Journal of Oral & Facial Pain and Headache, 02/2017

Aims: To assess the effects of experimental muscle pain and topical lidocaine applied to the skin overlying the masseter muscle on the mechanical somatosensory profile and face perception of the masseter muscle in healthy participants. Methods: A total of 28 healthy participants received a 45-minute application of a lidocaine or placebo patch to the skin overlying the masseter muscle followed by one injection of 0.2 mL sterile solution of monosodium glutamate. Measurements were taken four times during each session of quantitative sensory testing (QST) (T0 = baseline, T1 = 45 minutes after patch application, T2 = immediately after glutamate injection, and T3 = 25 minutes after the glutamate injection), and the following variables were measured: mechanical detection threshold (MDT), mechanical pain threshold (MPT), pressure pain threshold (PPT), pain report (pain on palpation, pain spreading on palpation, and pain intensity), pain drawing, and perceptual distortion. Multi-way within-subjects analysis of variance (ANOVA) was applied to the data. Results: The highest MDTs were present at T2 (F = 49.28, P .001), the lowest PPTs were present at T2 and T3 (F = 21.78, P .001), and the largest magnitude and area of perceptual distortion were reported at T2 (F > 6.48, P .001). Conclusion: Short-lasting experimental muscle pain was capable of causing loss of tactile sensitivity as well as perceptual distortion of the face, regardless of preconditioning with a topical lidocaine patch. Short-term application of a lidocaine patch did not significantly affect the mechanical somatosensory profile. Keywords: local anesthesia, musculoskeletal pain, pain measurement, sensory thresholds, touch perception

Aims: To compare the anesthetic efficacy of 1.8 mL of 2% lidocaine with 1:200,000 epinephrine, 4% articaine with 1:100,000 epinephrine, and 0.5% bupivacaine with 1:200,000 epinephrine on producing inferior alveolar nerve block (IANB) in patients with symptomatic irreversible pulpitis. Methods: A total of 91 adult patients who were actively experiencing mandibular molar pain were involved in this study. The patients were randomly divided into three groups on the basis of the anesthetic solution used. The first group received IANB with 1.8 mL of 2% lidocaine with 1:200,000 epinephrine, the second group received IANB with 4% articaine with 1:100,000 epinephrine, and the third group received IANB with 0.5% bupivacaine with 1:200,000 epinephrine. After 15 minutes of IANB, conventional endodontic access preparation was started. The pain during the treatment was noted on a Heft-Parker visual analog scale (HP VAS). The primary outcome measure was anesthetic success, and anesthesia was considered successful if the patient reported no pain or weak/mild pain (HP VAS score 55 mm) during endodontic treatment (pulp access and canal preparation procedures). The data were analyzed with one-way analysis of variance and chisquare test. Results: The anesthetic success rates of 2% lidocaine, 4% articaine, and 0.5% bupivacaine were 23%, 33%, and 17%, respectively. The differences were statistically insignificant (P > .05). Conclusion: The 2% lidocaine solution used for IANB had similar success rates when compared with 4% articaine and 0.5% bupivacaine. Keywords: anesthetic success, inferior alveolar nerve block, irreversible pulpitis, local anesthetic solutions

Aims: To conduct a functional examination using multimodal exploration of a sample of patients with iatrogenic trigeminal nerve injury to understand the underlying mechanisms of neuropathic pain following trigeminal nerve injury. Methods: Subjective and objective symptoms and responses to thermal and electrical quantitative sensory testing (QST) were evaluated in 85 patients with unilateral trigeminal nerve injury. Objective symptoms were measured by seven clinical sensory tests. Thermal QST included cold detection threshold (CDT), warm detection threshold (WDT), and heat pain threshold (HPT). Electrical current perception threshold was performed with electrical stimuli of 2,000, 250, and 5 Hz. The time since injury was included as a possible independent variable. The data were analyzed using chi-square test, independent t test, Mann Whitney U test, one-way analysis of variance (ANOVA), and Kruskal-Wallis test. Further analyses with Pearson correlation analysis, Spearman rank correlation analysis, and cluster analysis were applied. Results: Unlike objective symptoms, thermal and electrical QST values and subjective symptoms did not improve in patients with an old injury. Thermal QST, particularly WDT, showed the highest positive correlation with subjective symptoms in all tests. Cluster analysis of the thermal QST values identified three subgroups: cluster 1, which was characterized by prominent cold and warm hypoesthesia; cluster 2, which presented elevated WDT; and cluster 3, which showed the smallest thermal differences for all thermal variables but had the highest proportion of neuropathic pain. Conclusion: These findings have demonstrated that thermal QST is a suitable tool for evaluating and characterizing the sensory effects of trigeminal nerve injury. Three subgroups with different thermosensory profiles showed that the less the damage, the more neuropathic pain occurs. The loss of warm perception in particular might play a pivotal role in the chronicity and severity of subjective sensory symptoms. Keywords: prognosis, thermal, trigeminal nerve injury, quantitative sensory testing, warm

Aims: To assess the effect of topical application of capsaicin to the tongue as a surrogate model of burning mouth syndrome (BMS) on somatosensory sensitivity by using a standardized battery of quantitative sensory testing (QST) in healthy volunteers. Methods: This study comprised two experimental sessions (experimental [capsaicin] and control [Vaseline]) with QST in 16 healthy women. The examiner applied capsaicin or Vaseline to the tongue tip for 5 minutes. Each participant kept their tongue tip in contact with the capsaicin/ Vaseline at the bottom of a disposable cup for 5 minutes, during which time the participant rated the perceived intensity of the tongue pain every 30 seconds on an electronic 0 to 10 visual analog scale (VAS). QST was performed on the tongue tip before and immediately after application in each session. The QST data were analyzed by two-way analysis of variance (ANOVA). Results: Mean ± standard error of the mean (SEM) of VAS pain scores during the capsaicin and control sessions were 8.2 ± 0.5 and 1.9 ± 0.2, respectively. The peak of the perceived pain in the capsaicin session was significantly higher than in the control session (P .001). In the capsaicin session, the postapplication heat pain threshold (HPT) was significantly higher than the preapplication HPT, and the postapplication cold detection threshold (CDT) and mechanical pain threshold (MPT) were significantly lower than before application (P .001). The average z scores showed a significant somatosensory loss regarding CDT. In the control session, there were no differences between preapplication and postapplication values. Conclusion: Topical application of capsaicin to the tongue tip changed somatosensory sensitivity in healthy participants. Keywords: burning mouth syndrome, capsaicin, orofacial pain, quantitative sensory testing, tongue

Aims: To evaluate the quality and readability of online information about the treatment of burning mouth syndrome (BMS). Methods: An internet search using the phrase "burning mouth syndrome treatment" was carried out on the Google search engine (www.google.co.uk) on 8 June 2015, and the first 100 websites listed were examined. Data collection included DISCERN score, the Journal of the American Medical Association (JAMA) benchmarks for website analysis score, the presence of the Health on the Net (HON) Foundation seal, and the Flesch Reading Ease Score (FRES). Descriptive statistics were performed using Microsoft Office Excel. Results: The search strategy initially yielded 635,000 links; following the application of the exclusion criteria, 53 sites remained for analysis. The overall DISCERN score varied between websites, with half of all websites achieving an overall score of 2 and none of these websites achieving the maximum score of 5. The mean score ± standard deviation (SD) was 2.4 ± 0.7. Only 10 (18.9%) of the websites achieved the four JAMA benchmarks while 3 (5.7%) of the websites did not achieve any of them. Only 9 (17%) displayed the HON seal. The FRES of the websites ranged from 32.4 to 82.2; the mean ± SD rating was 55.4 ± 10.7, which is considered to reflect fairly difficult reading. Conclusion: The information available online about BMS is of questionable quality and content. Perhaps engaging patients in determining what type and format of information they desire when searching online for health information could guide clinicians and researchers alike in providing reliable and readable information sources. Keywords: burning mouth syndrome, online health information, patient information, quality of life, shared decision-making

Aims: To quantify the practice patterns of Japanese dentists in the management of pain related to temporomandibular disorders (TMD) and to identify specific characteristics that are significantly associated with the decision to perform occlusal adjustment for TMD-related pain. Methods: A cross-sectional study was conducted consisting of a questionnaire survey of dentists affiliated with the Dental Practice-Based Research Network Japan (JDPBRN) (n = 148). Participants were asked how they diagnosed and treated TMD-related pain. Associations between dentist characteristics and the decision to perform occlusal adjustment were analyzed via multiple logistic regression. Results: A total of 113 clinicians responded to the questionnaire (76% response rate), and 81% of them (n = 89) had treated TMD during the previous year. Dentists treated an average of 1.9 ± 1.8 (mean ± SD) patients with TMD-related pain per month. Most JDPBRN dentists used similar diagnostic protocols, including questions and examinations. The most frequent treatments were splints or mouthguards (96.5%), medications (84.7%), and self-care (69.4%). Occlusal adjustment for TMD-related pain was performed by 58% of the participants. Multiple logistic regression analysis identified two factors significantly associated with the decision to perform occlusal adjustment: dentist lack of confidence in curing TMD-related acute pain (odds ratio [OR] 5.60; 95% confidence interval [CI] 1.260 to 24.861) and proportion of patients with severe TMD-related pain (OR 0.95; 95% CI 0.909 to 0.999). Conclusion: The most common treatments for TMD-related pain were reversible treatments; however, over half of the dentists performed occlusal adjustment for TMD-related pain. The results of this study suggest that an evidence-practice gap exists for occlusal adjustment for TMD-related pain. Keywords: evidence-practice gap, practice pattern, practice-based research, temporomandibular disorders

Aims: To investigate the prevalence of temporomandibular disorders (TMD) in the 46-year-old cohort subjects from the Northern Finland Birth Cohort 1966 (NFBC 1966). Methods: Altogether, 1,962 subjects (1,050 women, 912 men) participated in a clinical medical and dental examination and responded to questionnaires in 2012 to 2013. The stomatognathic examination was performed according to a modified protocol of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Pearson's chi-square test and Fisher's exact test were used to analyze the signs of TMD between genders, and logistic regression models were used to analyze the relationship between self-reported pain associated with TMD and modified DC/TMD protocol (P .05). Results: Of the subjects available for analyses, 18.5% responded positively to the self-reported screening question for pain related to TMD. The most common signs of TMD were clicking in the temporomandibular joint (TMJ) (26.2%) and palpation pain in the masticatory muscles (11.2%). Women had signs of TMD more often than men (P .05). The most common diagnosis was disc displacement with reduction (7.0%). Myalgia, arthralgia, disc displacement with reduction, and degenerative joint disease diagnoses were statistically significantly more common in women than in men (P .05). The prevalence of TMD signs among the cohort subjects was 34.2%. Conclusion: The most common sign of TMD was clicking in the TMJ and the most common TMD diagnosis was disc displacement with reduction. The prevalence of TMD signs among the examined cohort subjects was 34.2%. TMD was diagnosed in women more often than in men. The results are comparable with other corresponding population-based studies in adults. Keywords: cohort study, DC/TMD, NFBC 1966, temporomandibular disorders, TMD

Aims: To determine possible predictive factors for long-term temporomandibular joint (TMJ) degeneration and dysfunction in juvenile idiopathic arthritis (JIA) patients. Methods: A total of 94 patients (77% female) who had received a JIA diagnosis in an outpatient rheumatology clinic from 1993 to 1994 at a mean ± standard deviation age of 8.3 ± 4.53 years were included in the study. At inclusion, TMJ status regarding condylar degeneration was assessed orthopantomographically and given a Rohlin and Petersson score of 0 or ≥ 1. The maximal mouth opening (MMO) was also measured. Data on possible predictors were gathered retrospectively from the consultation at intake: gender, age at JIA onset, JIA subtype, physical limitations (ie, a Steinbrocker classification score of 0 or ≥ 1), human leukocyte antigen-B27, and antinuclear and rheumatoid factors. Disease duration and medication type were also considered. Associations between all of these factors and long-term condylar degeneration and MMO were assessed by using single and multiple regression analyses. Results: Long-term TMJ degeneration and smaller MMO were both associated with younger age at JIA onset (P = .01; P = .03) and longer disease duration (P = .05; P = .002). Moreover, MMO was negatively associated with physical limitations at intake (P = .04). Conclusion: Within the limitations of this retrospective study design, these results suggest that young JIA patients with early physical limitations and prolonged disease are at risk of long-term TMJ degeneration and impaired mobility. Keywords: juvenile idiopathic arthritis, long-term, mandibular function, predictive factors, temporomandibular joint

Aims: To develop an equation capable of relating the evolution of oral pain to the time elapsed, measured from the moment of dental archwire fitting and identifying when pain begins, peaks, and ends; and secondly, to compare pain during orthodontic treatment in relation to archwire material (steel or nickeltitanium [Ni-Ti]) and position (maxillary or mandibular) and patient age (child, teenager, or adult) and gender (male or female). Methods: A longitudinal prospective cohort study was conducted of 112 patients who filled in a scale to evaluate pain, noting the times when the pain occurred. The total sample consisted of 60 males and 52 females with a mean (± standard deviation [SD]) age of 19.8 ± 6.2 years. The sample was divided into five groups depending on archwire material and position, and patient age and gender. A univariate four-way ANOVA model was performed to compare mean pain levels between groups. Bonferroni test was used for multiple comparisons. A univariate nonlinear regression model was carried out for pain level, 95% confidence intervals (95% CI) were calculated, and the statistic R2 was used. Results: An equation was developed based on pain levels in relation to time elapsed, measured from the moment when the archwire had been fitted in the mouth. The equation had three coefficients related to mean pain values: overall pain, peak pain, and how pain decreased. It fitted all study groups with a correlation coefficient > 0.9. The model showed that pain levels were influenced by archwire material and patient gender and age, but not archwire position. Conclusion: The equation reproduced the data registered and can be applied to studies of pain derived from archwires, and this methodology could be used for other external agents fitted in the mouth. Patients receiving dental treatment involving external agents can be made aware of the pain they can expect to experience. This will enable them to distinguish expected pain from other pain, which will help them identify other pathologies requiring medical attention and to approach treatment with better motivation since the pattern of pain evolution is known in advance. Keywords: archwire, dental treatment, evolution of pain, mathematical equation, visual analog scale

This article describes the case history of a 59-year-old female patient who sought advice for temporomandibular joint (TMJ) pain and sounds but who was actually diagnosed with a primary lung cancer with metastasis to the TMJ. The patient had a history of TMJ pain and deflection in jaw movement that progressively worsened over a few months and did not improve with the usual standard of care treatment provided by an orofacial pain practitioner. Magnetic resonance and computed tomography (CT) prescribed at a tertiary clinic showed an osteolytic bone mass within the right TMJ condyle. The neoformation was surgically removed and histologic assessment revealed it was a metastasis of a silent lung carcinoma. Thorax CT confirmed the presence of a formation within the apical segment of the right lung superior lobe. While this scenario of a silent lung cancer metastasis to the TMJ condyle mimicking classical symptoms of temporomandibular disorders (TMD) is rare, it does indicate that the path to differential diagnosis is often difficult in TMD and orofacial pain patients, and that practitioners managing such patients should be aware of the variegate spectrum of possible TMD-mimicking conditions to avoid dangerous diagnostic delays. Keywords: cancer, lung, neoplasm, temporomandibular disorders, temporomandibular joint