Britt Hedenberg-Magnusson

THE LEVEL OF SEROTONIN IN THE SUPERFICIAL MASSETER MUSCLE IN RELATION TO LOCAL PAIN AND ALLODYNIA

The aim of this study was to investigate if serotonin is present in the human masseter muscle and if so, whether it is involved in the modulation of local muscle pain or allodynia. Thirty-five patients with pain and tenderness of the masseter muscle as well as ten healthy individuals were included in the study. Of the patients, 18 suffered from fibromyalgia and 17 had localized myalgia, e.g. myofascial pain in the temporomandibular system. The participants were examined clinically with special consideration to the masseter muscle and the pressure pain threshold as well as tolerance levels of this muscle were assessed. Intramuscular microdialysis was performed in order to sample serotonin and a venous blood sample was collected for analysis of the serum level of serotonin. Serotonin was present in the masseter muscle and the level was significantly higher in the initial sample than in the sample collected during steady state. The level of serotonin in the masseter muscle in relation to the level of serotonin in the blood serum was calculated. This fraction of serotonin was higher in the patients with fibromyalgia than in healthy individuals and high level of serotonin was associated with pain as well as allodynia of the masseter muscle. In conclusion, the results of this study show that serotonin is present in the human masseter muscle both immediately following puncture and in a subsequent steady state and that it is associated with pain and allodynia. The origin of the serotonin seems partly to be the blood, but our results indicate that peripheral release also occurs.

Symptoms and signs of temporomandibular disorders in patients with fibromyalgia and local myalgia of the temporomandibular system. A comparative study.

Symptoms and signs of temporomandibular disorders (TMD) in 46 patients were investigated and compared with those in 20 healthy individuals. Twenty-three patients had fibromyalgia (FM) and 23 had local myalgia (LM). Facial pain was assessed with a visual analogue scale, and a clinical examination was performed, including maximum voluntary mouth opening, temporomandibular joint sounds, tenderness to digital palpation in the masticatory muscles, pressure pain threshold and tolerance level of the superficial masseter muscle, intramuscular temperature, and maximum voluntary bite force. There was a difference in the number of tender muscles between the groups. Pressure pain threshold and tolerance levels were lower in the FM than in the LM group, whereas both showed lower values than a control group (C). The intramuscular temperature and maximum voluntary mouth opening were lower in the patient groups than in the C group. TMJ sounds showed a difference between all three groups. In conclusion, this study shows that FM patients frequently have TMD and indicates several differences between patients with FM and LM with regard to clinical variables.

Efficacy of botulinum toxin type A for treatment of persistent myofascial TMD pain: a randomized, controlled, double-blind multicenter study

&NA; Evidence of an effect by botulinum toxins is still lacking for most pain conditions. In the present randomized, placebo‐controlled, crossover multicenter study, the efficacy of botulinum toxin type A (BTX‐A) was investigated in patients with persistent myofascial temporomandibular disorders (TMD). Twenty‐one patients with myofascial TMD without adequate pain relief after conventional treatment participated. A total of 50 U of BTX‐A or isotonic saline (control) was randomly injected into 3 standardized sites of the painful masseter muscles. Follow‐up was performed after 1 and 3 months, followed by a 1‐month washout period, after which crossover occurred. Pain intensity at rest was the primary outcome measure, while physical and emotional function, global improvement, side effects, and clinical measures were additional outcome measures. There was no main difference between drugs (ANOVA; P = .163), but there was a significant time effect (P < .001), so BTX‐A reduced mean (SD) percent change of pain intensity by 30 (33%) after 1 month and by 23 (30%) after 3 months compared to 11 (40%) and 4 (33%) for saline. The number of patients who received a 30% pain reduction was not significantly larger for BTX‐A than after saline at any follow‐up visit. The number needed to treat was 11 after 1 month and 7 after 3 months. There were no significant changes after treatment in any other outcome measures, with the exception of pain on palpation, which decreased 3 months after saline injection (P < .05). These results do not indicate a clinical relevant effect of BTX‐A in patients with persistent myofascial TMD pain. Botulinum toxin type A is not an effective adjunct to conventional treatment in persistent myofascial temporomandibular disorders.

Pain mediation by prostaglandin E2 and leukotriene B4 in the human masseter muscle

The pathophysiology behind chronic pain from masticatory muscles is unclear. Our hypothesis was that this pain is of inflammatory origin and associated with release of inflammatory mediators. The aim of this study was therefore to investigate the presence of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the masseter muscle and plasma and their relation to myalgia. Nineteen patients with fibromyalgia, 19 with local myalgia of the masseter muscle, and 11 healthy individuals were examined with regard to local muscular pain intensity at rest and pressure pain threshold. Inclusion criteria were masseter muscle pain for at least 3 months and masseter muscle tenderness on digital palpation. Samples were obtained from the masseter muscle by microdialysis, and the dialysates and venous blood samples were analyzed with regard to PGE2 and LTB4 concentration. Intramuscular levels were found in all groups, with significantly higher levels of LTB4 in the patients with fibromyalgia, in whom PGE2 was positively correlated to muscular pain. In the healthy individuals PGE2 was negatively correlated to pressure pain threshold. In both patient groups but not in the healthy individuals LTB4 increased during the consecutive samplings. PGE2 and LTB4 were detectable in the plasma of all groups. In conclusion, both PGE2 and LTB4 were found in the human masseter muscle. LTB4 levels are increased on needle trauma in patients with myalgia. PGE2 levels are related to muscular pain in patients with fibromyalgia. Masseter muscle pain therefore seems to be partly of peripheral inflammatory origin in fibromyalgia.

Effect on prostaglandin E2 and leukotriene B4 levels by local administration of glucocorticoid in human masseter muscle myalgia

Our aim was to determine whether masseter muscle (M) and plasma (P) levels of prostaglandin E2 (PGE2) or leukotriene B4 (LTB4) are influenced by local glucocorticoid administration and whether such changes would be associated with corresponding changes in local pain or hyperalgesia. Eighteen patients with fibromyalgia and 15 with local masseter myalgia were examined immediately before and 2 weeks after intramuscular administration of glucocorticoid with regard to masseter muscle resting pain and tenderness to palpation, pressure pain threshold, maximum voluntary mouth opening (MVM), and pain on maximum voluntary mouth opening. The primary criteria for inclusion were presence of pain for a period of at least 3 months and tenderness to digital palpation in the masseter muscle region. At both visits microdialysis samples were obtained from the masseter muscle, and venous blood was collected for analysis of PGE2 and LTB4. Dialysate levels of M-PGE2 did not change significantly after glucocorticoid administration, but reduction of masseter resting pain and increase of MVM were associated with decrease of M-PGE2 in the patients with fibromyalgia. Dialysate levels of M-LTB4 increased in both groups. In the patients with local myalgia the plasma level of LTB4 also increased, and this increase was associated with a decrease of pain and masseter tenderness. In conclusion, this study shows that reduction of masseter level of PGE2 after intramuscular glucocorticoid administration is associated with a decrease of resting pain in patients with fibromyalgia. In addition, the masseter muscle level of LTB4 increases in patients with fibromyalgia and local myalgia.

Orofacial pain and dysfunction in children with juvenile idiopathic arthritis: a case–control study

Objectives: Juvenile idiopathic arthritis (JIA) frequently causes temporomandibular joint (TMJ) inflammation. The aim of this study was to evaluate the presence of orofacial pain and temporomandibular dysfunction in patients with JIA and controls. Methods. Forty-one patients with JIA and 41 age- and sex-matched healthy controls participated. Subjects were asked about facial pain variables and their influence on daily life. A clinical examination was performed. Panoramic radiograph and medical data were extracted from the records. Results: Thirty-three of the JIA patients reported TMJ or facial pain compared to four of the controls (p < 0.001). Nine of the JIA patients, compared to none of the controls, reported that their orofacial symptoms influenced daily life severely (p < 0.001). Clinical findings were more prevalent in JIA (p < 0.001). The assessments of disease activity correlated to palpation pain of jaw muscles (p < 0.001) whereas the presence of structural TMJ changes correlated to reduced jaw opening (p < 0.001). Conclusions: TMJ pain was prevalent in patients with JIA and influenced daily life severely for nearly a quarter of them. Collaboration between medical and dental care is therefore important.

Effects of isometric contraction on intramuscular level of neuropeptide Y and local pain perception.

Objective. The release of neuropeptide Y (NPY) is reported to increase in ischemic conditions and may thus be involved in chronic myalgia. The purpose of this study was to investigate the effect of isometric contraction on intramuscular levels of NPY in relation to local pain development. Material and methods. Intramuscular microdialysis was performed in the masseter and trapezius muscles to determine NPY levels before, during, and after isometric contraction in 16 healthy females. Pain intensity was assessed simultaneously with VAS. Repeated measures ANOVA, t-test, and Pearson correlation analysis were used for statistical analyses. Results. The level of NPY in the trapezius muscle was increased during and after contraction, while there was no change in the masseter muscle. The level of NPY before contraction was higher in the masseter muscle than in the trapezius muscle, and the levels in the two muscles were correlated before and during contraction. Low-level pain in both muscles after probe insertion increased significantly during contraction, but the pain was not correlated to the NPY level. Conclusions. Pain is developed in the trapezius and masseter muscles during repeated isometric contraction. The NPY level is increased in the trapezius muscle but is not associated with the pain development.

Temporomandibular condylar alterations in juvenile idiopathic arthritis most common in longitudinally severe disease despite medical treatment

BackgroundJuvenile idiopathic arthritis (JIA) is an autoimmune, heterogeneous disease and the temporomandibular joint (TMJ) can be affected, with consequences for mandibular growth and function. The aim of this study was to evaluate the importance of longitudinal medical treatment and the burden of disease activity on the development of temporomandibular condylar alterations as judged on panoramic radiographs.MethodsThe study was a retrospective evaluation of dental and medical records in consecutive JIA patients referred to three specialist dental clinics in Sweden during an eight-year period. Data on the total pharmacological treatment and disease activity were evaluated longitudinally from disease onset to the time of the panoramic examination, during a median observation period of 2.5 years. The radiographs were analysed in terms of structural and shape alterations in the condyles and judged dichotomously.ResultsPanoramic examinations were analysed in 158 patients from 266 referrals diagnosed with JIA. Condylar alterations (shape or structural) were seen in 68 patients (43%). Patients with condylar alterations were more extensively treated over time compared with those without condylar alterations. Powerful disease activity and/or potent medication at any time during the course of the disease implied an increased risk of alterations.ConclusionsPatients with JIA who require more intensive medication over time run the greatest risk of condylar alterations. As yet, current medical programmes have not been specified for the TMJ and more knowledge in this area is needed.

The proteomic profile of whole and glandular saliva in healthy pain-free subjects

Determination of the variability in the salivary proteome is a prerequisite for the development of saliva as a diagnostic and prognostic tool in particular physiological states. In this context, it is important that technical variability induced by sample collection and processing is kept at minimum to be able to reproducibly assess variability in states of health and disease. In the current study, the proteome profile in unstimulated and stimulated whole, parotid and sublingual saliva was investigated using two-dimensional gel electrophoresis. Saliva samples were structurally collected from ten examined and characterized healthy individuals during the exactly same conditions. The results demonstrated that different collection methods provide clear differences in the snapshot of the salivary proteome and also in the relative amount of specific proteins. The variable nature of the salivary proteome suggests that different approaches may have to be adopted when studying its composition or its possible role as an indicator for particular physiological states. The results emphasize the importance of consistency when collecting saliva samples for proteomic analysis.

Effect of local glucocorticoid injection on masseter muscle level of serotonin in patients with chronic myalgia

The aim of this study was to compare the effects on the level of serotonin (5-HT) in the masseter muscle by intramuscular glucocorticoid (GC) administration in patients with fibromyalgia (FM) and localized myalgia (LM), as well as to determine associated changes in pain, tenderness, and microcirculation. The study comprised 22 patients with pain and tenderness in the masseter muscle region. Ten patients (all women) had FNI, and 12 (1 man and 11 women) had LM involving the temporomandibular system. The patients were examined clinically and by microdialysis at 2 visits 2-3 weeks apart and received local glucocorticoid treatment at the first visit. The ratio (S1/S2) between the initial level of 5-HT (S1) and steady state level (S2) was used as a relative measure of the intramuscular release of 5-HT. This ratio decreased significantly after treatment in the FM group. In the FM group there was also a negative correlation regarding changes between visits of 5-HT and changes of intramuscular temperature. In the LM group there was a negative correlation regarding changes between visits of 5-HT and changes of pressure pain threshold and pressure pain tolerance level. This study indicates that there is a reduction of the ratio between initial 5-HT and steady state level in the painful masseter muscle after intramuscular GC administration to FM patients, a reduction not present in the LM patients. In addition, 5-HT seems to be involved in the modulation of local muscle microcirculation in FM patients and in hyperalgesia in LM patients.