A toothache that brings a patient to the dental office may either be inflammation of the dental pulp or when the pulp is already dead (necrotic). Although lack of pain does not represent a healthy pulp. Pulpal pain symptoms occur with different intensities, e.g. mild, moderate, or severe which is governed by frequency of firing, number of nerves and type of nerve fibres.
A-delta fibers are fast-conducting and evoke a rapid, sharp, lancinating pain reaction, and C-fibers are slow-conducting and cause a slow, dull, crawling pain. C-fibers have a higher excitability threshold than the A-delta fibers. A-delta fibers are located the periphery of the pulp, mostly at the coronal portion, and C-fibers are found centrally in the pulp proper.
Severity and duration of pain is related to the status of pulp pathosis.
Pulp inflammation may be reversible (reversible pulpitis) or irreversible (irreversible pulpitis). Information provided by the patient on nature of pain is important to differentiate between reversible pulpitis and irreversible pulpitis. Standard dental procedures on a tooth with reversible pulpitis is expected to reverse the inflammation of the pulp to a healthy state, whereas tooth with irreversible pulpitis will require an aseptic removal of the entire pulp (root canal treatment).
Symptoms associated with reversible pulpitis: No pain or sharp pain (mild) on contact with cold/hot liquid or sugary substances. Pain goes away when stimulant is removed. Peripheral A-delta fibers are stimulated.
Symptoms associated with irreversible pulpitis: No pain or pain on contact with cold and especially hot liquid, relieved by cold liquid. Pain is severe, throbbing, spontaneous, lingering and wakes the pain from sleep at night. There is usually a past history of pain and severe pain that is difficult to locate accurately (referred pain). The centrally located C-fibers are involved with these pain symptoms.
At this stage, the dentist should have an idea of the diagnosis of the tooth in question. The subsequent step is to determine the tooth that caused pain. A series of test that follows (cold test, heat test and electric pulp test) will determine whether the tooth is alive (vital) or dead (necrotic). These test are rather subjective and are not sensitive to differentiate between reversible pulpitis and irreversible pulpitis. One study shows that 83% of the teeth with a necrotic pulp were identified as necrotic by the cold test, while 93% of the teeth with vital pulp were identified as vital by the cold test. 86% of the teeth with necrotic pulp were identified as non vital by the heat test, while only 41% of the vital teeth were identified as vital by the heat test. For the Electric Pulp Test 72% of the teeth with necrotic pulp were identified as non vital, while 93% vital pulp were identified as vital in EPT test.
Percussion (tapping on tooth with a metal instrument) and palpation, are to evaluate periodontal inflammation. Necrotic or irreversibly inflamed pulp can lead to inflammation of the periodontal ligament. Inflammation of a tooth with referred pain remains confined within the pulp. The inflammatory process has not yet extended into the periapical region to engage the tactile fibers to give the clinical percussion sign. Sites of referred pain are always the posterior teeth and always unilateral, involving only one tooth in either maxilla or mandible.
In some situations, even the most experienced dentist may not be able to detect the culprit tooth or arriving to a diagnosis. The rule of thumb is to adapt the "wait and see" policy and in most cases, signs and symptoms will be more clearer in the subsequent appointments.
