.
Key words: Dental pulp, pulp disease, inflammation,
necrosis.


Abbreviations and acronyms: CGRP = calcitonin gene-related
peptides; IL = interleukins; PBF = pulp blood flow;
SP = substance P; TTXr = tetrodotoxin-resistant; TTXs =
tetrodotoxin-sensitive
The dental pulp resides in a rigid chamber comprising
dentine, enamel and cementum, which provide strong
mechanical support and protection from the microbial
rich oral environment. However, if this rigid shell loses
its structural integrity, the pulp is under the threat of
the adverse stimuli from the mouth. Caries, cracks,
fractures and open restoration margins provide
pathways for micro-organisms and their toxins to enter
the pulp. The response of the pulp to irritation is
inflammation and, if unattended, this will eventually
progress to pulp necrosis. Inflammation may spread to
the surrounding alveolar bone and cause periapical
pathosis. The magnitude of pulp-related problems
should not be underestimated. The most serious
consequence of pulp disease is oral sepsis, which can be
life threatening.
If the infection spreads from the
maxillary teeth, it may cause purulent sinusitis,
meningitis, brain abscess, orbital cellulitis and
cavernous sinus thrombosis, whereas infection from the
mandibular teeth may cause Ludwig’s angina,
parapharyngeal abscess, mediastinitis, pericarditis,
emphysema and jugular thrombophlebitis. Moreover,
the number of teeth that are extracted result in
mutilated dentitions, malnutrition and possible
emotional problems.
Toothache is a common complaint in the dental
clinic, and yet diagnosis of pulp disease is often difficult
due to the seemingly unclear symptoms and the
inaccessibility of the pulp for clinical tests. This is further
complicated by referred toothache originating from the
tissues other than the pulp. Improper diagnosis can lead
to improper treatment, causing distress to the patient
and embarrassment to the practitioner. An understanding
of the histophysiology of the healthy pulp and the
possible underlying pathological processes in the
diseased pulp, careful assessment of the pain history,
and appropriate clinical examination and diagnostic
tests, should aid the dental practitioner in reaching an
accurate diagnosis and a positive treatment outcome.