An interesting article appears in J Can Dent Assoc 2012;78:c83 titled “Neuropathic Orofacial Pain Patients in Need of Dental Care,” written by Gary D. Klasser and Henry A. Gremillion. It was posted online on August 17, 2012, over at http://www.jcda.ca/article/c83. The abstract of the article states
“Dental pain is a common complaint among the general population. Most pain is a result of traumatic injury or bacterial infection in pulpal and periapical tissues, and dental practitioners are successful at diagnosing these conditions and providing prompt relief. However, in some cases, patients continue to complain of persistent pain, which may be categorized as neuropathic. These people may avoid or neglect routine dental treatment or interventions to prevent precipitation, perpetuation or exacerbation of their pain condition, and practitioners may have to modify their procedures when managing the dental needs of this unique population.”
The article mentions that most dental pain is the result of traumatic injury or bacterial infection and classified as nociceptive or inflammatory. A description of the differences between nociceptive and inflammatory pain is provided. The article states that dental practitioners are very succesful at recognizing and treating these types of pain. The article then goes on to say
“However, in some cases, those who have undergone dental treatments that have been considered both clinically and radiographically successful continue to complain of persistent pain. These people may be experiencing neuropathic pain.”
The article then goes on to state that neuropathic pain may have not have a demonstrable lesion or disease and then becomes classified as dysfunctional pain. The differences of neuropathic pain compared to the two other types of pain are then described.
Neuropathic pain can sometimes lead to what is known as a phantom toothache where a patient complains of pain which they may believe be in a tooth yet the dental practitioner can’t find a clear source of this pain.
The authors then go on to describe the pathophysiology of neuropathic pain and state that complex peripheral and central mechanisms are involved which are not yet fully understood. The authors state that the initiating event is often uknown
“… although it is probable that some form of mechanical trauma, metabolic disorder, neurotoxic chemicals, infection (bacterial, viral, fungal) or tumour invasion causes a release of neurochemicals and inflammatory mediators from the peripheral tissues, primary afferent nerve endings or both. This can increase membrane excitability and decrease the activation threshold of peripheral nociceptors (a process referred to as peripheral sensitization) increasing nociceptive input into the central nervous system (CNS). This bombardment of the CNS induces synaptic plasticity characterized by spontaneous activity, expansion of receptive fields, lowering of activation thresholds, hyperexcitability of neurons in the CNS, anatomic alterations to inhibitory neurons and other neural tissues and genetic alterations (a process referred to as central sensitization).”
The article goes on to describe how when people with neuropathic orofacial pain see a dentist the treatment performed may exacerbate the pain due to a hyperexcitable trigeminal nociceptive system. This can lead to further dental treatments which may or may not be successful. The authors state that dentists should take a comprehensive history and clinical and imaging examinations in order to rule out other potential causes of pain which includes pain from a psychologic origin.
The authors go on to state that local anesthesia should be carefully considered in patients with neuropathic orofacial pain. This is certainly an interesting article and as the authors state in the conclusion all dentists should be aware of neuropathic orofacial pain and able to recognize it. The authors argue that these patients require a team based approach with open communication between all parties.