Journal of Oral & Facial Pain and Headache, 01/2014

Aims: The original Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I diagnostic algorithms have been demonstrated to be reliable. However, the Validation Project determined that the RDC/TMD Axis I validity was below the target sensitivity of ≥ 0.70 and specificity of ≥ 0.95. Consequently, these empirical results supported the development of revised RDC/TMD Axis I diagnostic algorithms that were subsequently demonstrated to be valid for the most common pain-related TMD and for one temporomandibular joint (TMJ) intra-articular disorder. The original RDC/TMD Axis II instruments were shown to be both reliable and valid. Working from these findings and revisions, two international consensus workshops were convened, from which recommendations were obtained for the finalization of new Axis I diagnostic algorithms and new Axis II instruments. Methods: Through a series of workshops and symposia, a panel of clinical and basic science pain experts modified the revised RDC/TMD Axis I algorithms by using comprehensive searches of published TMD diagnostic literature followed by review and consensus via a formal structured process. The panel's recommendations for further revision of the Axis I diagnostic algorithms were assessed for validity by using the Validation Project's data set, and for reliability by using newly collected data from the ongoing TMJ Impact Project-the follow-up study to the Validation Project. New Axis II instruments were identified through a comprehensive search of the literature providing valid instruments that, relative to the RDC/TMD, are shorter in length, are available in the public domain, and currently are being used in medical settings. Results: The newly recommended Diagnostic Criteria for TMD (DC/TMD) Axis I protocol includes both a valid screener for detecting any pain-related TMD as well as valid diagnostic criteria for differentiating the most common pain-related TMD (sensitivity ≥ 0.86, specificity ≥ 0.98) and for one intra-articular disorder (sensitivity of 0.80 and specificity of 0.97). Diagnostic criteria for other common intra-articular disorders lack adequate validity for clinical diagnoses but can be used for screening purposes. Inter-examiner reliability for the clinical assessment associated with the validated DC/TMD criteria for pain-related TMD is excellent (kappa ≥ 0.85). Finally, a comprehensive classification system that includes both the common and less common TMD is also presented. The Axis II protocol retains selected original RDC/TMD screening instruments augmented with new instruments to assess jaw function as well as behavioral and additional psychosocial factors. The Axis II protocol is divided into screening and comprehensive selfreport instrument sets. The screening instruments' 41 questions assess pain intensity, pain-related disability, psychological distress, jaw functional limitations, and parafunctional behaviors, and a pain drawing is used to assess locations of pain. The comprehensive instruments, composed of 81 questions, assess in further detail jaw functional limitations and psychological distress as well as additional constructs of anxiety and presence of comorbid pain conditions. Conclusion: The recommended evidence-based new DC/TMD protocol is appropriate for use in both clinical and research settings. More comprehensive instruments augment short and simple screening instruments for Axis I and Axis II. These validated instruments allow for identification of patients with a range of simple to complex TMD presentations. Keywords: diagnostic criteria, diagnostic reliability, diagnostic validity, sensitivity, specificity, temporomandibular disorders

Aims: To conduct a systematic review to evaluate the evidence of possible benefits of tailored treatments for temporomandibular disorders (TMD) based on randomized controlled trials (RCTs). Methods: Reports of RCTs investigating treatments tailored to TMD patients' psychosocial characteristics were systematically searched for through March 2013 in the following databases: Cochrane Central Register of Controlled Trials, PubMed, and Web of Science. The methodological quality of the RCTs was assessed using the Cochrane Collaboration's tool for assessing risk of bias. Results: Seven reports met the inclusion criteria. In all studies a subgroup of TMD patients, mainly identified by multidimensional diagnostic systems such as the Research Diagnostic Criteria for TMD Axis II or Multidimensional Pain Inventory, were offered a treatment intervention hypothesized to be suitable for that particular patient group. The quality of the trials was compromised in all cases. Two studies focused on well-functioning TMD patients. In both studies, self-care gave results equal to or better than usual conservative TMD treatment. The treatments were targeted for patients with compromised psychosocial adaptation in five studies, and typically included a cognitive behavioral treatment component. In all trials the results supported the efficacy of tailored treatment, albeit in one trial only in the short-term. Conclusion: The identified studies offer cautious support to the notion that treatment targeted to different psychosocial subgroups of TMD pain patients may be beneficial. Keywords: psychosocial, RDC/TMD Axis II, systematic reviews, temporomandibular disorders, treatment tailoring

Aims: To test the role of fatigue and its subtypes (general, physical, emotional, mental, and vigor) in mediating the relationship between psychological distress and pain interference. Methods: Retrospective, de-identified records were examined for 431 patients seeking treatment for persistent orofacial pain. Primary diagnoses of participants were muscle pain (29.8%), joint pain (26.0%), neuropathic pain (19.5%), and other (ie, fibromyalgia, centrally mediated myalgia, tendonitis, dental pain, cervical spine displacement, and no diagnosis; 24.7%). Mediation models were tested with distress as the independent variable, interference as the dependent variable, and fatigue or its subtypes as the mediators. Results: After controlling for pain duration and average levels of pain, total fatigue mediated the relationship between distress and interference. Fatigue subtypes partially mediated the relationship between distress and interference, but mediation was strongest with the composite fatigue variable. The results, however, should be interpreted cautiously, as data were collected at a single time point and do not imply causality. Conclusion: These results suggest that interventions targeted specifically at fatigue symptoms may be helpful for reducing interference and improving quality of life in patients with persistent orofacial pain. Keywords: fatigue, orofacial pain, pain interference, psychological distress

Aims: To conduct a pilot retrospective study to investigate the frequency of pain among patients with early-stage oral squamous cell carcinoma (OSCC) of the tongue and to correlate the pain with clinical and histopathologic parameters. Methods: Twenty-four archival cases of T1 OSCC of the tongue were reviewed. No power analysis was conducted due to the pilot nature of the study. Tumors were classified into two groups according to the presence or not of pain (P+ and P- groups). Clinical and histopathologic parameters, such as grade of differentiation, depth of invasion, and presence of vascular, muscular, and perineural invasion were recorded. Statistical analyses included parametric (Student t) and nonparametric (chi-square) tests. Results: Pain was reported by 13 of the 24 patients. In the P+ group, 11 of the 13 had moderately differentiated and 2 well-differentiated tumors; in contrast, P- patients had moderately differentiated tumors in 5 of the cases and well-differentiated tumors in 6 cases (P = .082). Vascular invasion was observed in 5 of the 13 P+ and 5 of the 11 P- patients, muscular invasion in 5 P+ and 2 P- patients, and perineural invasion in 4 P+ and 1 P- patients, respectively. The mean depth of invasion was 1.51 mm for P+ patients and 1.25 mm for P- patients. Only lymphoplasmocytic infiltration differed significantly, with P+ tumors exhibiting more intense inflammation (P = .041). Conclusion: Despite the limited number of cases, the results of this study suggest that painful OSCCs of the tongue may be associated with more intense inflammation. Keywords: histologic grade, pain in cancer, perineural invasion, squamous cell carcinoma, tongue

Aims: To evaluate pharmacotherapeutic success in patients with painful traumatic trigeminal neuropathy (PTTN) and to identify patient or pain characteristics that may predict treatment outcome. Methods: Pharmacotherapy was instituted for PTTN patients and was based on widely accepted protocols for neuropathic pain and conducted in an open fashion. Outcome was assessed by employing prospective diaries recording pain intensity measured with an 11-point (0 to 10) verbal pain score (VPS). Individual characteristics in the patients and their influence on outcome were analyzed. Treatment results in the PTTN patients were compared with those in classical trigeminal neuralgia (CTN) patients, who were used as a comparative cohort. Data were analyzed with a Pearson chi-square test for nominal variables and with an independent samples t test or analysis of variance for continuous variables. Results: A total of 145 patients were included: 91 with PTTN and 54 with CTN. In PTTN patients, 11% had a ≥ 50% reduction in pain intensity. Higher VPS scores in the PTTN patients were associated with a significantly reduced response to therapy (P = .03). No other pain-related or demographic parameters were associated with treatment outcome in the PTTN patients. Also the response rate of PTTN patients was significantly inferior to that of CTN patients, 74.1% of whom attained a significant reduction in pain intensity (P .001). Conclusion: This study underpins the poor pharmacotherapeutic prognosis of PTTN. The results support findings on neuropathic pain in other sites and point to the need for further research and reexamination of current PTTN treatment protocols. Keywords: antidepressants, antiepileptic drugs, orofacial pain, trigeminal neuralgia

Aims: To clarify the antiallodynic effects of the α2-adrenergic receptor antagonist mirtazapine compared with those of gabapentin and pregabalin in a rat model of orofacial neuropathic pain. Methods: Mirtazapine (10, 30, and 100 μg), gabapentin (10, 30, and 100 μg), and pregabalin (3, 10, and 30 μg) were administered intrathecally to eight male Sprague-Dawley rats with orofacial neuropathic pain induced by chronic constriction injury of the infraorbital nerve that had been carried out 2 weeks previously. Stimulation using von Frey filaments (1.0 to 15.0 g) applied to skin innervated by the injured infraorbital nerve enabled the measurement of mechanical thresholds 0 to 180 minutes after drug injection. Time-course data for the dose-response effects were analyzed using two-way analysis of variance and the posthoc Tukey-Kramer multiple-comparison test. Results: Intrathecal administration of not only gabapentin and pregabalin but also mirtazapine reversed the lowered mechanical nociceptive thresholds produced by the nerve injury. The ED50 (95% confidence interval) was (in μg) 49.00 (39.71-58.29) for mirtazapine, 54.84 (46.12-63.56) for gabapentin, and 13.47 (11.24-15.69) for pregabalin. Conclusion: Intraspinal administration of either mirtazapine, gabapentin, or pregabalin reverses the lowered facial mechanical thresholds produced in a rat model of trigeminal neuropathic pain. Keywords: allodynia, gabapentin, mirtazapine, orofacial pain, pregabalin

Aims: To investigate the changes in condylar cartilage and subchondral bone of the temporomandibular joint (TMJ) in a mouse model of incisor malocclusion. Methods: By bonding a single (single group) or a pair (pair group) of metal tube(s) to the left incisor(s), a crossbite-like relationship was created between left-side incisors in mice. The morphological changes in the TMJ condyles were examined by hematoxylin and eosin and toluidine blue staining. Indices of osteoclastic activity, including tartrate-resistant acid phosphatase (TRAP) staining and macrophagecolony stimulating factor (M-CSF) were investigated by histochemistry or real-time polymerase chain reaction (PCR). The osteoblastic activity was indexed by osteocalcin expression. Expressions of semaphorin 4D and its receptor, Plexin-B1, were detected by real-time PCR. Two-way analysis of variance was used to assess the differences between groups. Results: One week and 3 weeks after bonding the metal tube(s), cartilage degradation and subchondral bone loss were evident histologically. Both indices of osteoclastic activity (TRAP and M-CSF) were significantly increased in cartilage and subchondral bone after bonding the metal tube(s). Osteocalcin expression in cartilage was significantly increased at week 3, while its expression in subchondral bone was significantly increased at week 1 but decreased at week 3. The semaphorin 4D expression in cartilage and subchondral bone was significantly decreased at week 1 but significantly increased at week 3. For Plexin-B1 expression, a significant increase was detected in subchondral bone at week 3. Conclusion: Bonding a single or a pair of metal tube(s) to left incisor(s) is capable of inducing remodeling in the TMJ, which involved cartilage degradation and alteration of osteoclastic and osteoblastic activity. Keywords: cartilage, occlusion, remodeling, semaphorin 4D, temporomandibular joint

Numb chin syndrome (NCS) describes a sensory neuropathy characterized by numbness in the distribution of the terminal branch of the mandibular division of the trigeminal nerve. Benign as well as malignant diseases are known to cause NCS. This is often misdiagnosed, and in some cases the symptom may lead to a late detection of malignancy. Reports of 10 cases in which NCS was the presenting and isolated symptom, caused by extracranial malignancies, drugs, or dental/surgical interventions, are presented. This article outlines the symptoms and the diagnostic approaches taken, provides a short review of the etiology and pathogenesis, and proposes diagnostic criteria and treatment of NCS. Both medical practitioners and dentists need to be aware of the relationship between malignancies and paresthesia of the chin or complete loss of sensation in partial segments of the jaw. In addition, dentists should be aware of the diagnostic limitations of an orthopantomogram to detect underlying diseases beyond localized dental disorders. Keywords: bisphosphonate-related osteonecrosis of the jaw (BRONJ), dental implant, iatrogenic, metastasis, multiple sclerosis, neuropathy, numb chin syndrome