Journal of Oral & Facial Pain and Headache, 03/2010

Aims: To conduct a systematic review with meta-analysis of randomized controlled trials (RCTs) that have assessed the efficacy of intraoral orthopedic appliances to reduce pain in patients with temporomandibular disorders affecting muscle and joint (TMJD) compared to subjects receiving placebo control, no treatment, or other treatments. Methods: A search strategy of MEDLINE, the Cochrane Library, the Cochrane CENTRAL Register, and manual search identified all English language publications of RCTs for intraoral appliance treatment of TMJD pain during the years of January 1966 to March 2006. Two additional studies from 2006 were added during the review process. Selection criteria included RCTs assessing the efficacy of hard and soft stabilization appliances, anterior positioning appliances, anterior bite appliances, and other appliance types for TMJD pain. Pain relief outcome measures were used in the meta-analyses, and the QUORUM criteria for data abstraction were used. A quality analysis of the methods of each RCT was conducted using the CONSORT criteria. The review findings were expressed both as a qualitative review and, where possible, as a mathematical synthesis using meta-analysis of results. Results: A total of 47 publications citing 44 RCTs with 2,218 subjects were included. Ten RCTs were included in two meta-analyses. In the first meta-analysis of seven studies with 385 patients, a hard stabilization appliance was found to improve TMJD pain compared to non-occluding appliance. The overall odds ratio (OR) of 2.46 was statistically significant (P = .001), with a 95% confidence interval of 1.56 to 3.67. In the second meta-analysis of three studies including 216 patients, a hard stabilization appliance was found to improve TMJD pain compared to no-treatment controls. The overall OR of 2.15 was positive but not statistically significant, with a 95% confidence interval of 0.80 to 5.75. The quality (0 to 1) of the studies was moderate, with a mean of 55% of quality criteria being met, suggesting some susceptibility to systematic bias may have existed. Conclusion: Hard stabilization appliances, when adjusted properly, have good evidence of modest efficacy in the treatment of TMJD pain compared to non-occluding appliances and no treatment. Other types of appliances, including soft stabilization appliances, anterior positioning appliances, and anterior bite appliances, have some RCT evidence of efficacy in reducing TMJD pain. However, the potential for adverse events with these appliances is higher and suggests the need for close monitoring in their use. Keywords: intraoral orthopedic appliances, systematic review, temporomandibular disorders

Aims: To compare the modulatory effects of tonic mechanical or thermal craniofacial painful conditioning stimuli on pain sensitivity in craniofacial and spinal test sites in healthy men and women. Methods: Mechanical and cold headbands were developed and tested on 12 healthy men and 12 age-matched women (mean ± SEM: 27 ± 1.5 years). The pressure applied by the mechanical headband around the skull above the eyebrows could be adjusted over time via feedback from a 0 to 10 electronic visual analog scale (VAS) to maintain the pain intensity at a given level for 10 minutes (3 to 7 on VAS). The cold headband consisted of a series of plastic bags filled with antifreeze water having a temperature of approx 3°C. During the 10 minutes of application, the subjects were asked to rate the pain intensity on a 10-cm VAS. Pressure pain thresholds (PPT) were recorded over the right and left masseter muscles (MAR, MAL), right splenius muscle (neck), right elbow (elbow), and right middle finger (finger) by a pressure algometer (1-cm2 area probe). The PPTs at each of the five sites were determined at baseline and during the mechanical or cold-induced pain. The two sessions with mechanical or cold headbands were performed at an interval of 30 minutes. Results: Women had significantly lower absolute PPT values than men at most test sites (Unpaired t-test: P .027). The mechanical headband caused pain in both men (peak pain mean ± SEM: 4.7 ± 0.4 cm) and women (4.9 ± 0.4 cm) (P = .455). A significant PPT elevation was found at MAR, MAL, neck, and finger in men (11% to 17%; P .031) and at MAR, MAL, and neck in women (15% to 22%; P .020) during the mechanical-induced pain. The cold headband caused pain in both men (4.0 ± 0.4 cm) and women (4.5 ± 0.4 cm) (P = .285). During the cold-induced pain, a significant PPT elevation was found at all test sites in men (P .023) and at all sites (P .021) except for the finger in women. The relative changes in PPT values were not significantly different between men and women at any test site (unpaired t-test: P > .446). Conclusion: This study has documented that mechanical and thermal painful tonic stimuli applied to the craniofacial region can evoke diffuse noxious inhibitory control (DNIC)-like effects in the craniofacial region as well as spinally innervated areas, but without sex differences. Keywords: DNIC, human experimental pain models, sensory physiology, trigeminal pain

Aims: To estimate the clinically important change (CIC) on a 100-mm visual analog scale for pain intensity (VAS-PI) by relating it to the patient's global impression of change (PGIC) in patients with chronic temporomandibular disorder (TMD) pain and to assess the dependency of the CIC on their baseline pain scores. Methods: Data from a prospective cohort study with 588 patients with chronic TMD pain were analyzed. The CIC was estimated over a 3-month period, and receiver operating characteristic methods were used to assess the optimal cut-off point. The PGIC category of "much improved" served as an external criterion. Dependency of absolute and percent change on baseline VAS-PI scores was determined by linear regression analysis. Results: A VAS-PI change score of -19.5 mm and a percent change score of -37.9% were best associated with the concept of CIC. Since patients with high baseline pain required greater absolute reductions in pain to reach a clinically important improvement, percent change scores performed better in classifying improved patients. Conclusion: Providing a standard definition of the CIC adds to the interpretability of study results, ie, the estimates will aid in understanding individual patient outcomes. Keywords: chronic pain, minimal clinically important change, temporomandibular disorder

Aims: To estimate the prevalence of symptoms of temporomandibular disorders (TMD) as a function of age and gender, in a representative urban sample from the Brazilian population. Methods: A total of 1,230 inhabitants (51.5% women) aged 15 to 65 years were interviewed by a validated phone survey. Sample size had been previously calculated. TMD symptoms were assessed through five questions, as recommended by the American Academy of Orofacial Pain, in an attempt to identify possible TMD. Data were derived by age and gender. Prevalence of each TMD symptom, and of combination of symptoms, was calculated. Results: At least one TMD symptom was reported by 39.2% of the individuals. Pain related to TMD was noted by 25.6% of the population. Temporomandibular joint (TMJ) sound was the most common symptom of TMD, followed by TMJ pain and masticatory muscle pain. All symptoms were more prevalent in women than in men. With men used as the reference, a relative risk (RR) of at least one TMD symptom in women was 1.31 (95% confidence interval [CI] = 1.14 to 1.52). When at least two symptoms were present, the RR was 1.93 (95% CI = 1.49 to 2.51). For three or more TMD symptoms, the RR was 2.49 (95% CI = 1.67 to 3.71). Women were also more likely than men to have TMD pain (RR = 1.78; 9% CI = 1.45 to 2.18). Conclusion: Individual symptoms, as well as a combination of TMD symptoms, are prevalent in the Brazilian urban population and are more frequent in women than in men. Additional studies should focus on risk factors for and relevance of TMD for the sufferers. Keywords: epidemiology, facial pain, prevalence, temporomandibular joint

Aims: To identify the effect of unmet dental treatment needs and socioeconomic and sociodemographic variables on the patterns of dental visits in the presence of dental pain in 6- to 12-year-old Mexican schoolchildren. Methods: A case-control study included 379 patients that had a dental visit because of dental pain in the 12 months preceding this study and 1,137 controls. Mothers and/or guardians supplied sociodemographic, socioeconomic, and oral health-related information through a questionnaire. The profiles of unmet dental needs and of oral hygiene were ascertained by means of a standardized dental examination administered to participating children. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated with logistic regression. Results: Higher unmet dental needs and lack of health insurance were associated with the experience of dental visits because of dental pain in the preceding 12 months. Boys who attended public schools had a 70% (95% CI = 1.29 to 2.23) higher probability of having had a dental visit in which dental pain was one of the main reasons for attendance, compared to boys attending private schools. The effect for girls was only 28% (95% CI = 1.10 to 1.50) higher for girls attending a public school, compared to girls attending private schools. Older children had a higher occurrence of dental visits because of dental pain than younger children. Conclusions: While higher unmet dental needs and lack of health insurance were strong predictors of having had dental visits because of dental pain in the preceding 12 months, some socioeconomic variables and sociodemographic variables modified these relationships. Keywords: case-control study, dental caries, dental pain, Mexico, socioeconomic status, treatment needs, utilization of health services

Aims: To assess the prevalence of primary headaches (HA) in adults with temporomandibular disorders (TMD) who were assessed in a specialty orofacial pain clinic, as well as in controls without TMD. Methods: The sample consisted of 158 individuals with TMD seen at a university-based specialty clinic, as well as 68 controls. The Research Diagnostic Criteria for TMD were used to diagnose the TMD patients. HAs were assessed using a structured interview and classified according to the Second Edition of the International Classification for Headache Disorders. Data were analyzed by chi-square tests with a significance level of 5% and odds ratio (OR) tests with a 95% confidence interval (CI). Results: HAs occurred in 45.6% of the control group (30.9% had migraine and 14.7% had tension-type headache [TTH]) and in 85.5% of individuals with TMD. Among individuals with TMD, migraine was the most prevalent primary HA (55.3%), followed by TTH (30.2%); 14.5% had no HA. In contrast to controls, the odds ratio (OR) for HA in those with TMD was 7.05 (95% confidence interval [CI] = 3.65-13.61; P = .000), for migraine, the OR was 2.76 (95% CI = 1.50-5.06; P = .001), and for TTH, the OR was 2.51 (95% CI = 1.18-5.35; P = .014). Myofascial pain/arthralgia was the most common TMD diagnosis (53.2%). The presence of HA or specific HAs was not associated with the time since the onset of TMD (P = .714). However, migraine frequency was positively associated with TMD pain severity (P = .000). Conclusion: TMD was associated with increased primary HA prevalence rates. Migraine was the most common primary HA diagnosis in individuals with TMD. Keywords: facial pain, migraine, prevalence, temporomandibular joint, tension-type headache

Aims: To investigate the effect of low-level laser therapy (LLLT) on experimentally induced inflammation in retrodiscal tissues of the rabbit temporo-mandibular joint (TMJ) using scintigraphic imaging. Methods: Eleven male New Zealand rabbits were included in this study. Six randomly selected rabbits were imaged to provide normal joint images (normal group) before the initiation of the experiment. A 5% formalin solution was locally injected into both right and left TMJs of all rabbits. Subsequently, Ga-Al-As laser (wavelength: 815 nm; energy density: 12 J/cm2; output power: 250 mW) was applied for 48 seconds. The treatment was performed six times for 2 weeks to the left TMJ of all rabbits. The right TMJs of the rabbits were used as the control (nontreated) TMJ group, while left TMJs were used as the treated TMJ group. Static images of TMJ were taken at 24 hours, 7 days, and 14 days after the beginning of the treatment. The images of all TMJs were taken in the posteroanterior direction with the rabbit under sedation and its mouth open. The Mann-Whitney U test was used to compare group differences, and intragroup differences were determined by the Friedman test and Wilcoxon sign test. Results: Significant differences were found between normal and both the control and treated TMJ groups. A reduction of inflammation in both treated and control TMJ groups was obtained, but there was no statistically significant difference between the groups. Conclusion: Under the conditions used in this study, quantitative scintigraphic measurements of TMJ inflammation of the treated TMJ group decreased but did not differ significantly from those of the control TMJ group. Keywords: aseptic inflammation, experimental study, low-level laser therapy, scintigraphy, temporomandibular joint

Aims: To develop a rat model of temporomandibular joint (TMJ) pain and to characterize in it the development and temporal response of behavioral hypersensitivity as well as to evaluate if and to what extent a loading protocol is associated with histological changes in the TMJ consistent with osteoarthritic pathology. Methods: A novel rat model of TMJ pain was developed using a noninvasive, mechanical loading protocol. Rats were exposed to steady mouth-opening for 7 days (2 N force, 1 hour/day), and mechanical hyperalgesia (increased pain response) was measured during the loading period and for 14 days thereafter. Histological modifications in the joint cartilage were also evaluated. Outcomes for the mouth-opening exposure were compared to age-matched controls. Thresholds for evoking responses were compared using a ranked ANOVA with repeated measures. Results: Increased mechanical hypersensitivity in the temporomandibular region developed during daily loading and persisted even after the termination of the loading protocol. Histologic characterization revealed thinning of the cartilaginous structures of the joint and irregular zonal cellular arrangements in the condylar cartilage of rats subjected to the daily loading protocol. Conclusion: The injury model presented here is the first to demonstrate mechanically-induced behavioral hypersensitivity accompanied by osteoarthritic pathology in the TMJ. Keywords: collagen, condylar cartilage, glycosaminoglycans, osteoarthritis, pain

Aims: To evaluate the antinociceptive effects of citronellal (CTL) on formalin-, capsaicin-, and glutamate-induced orofacial nociception in mice and to investigate whether such effects might involve a change in neural excitability. Methods: Male mice were pretreated with CTL (50, 100, and 200 mg/kg, ip), morphine (5 mg/kg, ip), or vehicle (distilled water + one drop of Tween 80 0.2%) before formalin (20 µL, 2%), capsaicin (20 µL, 2.5 µg) or glutamate (40 µL, 25 µM) injection into the right vibrissa. Sciatic nerve recordings were made using the single sucrose gap technique in rats. The data obtained were analyzed by ANOVA followed by Dunnett's test for the behavioral analyses and by the Student t test for CAP evaluation. Results: Pretreatment with CTL was effective in reducing nociceptive face-rubbing behavior in both phases of the formalin test, which was also naloxone-sensitive. CTL produced significantly antinociceptive effect at all doses in the capsaicin- and glutamate- tests. Rota-rod testing indicated that such results were unlikely to be provoked by motor abnormality. Recordings using the single sucrose gap technique revealed that CTL (10 mM) could reduce the excitability of the isolated sciatic nerve through a diminution of the compound action potential amplitude by about 42.4% from control recordings. Conclusion: These results suggest that CTL might represent an important tool for management and/or treatment of orofacial pain. Keywords: antinociceptive, citronellal, neuronal excitability, orofacial pain, single sucrose gap technique

An osteoma is a benign tumor essentially restricted to the craniofacial skeleton. Osteomas occur most frequently in the frontal, ethmoid, and maxillary sinuses, and rarely affect the glenoid fossa. Osteomas are usually pain-free and remain silent, ie, symptom-free, for many years but may lead to occlusal changes. The report describes the case of an adult man with an osteoma who presented with a chief complaint of malocclusion and who was misdiagnosed. The case points to the diagnostic reasoning necessary to arrive at a correct diagnosis, especially when signs and symptoms, as well as pathology, are rare, eg, not familiar to the clinician. Keywords: bone neoplasms, diagnostic errors, osteoma, temporomandibular joint, temporomandibular joint disorders