Sigvard Kopp

Thickness of the soft tissue layers and the articular disk in the temporomandibular joint.

Out of 115 right temporomandibular joints from Swedish subjects aged 1 day to 93 years, 48 joints without any gross sign of arthrosis or deviation in form were examined histologically. The joint components were cut sagittaly, each into four parts. Histological sections were made of the condyle, the temporal component and of the articular disk. The total thickness of the soft tissue layers was measured in decalcified sections, cut from the medio-central and lateral parts of the condyle and the temporal component and from the medial, medio-central, latero-central and lateral regions of the disk. In the medio-central sections from the condyle and temporal component the thickness of the fibrous connective tissue layer i.e. the surface layer was also registered. The soft tissue layers were thickest in the condyle superiorly, about 0.4-0.5 mm, in the temporal component on the postero-inferior slope of the articular tubercle, about 0.5 mm, and in the disk posteriorly about 2.9 mm. In the roof of the fossa it was only 0.1 mm. The soft tissue layers on the condyle as well as the disk were thinner laterally while the corresponding tissue in the temporal component was thicker laterally. The thickness of the soft tissue layers seem to reflect the growth and functional load to which the joint is exposed.

The short-term effect of intra-articular injections of sodium hyaluronate and corticosteroid on temporomandibular joint pain and dysfunction.

The short-term effect of intra-articular injections of sodium hyaluronate and a corticosteroid (betamethasone) was compared in a sample of 33 patients who had pain and tenderness to palpation in the temporomandibular joint of at least six months duration that had not responded to previous conservative treatment. The two drugs were randomly allocated to the patients. A volume of 0.5 ml of the drug was injected twice into the superior joint compartment of the TMJ with a two-week interval between injections. The effect on subjective symptoms, clinical signs, and bite force was assessed. Both drugs reduced the symptoms and signs significantly, and no statistically significant difference in effect could be found between drugs in this regard. The results indicate that the difference between the drugs in terms of short-term therapeutic effects is small, and that sodium hyaluronate could be used as an alternative to corticosteroid for patients who have signs of TMJ inflammation, especially for those who have symptomatic osteoarthrosis.

A three-year follow-up of patients with reciprocal temporomandibular joint clicking

It has been suggested in the literature that reciprocal temporomandibular joint clicking progresses to locking, but little information is available on the longitudinal course of this stage of internal derangement. Seventy patients with reciprocal clicking were therefore followed for 3 years. Reciprocal clicking remained unchanged in fifty patients (71%) and disappeared in twenty patients (29%). Fourteen patients (20%), in whom clicking disappeared, attained normal mouth opening, whereas locking developed in six patients (9%). At the initial examination, these six patients had more pain, more frequent joint tenderness, greater frequency of missing molar support and more often dental abrasion on the affected side than the patients who did not develop locking. It was concluded that reciprocal clicking does not usually progress to locking. However, locking is more likely to occur in patients who initially have pronounced pain, joint tenderness, dental abrasion, and no molar support on the affected side.

Long-term effect of intra-articular injections of sodium hyaluronate and corticosteriod on temporomandibular joint arthritis☆

The long-term effect of intra-articular injections of sodium hyaluronate and corticosteroid (betamethasone) was compared in a sample of 24 patients who had pain and tenderness to palpation in the temporomandibular joint (TMJ arthritis) of at least six months duration, and who had not responded to conservative treatment. The two drugs were randomly allocated to the patients. The drugs, 0.5 ml, were injected twice into the superior joint compartment of the TMJ with a two-week interval between injections. The effect on subjective symptoms, clinical signs, and bite force was assessed. At the one and two-year follow-ups both the hyaluronate-and the corticosteroid-group had significantly reduced subjective symptoms as well as clinical signs, and the maximum voluntary bite force was significantly increased. The differences in effect between treatments were not statistically significant. It was concluded that both drugs have a significant long-term effect on chronic arthritis of the TMJ and that either of the drugs can be helpful; however, sodium hyaluronate might be the best alternative due to the least risk for side effects.

The influence of neuropeptides, serotonin, and interleukin 1β on temporomandibular joint pain and inflammation

PURPOSE This article describes the possible role of various peptides in producing pain and inflammation in the temporomandibular joint (TMJ). MATERIAL AND METHODS Current research findings on the spectrophotometric quantification of TMJ synovial fluid for neuropeptide Y (NPY), serotonin (5HT), and interleukin-1beta (IL-1beta) are presented. FINDINGS NPY was found in high levels in the synovial fluid of arthritic TMJs with resting pain, and serotonin (5-HT) was found in patients with pain perceived on mandibular movement. These pain-related mediators were also associated with restricted mandibular mobility. Interleukin-1beta (IL-1beta) was found to be strongly associated with hyperalgesia over the TMJ as well as resting pain. Anterior open bite as a clinical sign of joint destruction was found to be associated with high levels of NPY and IL-1beta in the synovial fluid. IL-1beta was also related to the radiographic signs of joint destruction. CONCLUSIONS Interaction between the peripheral nervous system (sensory and sympathetic nerves) and the immune system is probably of importance for the modulation of pain and inflammation in the TMJ, but this subject has to be investigated further with experimental clinical studies.

Tumor necrosis factor-alpha in synovial fluid and plasma from patients with chronic connective tissue disease and its relation to temporomandibular joint pain.

PURPOSE The purpose of this study was to determine the level of tumor necrosis factor-alpha (TNF-alpha) in the temporomandibular joint (TMJ) synovial fluid (SF-TNF-alpha) and blood plasma (P-TNF-alpha) of patients with chronic inflammatory connective tissue disease and investigate its relation to TMJ pain, hyperalgesia, and allodynia. PATIENTS AND METHODS Twenty-four patients with a diagnosis of chronic inflammatory connective tissue disease and TMJ pain were included in the study. Visual analog scale, tenderness of the TMJ, and pain at mandibular movements were registered, and the pressure pain threshold and pressure pain tolerance levels were measured. TMJ synovial fluid samples and blood plasma were analyzed for TNF-alpha and the levels related to TMJ pain, hyperalgesia, and allodynia. RESULTS TNF-alpha was present in the TMJ synovial fluid of 8 of 24 patients at levels significantly exceeding those in plasma at the same visit. The presence of SF-TNF-alpha showed a significant positive correlation to TMJ pain at maximum voluntary mouth opening and tenderness to posterior palpation of the TMJ. CONCLUSION Local production of TNF-alpha occurs in the TMJ synovium of patients with chronic inflammatory connective tissue disease. Pain on mandibular movement and tenderness on posterior palpation (allodynia) of the TMJ is related to the level of SF-TNF-alpha.

Interleukin-1β in synovial fluid from the arthritic temporomandibular joint and its relation to pain, mobility, and anterior open bite

Abstract Purpose: The purpose of this study was to investigate whether interleukin-1β in synovial fluid or blood plasma is involved in the development of pain or hyperalgesia of the temporomandibular joint (TMJ), as well as reduced mandibular mobility and anterior open bite. Patients and Methods: Twenty-nine patients with TMJ arthritis and seven healthy subjects were studied. VAS measurement of TMJ tenderness on palpation of the TMJ (TDP), TMJ pressure pain threshold and tolerance level (PPTL), mandibular mobility, pain during joint movements, and degree of anterior open bite (AOB) were assessed. IL-1β levels were analyzed in TMJ synovial fluid (SF-IL-1β) and blood samples and correlated with the preceding factors. Results: SF-IL-1β showed significant positive correlations with VAS measurement of pain, TDP, and AOB and a negative correlation with PPTL. Conclusions: This study indicates that IL-1β in the synovial fluid is associated with pain and hyperalgesia in the TMJ region as well as an anterior open bite. Concerning the latter condition, IL-1β seems to be a warning signal of tissue destruction.

Pain and allodynia/hyperalgesia induced by intramuscular injection of serotonin in patients with fibromyalgia and healthy individuals

Abstract The aim of this study was to investigate the effect of injection of serotonin (5‐HT) into the masseter muscle on pain and allodynia/hyperalgesia. Twelve female patients with fibromyalgia (FM) and 12 age‐matched female healthy individuals (HI) participated in the study. The current pain intensity (CPI) and the pressure pain threshold (PPT) of the superficial masseter muscles were assessed bilaterally. 5‐HT in one of three randomized concentrations (10−3, 10−5, 10−7 M) or isotonic saline was then injected into either of the two masseter muscles in a double‐blind manner. After the injections the CPI and PPT were recorded ten times during 30 min. The injections were repeated twice with the other concentrations of 5‐HT after 1 and 2 weeks, respectively. In the FM‐group there was a non‐significant increase of CPI after injection that lasted during the entire 30‐min period irrespective of whether 5‐HT or saline was injected. Neither did the PPT change significantly. In the HI‐group pain developed significantly after injection irrespective of whether 5‐HT or saline was injected, but significantly more so after 5‐HT at 10−3 M than saline injection. CPI decreased quickly and then remained on a very low level for most of the experiment. 5‐HT at both 10−5 M and 10−3 M caused a significantly greater decrease of PPT than saline. In conclusion, our results show that 5‐HT injected into the masseter muscle of healthy female subjects elicits pain and allodynia/hyperalgesia, while no such responses occur in patients with fibromyalgia.

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.