[Atypical odontalgia - a little known phantom pain]

[Studies on the psychodynamics of Chronic Orofacial Pain Disorder]

Studies on the psychodynamics of Chronic Orofacial Pain Disorder Objectives: Psychodynamic factors play an important role in its emergence and development of Chronic Orofacial Pain Disorder (COP), which is also known as Chronic Primary Orofacial Pain. This factors form the basis for differentiated psychotherapy. Methods: Seven female and two male patients with COP who had visited the Dental School, University Hospital, Ludwig Maximilian University of Munich, and the dental surgery of a practising dentist over the year were included in the study. Following a detailed dental examination, a psychodynamic interview was videotaped, reconstructing the connections between the life history and the development of the illness. Psychosomatic data were assessed by 3 psychotherapists based on a consensus model with regard to symptom trigger mechanisms such as conflicts and pressure, the development of symptoms, and the personality structure. Pathogenetically, we differentiated among conversion, somatization and projection. Results: The patients had a mean age of 57 years (range: 44-67) and an average illness duration of three (1-5) years. The average age where the illness had manifested was 54 (43-64). All patients showed clear psychodynamic factors in the development and course of the illness. The symptoms developed mainly during transitional situations during the life history, predominately in midlife. During this phase, dental treatment undertaken for whatever reason could trigger the chronic symptoms, which could then be further exacerbated by further dental interventions. The mode of symptom development by equal number of patients related to a somatoform disorder, such as a somatization of affect, a conversion with conflict symbolism and a projective-hypochondriac disorder. In the remaining patients, COP was an accompanying symptom of depressive disorder or the consequence of a posttraumatic stress disorder with self-mutilating tendencies. Conclusion: The consideration of psychosomatic connections and pathogenetic differentiation is helpful for the understanding and management of COP. This diagnostic differentiation could serve as a basis for prognosis and for specific therapeutic indications. Despite numerous general researches about chronic pain syndromes, there is a lack of intervention studies which take into account the specific conditions of COP on a larger sample.

Neuropathic orofacial pain: Facts and fiction

Definition and taxonomy This review deals with neuropathic pain of traumatic origin affecting the trigeminal nerve, i.e. painful post-traumatic trigeminal neuropathy (PTTN). Symptomatology The clinical characteristics of PTTN vary considerably, partly due to the type and extent of injury. Symptoms involve combinations of spontaneous and evoked pain and of positive and negative somatosensory signs. These patients are at risk of going through unnecessary dental/surgical procedures in the attempt to eradicate the cause of the pain, due to the fact that most dentists only rarely encounter PTTN. Epidemiology Overall, approximately 3% of patients with trigeminal nerve injuries develop PTTN. Patients are most often female above the age of 45 years, and both physical and psychological comorbidities are common. Pathophysiology PTTN shares many pathophysiological mechanisms with other peripheral neuropathic pain conditions. Diagnostic considerations PTTN may be confused with one of the regional neuralgias or other orofacial pain conditions. For intraoral PTTN, early stages are often misdiagnosed as odontogenic pain. Pain management Management of PTTN generally follows recommendations for peripheral neuropathic pain. Expert opinion International consensus on classification and taxonomy is urgently needed in order to advance the field related to this condition.

[Experience in treatment of patients with neuropathic facial pain using ziconotide]

We report on the intrathecal use of ziconotide in three patients with idiopathic facial pain after surgery of the mouth, jaw or face and one patient with neuropathic pain after damage of the lingual nerve. The therapy was successful in three patients but one patient with idiopathic facial pain had pain relief only during the test phase of ziconotide with an external pump and not after implanting the Synchromed® pump. With intrathecal morphine therapy this patient achieved good pain relief. We recommend that patients with neuropathic facial pain should be treated with ziconotide after implementation of guideline-based therapy. In the test phase the ziconotide dose should be increased by 0.6 µg/day per week after an initial dose of 0.6-1.2 µg/day to avoid side-effects.

Differential effect of intravenous S -ketamine and fentanyl on atypical odontalgia and capsaicin-evoked pain

Atypical odontalgia (AO) is an intraoral pain condition of currently unknown mechanisms. In 10 AO patients and 10 matched healthy controls, we examined the effect of intravenous infusion of an N-methyl-D-aspartate (NMDA) receptor antagonist S-ketamine and a mu-opioid agonist fentanyl on spontaneous AO pain and on an acute intraoral nociceptive input evoked by topical application of capsaicin. The drugs were administered in a randomized, placebo-controlled, cross-over manner. Furthermore, measures of intraoral sensitivity to mechanical and thermal quantitative sensory testing (QST) including temporal summation were compared between groups and sides. Both drugs failed to produce an analgesic effect on spontaneous AO pain, but fentanyl effectively reduced capsaicin-evoked pain. AO patients showed increased sensitivity to capsaicin and heat pain, but no significant differences in cold and mechanical sensitivity compared with healthy controls. No side-to-side differences in QST measures were found in AO patients. The present study demonstrates that AO is unlikely to be primarily due to a persistent afferent barrage from the peripheral region. Furthermore, in contrast to studies on various neuropathic pain conditions, fentanyl and S-ketamine in the present doses failed to attenuate AO pain.

Blink reflexes in patients with atypical odontalgia and matched healthy controls

Atypical odontalgia (AO) is an orofacial pain condition which has been suggested to involve neuropathic pain mechanisms. The aim of this study was to use a brain stem reflex to investigate craniofacial nociceptive mechanisms in AO. In 38 AO patients and 27 matched healthy controls, the R2 component of the blink reflex (BR) was elicited using a "nociceptive-specific" electrode and recorded with surface electromyography electrodes on both orbicularis oculi muscles. The BR was tested by stimulation of both sides of the face of the participants before, during, and after an intraoral pain provocation test with capsaicin. The data were analyzed with three- and four-way mixed-model analyses of variance. The root mean square value of the ipsilateral R2 (R2i) was significantly reduced in patients compared with controls (P=0.046). No differences in R2 between stimulation sides were detected in either group (P>0.757). In all participants, R2 responses and the intensity of the pain evoked by the electrical stimulus were decreased during and after application of capsaicin compared with baseline (P<0.001). In patients, R2i onset latencies were significantly prolonged compared with controls (P=0.031). The present data show disturbances in the central processing of craniofacial information and that endogenous pain inhibitory systems in AO patients and healthy controls were activated to a similar degree by an acute intraoral nociceptive input. Additional clinical research with AO patients will be needed to determine to what extent neuropathic pain mechanisms are involved in this pain condition.

Pain management procedures used by dental and maxillofacial surgeons: an investigation with special regard to odontalgia

Background

Little is known about the procedures used by German dental and maxillofacial surgeons treating patients suffering from chronic orofacial pain (COP). This study aimed to evaluate the ambulatory management of COP.

Methods

Using a standardized questionnaire we collected data of dental and maxillofacial surgeons treating patients with COP. Therapists described variables as patients' demographics, chronic pain disorders and their aetiologies, own diagnostic and treatment principles during a period of 3 months.

Results

Although only 13.5% of the 520 addressed therapists returned completely evaluable questionnaires, 985 patients with COP could be identified. An orofacial pain syndrome named atypical odontalgia (17.0 %) was frequent. Although those patients revealed signs of chronification, pain therapists were rarely involved (12.5%). For assessing pain the use of Analogue Scales (7%) or interventional diagnostics (4.6%) was uncommon. Despite the fact that surgical procedures are cofactors of COP therapists preferred further surgery (41.9%) and neglected the prescription of analgesics (15.7%). However, most therapists self-evaluated the efficacy of their pain management as good (69.7 %).

Conclusion

Often ambulatory dental and maxillofacial surgeons do not follow guidelines for COP management despite a high prevalence of severe orofacial pain syndromes.

Chronic idiopathic orofacial pain. A long-term follow-up study

Patients suffering facial pain that does not fit with the traditional diagnostic criteria and which does not respond to dental treatment constitute a clinical problem. These patients lack a proper diagnosis and are frequently exposed to excessive and inadequate invasive treatment. The aim of this investigation was to study the long-term development of pain and the result of treatment in a cohort of patients suffering chronic idiopathic facial pain. The 74 patients referred to the Facial Pain Diagnostic Group at the Karolinska Institute School of Dentistry between 1981 and 1992 were invited to take part in a follow-up study. As 16 subjects were unwilling or unable to take part in the study and 13 had died, the remaining 45 were interviewed either in accordance with a standard protocol or by filling out a questionnaire mailed to them. The interview revealed that 10 were free of orofacial pain, but only 2 were totally free of pain. Over the 9-19 years' follow-up period the relationship between facial pain and pain in the rest of the body had changed substantially. Of 14 patients and more than 100 extractions, permanent pain relief was felt by only 3 patients. It is concluded that a diagnosis was given in only 2 cases. The distribution of the pain has changed dramatically. The low success rate of invasive treatments suggests that such therapeutic methods are to be considered contraindicated in patients suffering from idiopathic orofacial pain.