The best known of the cranial neuralgias is trigeminal neuralgia (TGN) which is defined as: “A sudden, usually unilateral, severe, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve“.
Pain intensity ratings vary from “mild” to “excruciating” or “intolerable”. Uncontrolled pain has been associated with suicide. While commonly presenting as ‘electric shocks’ or ‘spasms’ of pain, this condition may manifest as a dull aching discomfort (referred to as pre-trigeminal neuralgia). Most commonly, TGN affects the second (maxillary) and third (mandibular) divisions of the trigeminal nerve, either individually or in combination. Understandably, this type of pain located in the tooth-bearing regions of the mandible and maxilla, may be misdiagnosed as odontogenic (i.e., pain from dental or periodontal disease). The vast majority of reported TGN cases are unilateral in location, but bilateral pain has been reported.
Affected patients are usually in their fifth or sixth decade of life, but exceptions do occur. Distribution between male and female patients is approximately equal. Onset may be abrupt with rapid onset of extremely severe pain, or it may have an insidious nature with slow progression of symptoms. Periods of remission are characteristic of the condition and further complicate the diagnosis. Susceptible patients may attribute the sudden onset of pain to recent dental interventions or facial injury. However, the aetiology of this distressing condition is uncertain, and current opinion focuses on compression of the trigeminal nerve root by a tortuous blood vessel. Space-occupying lesions within the posterior cranial fossa may produce similar symptoms, but obviously the approach to treatment of this secondary or symptomatic type of TGN is quite different.
Attacks of pain may be triggered by relatively innocuous activities such as shaving, washing the face, tooth brushing, etc. This potential to trigger pain by gentle movement of skin, tooth, or lateral border of the tongue is unique to TGN. These areas of acute sensitivity are referred to as trigger zones, which by definition ignite an attack of sharp, electrical pain on stimulation. Over time these trigger zones may change in location or disappear completely, leaving the patient with spontaneous episodes of pain, until the condition resolves. The region most commonly affected is the infra-orbital area, which includes the incisor, canine and premolar teeth. It is not unusual for a canine or premolar tooth to act as a trigger zone, responsive to mechanical or thermal stimulation. The resultant pain is often excruciating but brief in duration. A latent period (two to four minutes) follows during which the pain cannot be provoked. This period of latency during which the pain cannot be triggered helps to distinguish between pain of pulpal origin and TGN. Local anaesthetic injection either by nerve block or infiltration into the symptomatic region will successfully block the pain. This is somewhat surprising given the likelihood of this condition having a central origin.
The nerves which supply teeth are part of the trigeminal nervous system. However, those nerves which carry headache pain are also part of the trigeminal nervous system. Thus it is not surprising that headache problems can also affect teeth to a major extent. One of the big issues for patients who suffer from chronic orofacial pain is the potential for overuse of simple painkillers like Nurofen, paracetamol and Solpadeine, etc. If the underlying problem is headache related, overuse of these ordinary painkillers (overuse means taking them more than one or two days per week) will ultimately make the problem worse. In other words, headache pains in the face can become more frequent if you take this type of painkiller on a frequent basis.
Apart from migraine, there are other headache disorders which can cause very severe pain in the orofacial region. Some of these disorders are listed below.