Subject areas include masticatory and cervical musculoskeletal pain, neurovascular pain, neuropathic pain, sleep disorders, orofacial dystonias, and intracranial, extracranial, and systemic disorders that cause orofacial pain. Dentists trained as pain management practitioners use clinical skills in dentistry, psychology, neurology, anesthesiology, rheumatology, physical therapy, otolaryngology, and rehabilitation medicine to help diagnose, refer for evaluation, and treat these disorders.
The orofacial pain (center) bridges the gap between traditional dental and medical practices, allowing the possibility that pain such as migraines or trigeminal neuralgia may have a complex dental etiology.
A growing body of evidence in neuroscience, muscle physiology, and cardiovascular literature is prompting those in the medical field to redefine chronic pain disorders such as TMD. New concepts are expanding the way doctors view orofacial pain, a condition that is not now accepted as a purely dental dilemma, but in the broader context of a psychoneuroimmunological problem.* Portions of this material provided courtesy of the National Naval Medical Center in Bethesda, MD; www.news.navy.mil
Story Number: NNS020307-05.
However, several conditions (marked by an *) are worthy of further comment for the pain management clinician as they can be of an acute but recurrent nature and thus may be referred to a pain management clinic. A brief summary of the common acute dental pain states is given.
Acute Dental Pain: Inflammation of the pulp of a tooth, due to caries, a leaking filling or restoration, or a cracked tooth.
Dental disease of the hard tissues (caries of enamel, dentine and cementum) and soft tissues and supporting bone (gingivitis / periodontitis) are the recognised as the most common diseases to afflict the general population. These conditions are largely diagnosed and treated by dental practitioners by history, dental clinical examination and radiographs. However, several conditions are worthy of further comment for the pain management clinician as they can be of an acute but recurrent nature and thus may be referred to a pain management clinic. A brief summary of the common acute dental pain states is given.
Dental pulpitis (“toothache”). Typically characterised by an aching or throbbing pain often as a result of dental caries or a leaking dental restoration. It is worse following food or fluid intake. The pain may be sharp, following pressure applied to tooth cusps where the causal factor is a crack in the tooth. Where there is a lack of radiographic evidence of pathology, referred pain from muscles into teeth should always be considered before root canal therapy.
Premature contact (or ‘high bite’). Characterised by a sharp (then dull after a period) pain due to a recent tooth restoration that is ‘high’ compared with the normal occlusion when biting together.
Exposed cementum or dentine. The tooth root surface (a thin layer of cementum overlaying dentine) is exposed from excessive/incorrect toothbrushing. There is tooth sensitivity from cold fluids/air.
Alveolar osteitis (“dry socket”). It occurs several days after a tooth extraction when the blood clot in the socket is lost through mechanical means (excessive and vigorous rinsing) or salivary based enzymic (fibrinolytic) factors. Patients complain of a deep ache in the extraction socket.
*Post-surgical pain. Severe aching pain can follow surgical extraction or endodontic treatment (root canal therapy or apicectomy). While the majority of patients improve over time (in weeks), a few (2-3%) will develop a chronic (neuropathic) pain state as a result of treatment. This is not the fault of the treating doctor, and should be referred to an orofacial pain management doctor.
*Maxillary sinusitis. Recurrent maxillary sinusitis may cause widespread pain in the maxillary teeth. The pain has a continuous aching quality and is usually made worse by bending forward. It can mimic TMD or neuropathic pain, and improves with medications used to treat chronic sinusitis such as antibiotics.
*Trigeminal neuraligia (TN). TN is characterized by intermittent, shooting pain in the face. Unfortunately, TN is diagnosed by clinical symptoms and not cause. The initial treatment for trigeminal neuralgia should be medical. All patients should have an MRI scan of the head to evaluate for any intracranial abnormality. One cause of Trigeminal Neuralgia is an enlarged looping artery or vein pressing on the trigeminal nerve at the base of the brain. Other less frequent causes are multiple sclerosis or a brain tumor, both of which can usually be identified by MRI scan when they exist. Frequently, trigeminal neuralgia is misdiagnosed and can be the result of an undiagnosed dental problem. An orofacial pain practitioner should always be consulted prior to invasive procedures such as brain surgery or medications such as carbamazepine (Tegretol®), gabapentin (Neurontin®), Baclofen, clonaxepan, and valproic acid.
*Migraine Headaches. Approximately 50% of all migraine headaches have a dental etiology. Migraine medications such as Imitrex may only treat the symptoms. When MRIs are negative, multiple migraine medications fail, and the recurrence of these headaches is refractory to treatment, the orofacial pain specialist should be consulted as these migraines are most likely dental in origin.
*Burning Mouth Syndrome. Burning mouth syndrome (BMS) is defined by the International Association for the Study of Pain as a burning pain in the tongue or other oral mucous membranes associated with normal signs and laboratory findings. The condition is now thought to be an intraoral form of neuropathic pain.
There is predilection for the condition for females in the menopausal to post-menopausal age group. The prevalence varies from 0.5-15% in this targeted group. Afflicted patients report a constant burning sensation. The preferred site for the pain is the anterior portion of the tongue although the anterior portion of the hard palate and the labial mucosa of the lip region are other common sites of pain.
Some causes of burning mouth syndrome follow:Treaments for burning mouth syndrome include:
There are no simple treatments that have proven to be effective in the majority of patients.
Oral Neuropathic pain. This pain is characterized as a persistent and severe pain, often with sensory pain qualities that are described as burning, sharp, and stabbing. Associated features include hyperalgesia, allodynia, sympathetic hyperfunction and secondary myofascial pain. There is often a delay in the onset of the pain after the initial injury (days - months) and there is a lack of identifiable clinical or radiographic abnormalities. The prevalence of neuropathic pain as a result of maxillofacial trauma and surgery has not been established but its incidence following other types of surgery is high; between 2-97% of patients with phantom limb pain and 26-65% of postmastectomy patients.
The treatment/management of neuropathic pain is multidisciplinary and includes a psychological assessment that is often crucial in developing strategies for pain management. Psychological variables include distress, depression, expectations of treatment, motivation to improve, and background environmental factors. Drug regimens utilise tricyclic antidepressants, anticonvulsants, and topical applications of capsaicin for intraoral pain.
Unfortunately, surgical revision for neuropathic pain is usually contraindicated as there is a high risk of propagating further maladaptive changes in the sensory pathways of the peripheral and central nervous systems. Furthermore, expectations of surgery to ‘fix’ pain when there is significant background psychological distress often lead to poor patient outcomes (Turk et al., 1983). Accurate and comprehensible information provided by the surgeon to the patient at the preoperative stage may change the way the patient construes his/her pain and can reduce the risk of the patient developing postoperative chronic pain (Gamsa, 1994). Absence of information, on the other hand, may promote anxiety and fear, in the presence of pain, (Vlaeyen and Linton, 2000), and lead to avoidance of normal daily activities (Linton, 1985). Failure to attend to the patient’s fear of pain may interfere with patient trust of the surgeon and, by an operant conditioning process, make more likely the rejection of any future surgeon’s advice (Turk and Rudy, 1991; Turk and Flor, 1999). Thus, there are a number of important potential risks for the surgeon who does not integrate physiological and psychological factors in preoperative, perioperative and postoperative care.
* Other portions of text: Russell Vickers, PhD -- http://www.painmgmt.usyd.edu.au