Degenerative Disease of the Temporomandibular Joint and Pain-Dysfunction Syndrome

It is proposed that pain-dysfunction syndrome and degenerative disease ofthe temporomandibular joint may both be expressions of the same problem, i.e, repetitive overload of the joint system. Acceptance of this proposal will explain the contrasting, although often successful, methods of treatment.

Estradiol upregulates voltage-gated sodium channel 1.7 in trigeminal ganglion contributing to hyperalgesia of inflamed TMJ

BACKGROUND

Temporomandibular disorders (TMDs) have the highest prevalence in women of reproductive age. The role of estrogen in TMDs and especially in TMDs related pain is not fully elucidated. Voltage-gated sodium channel 1.7 (Nav1.7) plays a prominent role in pain perception and Nav1.7 in trigeminal ganglion (TG) is involved in the hyperalgesia of inflamed Temporomandibular joint (TMJ). Whether estrogen could upregulate trigeminal ganglionic Nav1.7 expression to enhance hyperalgesia of inflamed TMJ remains to be explored.

METHODS

Estrous cycle and plasma levels of 17β-estradiol in female rats were evaluated with vaginal smear and enzyme linked immunosorbent assay, respectively. Female rats were ovariectomized and treated with 17β-estradiol at 0 μg, 20 μg and 80 μg, respectively, for 10 days. TMJ inflammation was induced using complete Freund's adjuvant. Head withdrawal thresholds and food intake were measured to evaluate the TMJ nociceptive responses. The expression of Nav1.7 in TG was examined using real-time PCR and western blot. The activity of Nav1.7 promoter was examined using luciferase reporter assay. The locations of estrogen receptors (ERα and ERβ), the G protein coupled estrogen receptor (GPR30), and Nav1.7 in TG were examined using immunohistofluorescence.

RESULTS

Upregulation of Nav1.7 in TG and decrease in head withdrawal threshold were observed with the highest plasma 17β-estradiol in the proestrus of female rats. Ovariectomized rats treated with 80 μg 17β-estradiol showed upregulation of Nav1.7 in TG and decrease in head withdrawal threshold as compared with that of the control or ovariectomized rats treated with 0 μg or 20 μg. Moreover, 17β-estradiol dose-dependently potentiated TMJ inflammation-induced upregulation of Nav1.7 in TG and also enhanced TMJ inflammation-induced decrease of head withdrawal threshold in ovariectomized rats. In addition, the estrogen receptor antagonist, ICI 182,780, partially blocked the 17β-estradiol effect on Nav1.7 expression and head withdrawal threshold in ovariectomized rats. ERα and ERβ, but not GPR30, were mostly co-localized with Nav1.7 in neurons in TG. In the nerve growth factor-induced and ERα-transfected PC12 cells, 17β-estradiol dose-dependently enhanced Nav1.7 promoter activity, whereas mutations of the estrogen response element at -1269/-1282 and -1214/-1227 in the promoter completely abolished its effect on the promoter activity.

CONCLUSION

Estradiol could upregulate trigeminal ganglionic Nav1.7 expression to contribute to hyperalgesia of inflamed TMJ.

[Features of the hormonal status in patients with temporomandibular joint dysfunction and class II malocclusion]

The article presents data on androgen levels in female patients with temporomandibular joint (TMJ) dysfunction of varying degree and class II malocclusion. The study revealed significant correlation between degenerative and inflammatory TMJ changes and androgens level in patients with stigmas of connective tissue dysplasia (p<0.05), probably due to indirect proinflammatory action of androgens as they stimulate inflammatory mediators expression.

Differential diagnostics of pain in the course of trigeminal neuralgia and temporomandibular joint dysfunction

Chronic oral and facial pain syndromes are an indication for intervention of physicians of numerous medical specialties, while the complex nature of these complaints warrants interdisciplinary diagnostic and therapeutic approach. Oftentimes, lack of proper differentiation of pain associated with pathological changes of the surrounding tissues, neurogenic pain, vascular pain, or radiating pain from idiopathic facial pain leads to improper treatment. The objective of the paper is to provide detailed characterization of pain developing in the natural history of trigeminal neuralgia and temporomandibular joint dysfunction, with particular focus on similarities accounting for the difficulties in diagnosis and treatment as well as on differences between both types of pain. It might seem that trigeminal neuralgia can be easily differentiated from temporomandibular joint dysfunction due to the acute, piercing, and stabbing nature of neuralgic pain occurring at a single facial location to spread along the course of the nerve on one side, sometimes a dozen or so times a day, without forewarning periods. Both forms differ significantly in the character and intensity of pain. The exact analysis of the nature, intensity, and duration of pain may be crucial for the differential diagnostics of the disorders of our interest.

Correlation between articular eminence steepness measured with cone-beam computed tomography and clinical dysfunction index in patients with temporomandibular joint dysfunction

OBJECTIVE

The purpose of this study was to investigate the correlation between articular eminence steepness and clinical dysfunction index (Di) in patients with temporomandibular joint dysfunction (TMD) using cone-beam computed tomography (CBCT).

STUDY DESIGN

In this study, CBCT images of 60 temporomandibular joints in 30 patients with TMD were evaluated. The eminence inclination values were measured on CBCT images. Patients were subdivided into 3 groups based on Helkimo's clinical Di. The data were analyzed using Spearman's rho correlation coefficient test.

RESULTS

The results of the present study did not confirm any significant differences in the values of articular eminence inclinations among the 3 groups (P value >.05).

CONCLUSION

Based on the present study, there is no apparent relationship between the articular eminence inclination and the clinical Di in patients with TMD.

[The peculiarities of petrotympanic fissure topography in Costen syndrome and possible causes of its development]

A complex study of morphometric characteristics of the articular surfaces of the temporomandibular joint and the examination of the peculiarities of the petrotympanic fissure topography were performed on 138 samples of skulls of adult individuals with intact occlusion, complete anodontia and different forms of cranial skull (dolicho-, meso- and brachicranial). No distinct differences in studied parameters were found between the studied groups. However, in the hypsicranial group the petrotympanic fissure was found to pass more often through the medial third of the mandibular fossa, which may be a predisposing anatomical factor for Costen syndrome. Due to the fact that in anodontia the parameters characterizing the articular surfaces of the temporomandibular joint, are significantly changed, the immediate cause of the Costen syndrome are the changes of the articular surfaces of the temporomandibular joint, primarily the reduction in the size of mandibular condyle, which is accompanied by its pathological displacement and compression of the chorda tympani.

Disc and condylar head position in the temporomandibular joint with and without disc displacement

The purpose of this study was to evaluate the difference between disc and condyle position between temporomandibular joints (TMJs) without disc displacement (DD) in asymptomatic volunteers, and patients who have DD in contralateral joints, respectively unilateral DD. Secondly, there were two TMJ groups which consisted of measurements from patients' symptomatic DD and volunteers with asymptomatic DD. The study included 79 TMJs of 40 patients with unilateral DD. In the group of 25 asymptomatic volunteers, 20 volunteers were without DD bilaterally (40 joints), while five had DD in at least one TMJ. All subjects were examined clinically and DD was confirmed by magnetic resonance imaging. Left and right TMJs were analysed independently for each participant based on their DD status (symptomatic, asymptomatic, and without DD). All asymptomatic TMJs did not have any clinical signs of TMJ functional abnormalities. There was a significant statistical difference between disc position among TMJs without DD in asymptomatic volunteers and TMJs without DD in patients (p = 0.016). Moreover, no significant differences were found between condyle position in the same groups of joints (p = 0.706). There were no significant differences in the DD position (p = 0.918) or condyle position (p = 0.453) between the group with asymptomatic volunteers' joints and the group with symptomatic patients' joints. There was a significant difference between patient and volunteers' joints without DD: the disc was positioned more anteriorly in patients' joints without DD than in joints of asymptomatic volunteers without DD.

Changes in regional gray and white matter volume in patients with myofascial-type temporomandibular disorders: a voxel-based morphometry study

AIMS

To use magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) to search for evidence of altered brain morphology in patients with temporomandibular disorders (TMD).

METHODS

Using VBM, regional gray and white matter volume was investigated in nine TMD patients and nine carefully matched healthy controls.

RESULTS

A decrease in gray matter volume occurred in the left anterior cingulate gyrus, in the right posterior cingulate gyrus, the right anterior insular cortex, left inferior frontal gyrus, as well as the superior temporal gyrus bilaterally in the TMD patients. Also, white matter analyses revealed decreases in regional white matter volume in the medial prefrontal cortex bilaterally in TMD patients.

CONCLUSION

These data support previous findings by showing that TMD, like other chronic pain states, is associated with changes in brain morphology in brain regions known to be part of the central pain system.

[Myogenous temporomandibular pain: treat with care!]

For the treatment of myogenous temporomandibular pain, a clinician can choose from among a wide variety of possibilities. Unfortunately, a paper summarizing the effectiveness of all these forms of treatment does not yet exist. The aim of this paper is to provide specific advice for dentists concerning the treatment of patients with myogenous temporomandibular pain by means of a systematic review of the relevant literature. The results of this review of the literature suggest that all forms of treatment selected, including treatment with placeboes, are equally effective in reducing myogenous temporomandibular pain. In order to avoid liability issues, it is advisable to choose for a restrained, reversible form of treatment. The dentist and the patient must, in this respect, be aware that the pain can continue after treatment (albeit at a reduced level) or can return after a period of time.

[Acupuncture combined with magnetic therapy for treatment of temple-jaw joint dysfunction]

OBJECTIVE

To compare clinical therapeutic effects of acupuncture combined with magnetic therapy and simple magnetic therapy on temple-jaw joint dysfunction.

METHODS

Eighty-two cases were randomly divided into an observation group (n = 52) and a control group (n = 30). The observation group was treated with acupuncture at Xiaguan (ST 7), Jiache (ST 6), Hegu (LI 4), etc. and AL-2 low frequency electromagnetic comprehensive treatment instrument; the control group was treated with AL-2 low frequency electromagnetic comprehensive treatment instrument.

RESULTS

The cured and markedly effective rate of 90.4% in the observation group was significantly better than 66.7% in the control group (P < 0.01), and the total effective rate of 98.1% in the observation group was significantly better than 86.7% in the control group (P < 0.05).

CONCLUSION

The therapeutic effect of acupuncture combined with magnetic therapy is significantly better than that of the simple magnetic therapy on temple-jaw joint dysfunction.

Magnetic resonance imaging evaluation of temporomandibular joint derangement in symptomatic and asymptomatic patients

OBJECTIVE

To highlight the importance of MRI in evaluation of the tempromandibular joint (TMJ).

METHODS

The MRI examination was performed at King Khalid University Hospital, Riyadh, Saudi Arabia with the approval from the local ethics committee, on 34 patients (68 joints) between January 2006 and November 2007, in which 10 were considered asymptomatic subjects (control). The remaining had symptoms and signs of TMJ pain or dysfunction, including limitation of movement and clicking. All our subjects were examined in both closed and open mouth position. Images were obtained by 1.5-T MRI system, in oblique sagittal plane utilizing 3 pulse sequences including T1 and T2 spin-echo, and spoiled gradient recall sequences. The evaluation of the meniscal disc configuration and position was carried out by 2 radiologists.

RESULTS

Sixteen out of 20 joints of asymptomatic subjects were normal. In the other 2 asymptomatic subjects, the MRI showed anterior disc displacement with reduction in 3 joints, and degenerative changes in 2 joints. Out of the 48 symptomatic joints, 26 (45%) joints were considered normal, while the other 22 joints showed anterior dislocation without reduction. Degenerative joint disease was also seen in 18 joints.

CONCLUSION

The MRI with the use of surface coils markedly improves the delineation of internal derangement of the TMJ, therefore, it enhanced the capability of detecting certain abnormalities, which proved to have a statistical significance in symptomatic patients.

Occlusion in patients with temporomandibular joint anterior disk displacement

The aim of this study was to determine the correlation between the static and dynamic occlusal factors in patients with anterior disk displacement (DD) and to compare it with occlusion in asymptomatic individuals. The study included a group of 40 patients with DD (median age 35.5) and a control group of 25 students of dental medicine (median age 23.4). In all subjects, the position, i.e. DD was determined by magnetic resonance imaging of temporomandibular joints. The study was focused on data gathered by direct analysis of occlusion: relationship between the molars (Angle class), horizontal and vertical overlap, preservation of occlusal contacts between the molars (Eichner classification), difference between contact points in maximal intercuspidation and centric position, and contact points on the laterotrusive and mediotrusive side. There was a statistically significant difference in tooth contact in maximal intercuspidation and centric positions between patients and asymptomatic subjects (p < 0.0001). There was also a difference between occlusal contact points on the mediotrusive side (p < 0.05) since the hyperbalanced contacts were only determined in asymptomatic subjects. Study results support the fact that a number of occlusal factors are related to DD. The fact that hyperbalanced contacts were only determined in asymptomatic subjects suggests that their mutual etiopathogenetic correlation is not quite clear.

Oral and Maxillofacial Pathology: Interleukin-1 β, interleukin-6, and tissue inhibitor of metalloproteinase-1 in the synovial fluid of the temporomandibular joint with respect to cartilage destruction

OBJECTIVE

The distribution and biological roles of interleukin (IL)-1 beta, IL-6, and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the synovial fluid of patients with non-inflammatory chronic temporomandibular joint (TMJ) disorders were evaluated in relation to pain upon joint movements and X-ray and magnetic resonance imaging (MRI) findings.

MATERIALS AND METHODS

TMJ aspirates were obtained from 48 patients (48 joints) with chronic TMJ disorders and from 18 controls (18 joints). The IL-1 beta and IL-6 levels in the aspirates were determined by using an enzyme-linked immunosorbent assay and the TIMP-1 level was measured by an enzyme immunoassay. Following examinations for pain upon joint movements and X-ray and MRI observations, the IL-1 beta, IL-6, and TIMP-1 levels and frequencies of their detection were compared.

RESULTS

The IL-1 beta level and frequency of detection showed no correlation with pain upon joint movements or with the X-ray and MRI findings. In the frequency of detection of IL-6, there were significant differences between control (no detection) and all chronic TMJ disorder groups that were classified by imaging diagnosis (P < 0.001). A correlation was also noted between the presence of IL-6 and pain upon joint movements. The IL-6 level was correlated with the TIMP-1 level and with pain upon joint movements. TIMP-1 level was correlated with pain upon joint movements. The TIMP-1 was present in higher level from patients with chronic TMJ disorders who exhibited osseous changes on the X-ray images.

CONCLUSION

The results indicated that the IL-6 and TIMP-1 levels in the TMJ aspirates of patients with chronic TMJ disorders have been raised. The former was not detected in the TMJ aspirates of the control. These findings suggest that IL-6 and TIMP-1 might play a role in the etiology of chronic TMJ disorders, but further studies are needed to validate this.

Rhythmic tongue movements during sleep: A peculiar parasomnia in Costello syndrome

We describe a peculiar parasomnia observed in four Costello infants, characterized by periodic rhythmic movements of the tongue. Ten Costello patients (4 male; age range 9 months to 29 years) underwent 1 full-night laboratory-based video polysomnography. The four youngest patients (2 male and 2 female; age range 9-31 months) presented during sleep repeated stereotyped movements of the tongue, producing a sucking-like or licking-like movement, mostly during non-rapid eye movement (NREM) sleep. Rhythmic tongue movements in Costello syndrome show the features of an NREM sleep parasomnia. Tongue movements during sleep probably originate from brainstem structures and could be facilitated by an impaired control of the oropharyngeal and tongue muscles.

[Role of total systems' connective tissue disease in the development of posttraumatic changes in the temporomandibular joint]

The aim of our work was to ascertain the relationship between temporomandibular joint (TMJ) complications of jaw fractures and displasia of connective tissue (DCT). The results of this investigation suggest, that DCT is an important factor of risk for joint disturbance such as arthritis and osteoarthrosis of TMJ.

Study on the use of temporomandibular joint dysfunction index in temporomandibular disorders

OBJECTIVE

To study the methodological techniques in measuring the severity of temporomandibulr disorders (TMD) and in evaluating the effectiveness of therapies in clinic.

METHODS

Both Fricton's Craniomandibular Index (CMI) and Helkimo's Clinical Dysfunction Index were calculated from 60 TMD patients. Inter-rater reliability was tested to assess the consistency in use between different examiners. Fricton's CMI was used to assess the clinical improvement after accepting a treatment in 21 TMD patients diagnosed as acute disk displacement without reduction.

RESULTS

Correlation Coefficient for inter-rater reliability in two groups was 0.879 and 0.939 respectively for Fricton's CMI and 0.744 and 0.838 for Helkimo Clinical Dysfunction Index. Fricton's TMJ dysfunction index was decreased from 0.337 to 0.021 (P < 0.001) and Fricton's CMI was decreased from 0.185 to 0.011 (P < 0.001) after the treatment in 21 TMD patients with disk displacement without reduction.

CONCLUSIONS

To avoid using subjective and descriptive report in assessment of the severity of TMD and the effectiveness of therapies, Fricton's CMI is recommended as an objective criteria which is simple in clinical use, and ease in scoring.

[Steroidogenesis disorders in women with temporomandibular dysfunction]

The aim of the study was to trace hormone shifts in women suffering from different manifestation of the TMJ pain dysfunction syndrome. Levels of some blood steroid hormones (oestradiol, progesterone, testosterone, cortisol) were determined in 193 female patients aged 14-70. The object of study was blood serum collected in different menstrual phases. It was found that when pain dysfunction syndrome of the TMJ was accompanied by intact dentition and orthognathic occlusion blood steroid levels demonstrated shifts since puberty. In pain dysfunction syndrome of the TMJ accompanied by occlusal disharmony steroid shifts were first registered an early reproductive age. In patients without pain dysfunction syndrome of the TMJ steroid values remained close to those of healthy control. Shifts in steroid production may be indicative of impaired steroidogenesis in women with pain dysfunction syndrome of the TMJ.

[Dysplasia-dependent abnormalities of the temporomandibular joint]

The purpose of this study was to reveal the relationship between temporomandibular joint (TMJ) dysfunction and dysplasia of connective tissue (DCT). This investigation included 53 (34 female and 19 male) patients with TMJ internal derangement (ID) and 53 controls; 24 patients with marked and 53 patients with mild dysfunction of this joint. The symptoms of DCT (such as scoliosis, general joint hypermorbility) and TMJ ID were revealed. Results of this study prove that DCT is one of etiological factors of TMJ ID. The relationship between type of ID and severity of DCT was revealed.

[Temporomandibular joint pain: radiological diagnosis]

Pain in the temporomandibular joint is often the result of internal derangement, other causes are traumatic, functional or inflammatory processes. Conventional radiography is indicated in case of suspected trauma or for specialised preoperative measurements to plan the treatment of various facial dysplasias. MRI and CT should be used in the context with the results of clinical investigation and of axiography to differentiate the various functional and morphological abnormalities of this joint.

Chiropractic care of a patient with temporomandibular disorder and atlas subluxation

OBJECTIVE

To describe the chiropractic care of a patient with cervical subluxation and complaints associated with temporomandibular disorder.

CLINICAL FEATURES

A 41-year-old woman had bilateral ear pain, tinnitus, vertigo, altered or decreased hearing acuity, and headaches. She had a history of ear infections, which had been treated with prescription antibiotics. Her complaints were attributed to a diagnosis of temporomandibular joint syndrome and had been treated unsuccessfully by a medical doctor and dentist.

INTERVENTION AND OUTCOME

High-velocity, low-amplitude adjustments (ie, Gonstead technique) were applied to findings of atlas subluxation. The patient's symptoms improved and eventually resolved after 9 visits.

CONCLUSION

The chiropractic care of a patient with temporomandibular disorder, headaches, and subluxation is described. Clinical issues relevant to the care of patients with this disorder are also discussed.

[RMI of dysfunctional temporomandibular joint (TMJ). Value of gradient-echo T1 sequences in the evaluation of bony structures]

PURPOSE

To identify and classify the different types of bony changes of the condyles in patients with disorders of the temporomandibular joint (TMJ).

MATERIALS AND METHODS

Since 1993, we have imaged over 600 patients with 0.5T MR unit by using gradient-echo T1-weighted sequences in the sagittal and coronal planes.

RESULTS

We will first describe the appearance of the normal TMJ. Then, we will introduce the concept of "Condylo-diskal disunion" using a three grade classification system. We will then describe three patterns of condylar changes: adaptive remodeling, either anterior or more frequently posterior, degenerative lesions with subchondral sclerosis, erosive lesions due to synovial hyperplasia.

CONCLUSION

Using a 0.5T MR unit, a GRE T1 sequence is useful to identify lesions of the disk and detect bony changes. In addition, the tissues posterior to the disk can also be assessed on postcontrast images.

Visco-supplementation therapy in internal derangement of temporomandibular joint

OBJECTIVE

To study if visco-supplementation therapy is useful to the internal derangement (ID) of temporomandibular joint (TMJ).

METHODS

Sixty-three ID cases (69 TMJs) were studied by visco-supplementation therapy. The upper and/or lower articular cavities were irrigated with 5 ml normal saline and injected 0.3-1.0 ml 1% hyaluronate (HA) into articular cavity. If the symptoms of the disease still existed one week later, the therapy should be repeated for 1-2 times, once a week. The control group cases were injected 1 ml 2% lidocaine instead of HA. 8 other TMJs of 6 ID cases and 2 normal cadavers were studied with scanning electron microscopy (SEM) and light microscopy (LM).

RESULTS

The visco-supplement therapy was useful to ID patients. The difference between the test group and control group had statistical significance (chi 2 = 6.6535, P < 0.01). SEM and LM showed that the condyle, disc and bilaminar region in ID were degenerated or destroyed.

CONCLUSIONS

The friction between the articular surfaces in ID was increased and the bilaminar region could not retract the disc as in healthy TMJ. The visco-supplementation therapy can decrease the friction and resume the normal rheology of the diseased TMJs.

Tomographic stability of condyle fossa relationships in 40 treated temporomandibular disorder patients

STATEMENT OF PROBLEM

Condylar position and stability after treatment of 40 temporomandibular disorder patients was studied.

PURPOSE

This study determined pretreatment position and posttreatment condylar stability.

MATERIAL AND METHODS

Forty temporomandibular disorder patients with symptoms of muscles of mastication pain, temporomandibular joint sounds, attrition, interceptive occlusal contacts, and restricted range of motion were used. Axial corrected midcut sagittal tomograms were made of the 80 temporomandibular joints before treatment. Tracings from the tomograms were used to measure and analyze pretreatment position and posttreatment stability.

RESULTS

Pretreatment condyle fossa position was not concentric in 26 of 80 patients (32.5%). Posttreatment condylar position showed no change and was statistically stable.

CONCLUSION

In this study of 40 temporomandibular disorder patients, no statistical change in condylar position was detected. Variable condylar positions were found in the 80 pretreatment axial corrected midcut sagittal tomograms. All patients were asymptomatic after 1 year.

Basicranial flexion, facial reduction and temporomandibular joint dysfunction

Although dysfunction is the major condition affecting the bilateral temporomandibular joint (TMJ), it has defied previous attempts to explain, predict, or prevent its clinical manifestations. A hypothesis is developed that there is an anatomical predisposition to TMJ dysfunction which should be sought in the phylogenetic flexing of the hominid basicranium. It is argued that the glenoid fossa, caught between an ever-increasing brain size and more ventrally oriented facial apparatus, has become deepened and hence labile to dysfunction.

[Post-traumatic temporomandibular pain dysfunction syndrome and the problems raised by its imputation]

Direct, certain and total imputability of trauma as the cause of mandibular joint dysfunction is often difficult to establish. The theoretically obligatory conditions are rarely met, making the expert's opinion quite difficult to establish. The complexity of the pathophysiology involved in mandibular joint dysfunction confirms however the reality of this sequella. By determining the precise lesional or functional origin of the syndrome and the latent or patent nature of the prior status it is possible to ascertain intermediary situations.

[Oto-mandibular ligaments: disco-mallear and malleo-mandibular ligaments]

Phylogenesis, embryology and anatomy are emphasizing that two ligaments are found between the temporo-mandibular joint and the middle ear. These two oto-mandibular ligaments are named the disco-mallear ligament and the malleo-mandibular ligament. Originating from the first arch, these ligaments are not involved in the otologic manifestations of the temporo-mandibular joint syndrome. The disco-mallear ligament is a brake applied to the anterior excursion of the disc. When this disco-mallear ligament is stretched the disc can be displaced anteriorly breeding disc displacement, hypermobility and temporo-mandibular dislocation. The malleo-mandibular ligament is a remainder of the Meckel's cartilage: its role is not clear. When excessive forces are applying on the mandible, ossicles dislocation can be seen the forces being transmitted through it.

The aetiology of temporomandibular disorders: a philosophical overview

Over the last 50 years many theories have been put forward to explain the syndrome currently called 'temporomandibular disorders'. However, it is doubtful whether any single theory fits all the complex features of this condition. The 'multifactorial' explanation also appears flawed. On the assumption that a valid theory should fit the whole evidence, this paper starts by separating the 'predisposing' from the 'initiating' factors, and notes that most existing theories appear to identify the former rather than the latter. The research material is examined in an effort to formulate a theory that is both logical and fits all the known clinical findings.

[The inhibitory effect of hydroprednisolone on tumor necrosis factor in rabbits' temporomandibular joint disturbance syndrome]

In order to study the mechanism of hydroprednisolone for temporomandibular joint disturbance syndrome (TMJDS), 12 white rabbits were injected TNF into the rabbits' right TMJDS for 2 to 3 times, 90,000 u each time, then another drug, 2 mg hydroprednisolone, was injected into these TMJDS again. The rabbits were killed after 8 to 18 days and the TMJDS were examined by microscope. We found the articular tissues only destroyed slightly and sometimes the cartilages were nearly normal. So, the study suggested that hydroprednisolone can reduce the destruction of TNF on rabbit's TMJ obviously. This may be the cause why hydroprednisolone is useful to TMJDS.

Influence of complete denture renewal on craniomandibular disorders: a 1-year follow-up study

Great individual variation in the signs and symptoms of craniomandibular disorders (CMD) and in the adaptability of the masticatory system is evident among complete denture wearers. The masticatory system of 64 edentulous patients (41 women, 23 men; mean age 59 years, range 41-80 years), who came to the Institute of Dentistry for renewal of their complete dentures, was examined before prosthetic treatment and after a 1-year follow-up period. The degree of CMD was assessed using the anamnestic and clinical dysfunction indices of Helkimo. The results show that few complete denture wearers had severe signs and symptoms of CMD. No statistically significant correlation was noted between CMD and either the duration of edentulousness or the number of sets of dentures.

Anterior mandibular repositioning in a patient with temporomandibular disorders: a clinical and tomographic follow-up case report

A 42 year old female with temporomandibular disorders (TMD) was treated by anterior mandibular repositioning which was followed-up clinically and tomographically. The authors tomographically reconfirmed the mandibular repositioning and discovered a type of condyle remodeling which they had not seen previously. Although clinical signs and symptoms of TMD were removed and the condyle was centered tomographically by the anterior repositioning, the MRI image indicated the disk was displaced anteriorly and laterally. The results suggest that image analysis of temporomandibular joint (TMJ) is beneficial and careful application of the treatment for anterior repositioning is recommended.

[Mandibular mechanics in temporomandibular joint pain-dysfunction syndrome]

There are several reasons for perturbed mandibular mechanics in SADAM: craniofacial architecture anomalies, malocclusions, lingual dyspraxia, postural disorders. SADAM diagnosis and therapeutics should be conducted by a pluridisciplinary team.

[Disturbance syndrome of temporomandibular joint in cleft lip and palate patients with crossbite]

The function of temporor-mandibular joint in unilateral cleft lip and palate (UCLP) palients with crossibite was studied in this paper. 29 UCLP patients with crossbite were examined clinically and with Mandibular Kinesiography and X-ray. The results were as bellow (1) Insidence of TMJDS in UCLP patients with crossbite was 75.8%. (2) The condyle of 17.8% patients moved distally and 35.7% of patients moved distally asymmetry. (3) The distance of mandibular border movements in cleft patients were in normal range. We conclude that insidence of TMJDS in UCLP patients were high and we should take it into consideration in the orthodontic treatment.

[Radiographic findings in osteoarthrosis of temporomandibular joint in relation to its pathologic changes]

We analysed the results of the central standard lateral tomographic findings and the macroscopic/microscopic observations on the middle portion of the autopsy materials of 84 temporomandibular joints. It was not suitable to differentiate remodeling and osteoarthrosis of the temporomandibular joint only by whether the surface articular zone of the articular cartilage is intact or not. The early changes of osteoarthrosis could occur in the interface of the bone-cartilage except occuring in the articular zone, even though the surface articular zone was intact. Therefore, we suggest that the definition of osteoarthrosis should be wider. Histopathologic observations proved that the definte radiographic signs, such as sclerosis, erosion, pseudocyst, osteophyte and so on showed on the lateral tomographs were credible signs in the diagnosis of osteoarthrosis.

Signs and symptoms of temporomandibular disorder (TMD) and craniofacial form

Signs and symptoms attributed to temporomandibular disorder (TMD) were registered in 170 persons at an average age of 12.5 years. One hundred and ten were reexamined at an average age of 26.4 years. Craniofacial form was defined on standardized lateral cephalograms, taken at the time points mentioned, by 22 linear and 8 angular measurements. The symptoms, clicking and pain, never appeared to be associated with craniofacial form. The signs, clicking and crepitation, in children did not appear to be associated with craniofacial form either. However, adults with signs were characterized by horizontal facial deficiencies. Adults with clicking joints had a saggitally shorter maxilla and mandibular diagonal, whereas adults with crepitating joints had, in addition, a shorter anterior and posterior cranial base and pharynx. This sagittal "shortness" could already be demonstrated for many of the reported dimensions at the corresponding cephalograms taken about the age of 12.5 years, and did not appear to have changed much over time. It is concluded that the reported TMD signs in adults were associated with a sagittal shorter midface. Part of the typical structure associated with signs antedated the actual detection of these signs by 14 years. This implies that not all TMD signs in adults can be regarded as the exclusive result of some etiologic factor operating after the teenage period. This finding of an association cannot be interpreted as a causal relationship.

Temporomandibular arthropathy: correlation between clinical signs and symptoms and arthroscopic findings

The clinical signs and symptoms of temporomandibular arthropathy were correlated with arthroscopic features of temporomandibular joint disease in 200 consecutive patients. The diagnostic accuracy of the selected clinical signs and symptoms was also tested with arthroscopy as the standard, and sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) were calculated. Pronounced osteoarthrosis was more frequently associated with joint crepitus (P < 0.001). Adhesions were more frequently associated with reduced maximum protrusion (P < 0.001). Crepitation was the only clinical sign that showed acceptable values for SE, SP, PPV, and NPV, and only in diagnosing advanced osteoarthrosis. The values for mild osteoarthrosis were low.

Morphology of the mandibular fossa and the articular eminence in temporomandibular joints with anterior disk displacement

The depth, length, and depth:length ratio of the mandibular fossa, and the angles of the posterior slope of the articular eminence were measured for 91 temporomandibular joints (TMJ) with anterior disk displacement (ADD) in 79 female patients with TMJ dysfunction. As a control, 48 joints in 24 females without TMJ dysfunction were similarly measured. One of the angeles of the posterior slope of the articular eminence was larger for joints with ADD than for the controls (P < 0.01, Student's t-test). There were no other statistically significant differences between the two groups. Among the 91 joints with ADD, there was no statistically significant difference in any variable between joints with ADD with reduction (n = 46) and those with ADD without reduction (n = 45); likewise, there was no association between the magnitude of angle of the posterior slope of the articular eminence and overjet, overbite, canine relationship, or molar relationship.

Craniomandibular stiffness in myogenous and arthrogenous CMD patients, and control subjects: a clinical and experimental investigation

The purpose of this study was to compare active maximum mouth opening, endfeel distance, and craniomandibular stiffness values of three craniomandibular disorder (CMD) patient subgroups and a control group. The CMD patient subgroups consisted of myogenous pain patients and arthrogenous pain patients with a 'closed lock' and arthrogenous pain patients without a 'closed lock'. Both myogenous pain patients and the 'closed lock' patients showed great differences on all parameters (P < 0.05-P < 0.001). However, the arthrogenous pain patients without a 'closed lock' revealed no statistical differences with the control group on any of the tested parameters.

MRI evidence of high signal intensity and temporomandibular arthralgia and relating pain. Does the high signal correlate to the pain?

In order to investigate the relationship between various temporomandibular joint (TMJ) pain levels and the detection of high signal intensity (joint effusion) on T2 weighted magnetic resonance imaging (MRI), 19 consecutive patients who complained of unilateral painful TMJ hypomobility (closed locking) were involved in this study. All patients were clinically examined in a routine manner, and all patients rated their pain levels by a visual analogue scale and eight pain questionnaire prior MRI study. T1 and T2 weighted MRI was taken in sagittal section at unilateral affected joint side. The presence or absence of a high signal intensity spot within the TMJ compartment were judged by three examiners. The high signal intensity was detected in 10 joints, but not in 9 joints. In between these two groups, the pain ratio was calculated and compared. The data showed that there was no significant statistical correlation between pain levels and the presence of high signals. This study disclosed that the MRI detection of high signal intensity in the closed locking TMJ did not directly relate to the presence of TMJ pain nor the increased pain level. These indicate the need of further larger studies.

Computerized three-dimensional magnetic resonance imaging reconstructions of temporomandibular joints for both a model and patients with temporomandibular pain dysfunction

The aim of this study was to assess computerized three-dimensional reconstruction of magnetic resonance images generated of a temporomandibular joint model and the temporomandibular joints of five patients with varying degrees of temporomandibular joint pain and dysfunction. The three-dimensional image reconstruction of an artificial temporomandibular joint model, consisting of a human dried skull and synthetic disk, was used to test the accuracy and reproducibility of the three-dimensional technique. It was found that computerized three-dimensional reconstruction improved the display format of magnetic resonance imaging by enabling multiple two-dimensional images in shades of grey to be viewed as one three-dimensional image with anatomic structures colored as desired. Further, by rotating this image, the anatomic relationships of the temporomandibular joint could be seen from any viewpoint. Volume measurements showed accuracy and reproducibility by independent operators. Computerized three-dimensional reconstruction was applied to the magnetic resonance images obtained from patients. They were used to assess magnetic resonance imaging technique and its applications for interpreting the clinical findings. Disk position, as revealed by the three-dimensional images, was found to correspond with the clinical assessment, except in two instances when the original, right-sided, magnetic resonance imaging was unclear. Three-dimensional reconstruction was simple to apply, required no patient involvement, and made multiple magnetic resonance images easier to interpret.

Presence of neuroreceptors in normal and diseased temporo-mandibular joints

An immunohistochemical study was performed on the articular disk and periarticular tissues of the temporo-mandibular joint (TMJ) in order to ascertain the presence of neuroreceptors (NRec) in these sites. The study was carried out with the APAAP technique on tissue samples obtained from 10 subjects without known TMJ disease and from 5 patients with severe TMJ arthritis or arthrosis. The antibodies used were directed against the following antigens: Gliofibrillary Acidic Protein (GFAP), Leu-7, Myelin Basic Protein (MBP), Neurofilaments 68 kD (NF), Neuron Specific Enolase (NSE), S-100 protein (S-100) and Synaptophysin (SYN). This study revealed that Ruffini's-like, Pacini's-like and Golgi's-like receptors can be demonstrated in TMJ periarticular tissues and that free nervous endings are present in the subsynovial but not within the articular disk. In the latter, elongated cytoplasmic processes of chondrocytes demonstrated strong S-100 immunoreactivity but they were unreactive with all other antibodies. These cytoplasmic processes were more abundant and thicker in the samples obtained from patients with diseased TMJ. The results of this study confirm that different NRec are detectable in TMJ periarticular tissues but they are absent within the articular disk. In the latter site, only chondrocytic processes are evident, especially in diseased TMJ, and they might have been confused with nervous endings in previous morphological studies. Nevertheless the absence of immunoreactivity for NF, NSE and SYN proves that they are not of neural origin.

[Evaluation of the condylar position in the diagnosis of temporomandibular joint dysfunction syndrome]

26 cases with Temporomandibular Joint Dysfunction Syndrome (TMJDS) were included in the present study. Fully corrected lateral tomogrames of TMJ in the intercuspid position were taken for all the cases; and fully corrected lateral arthrotomogrames were taken for 19 cases (21 joints) of them. The area and linear measurements of the joint space were made with the aid of computer. The results showed that the position of the condyle in the patients with TMJDS was located in the posterior position of the fossa. Statistics results showed that there was significant difference between the patient group and control group. Although the posterior displacement of the condyle was often associated with the anterior displacement of the disc, it was not always agreement with the anterior disc displacement. So, the exact diagnosis of disc displacement should be still on the basis of arthrography or other examinations, such as CT or MRI.

Structural and ultrastructural studies of the synovial membrane in temporomandibular joint disturbance syndrome

To gain further knowledge on temporomandibular joint disturbance syndrome (TMJDS), the synovial membranes of 7 patients and 3 cadavers were examined with light microscope and transmission electron microscope. The results showed that the synoviocytes degenerated or disappeared in TMJDS. The cytoplasm contained numerous fibrils, while the organelles diminished in number. The surface of the synovial membrane was covered with a fibrinoid material. The surface of the synovial membrane was covered with a fibrinoid material. The authors consider that these pathological changes reduce or eliminate the normal functions of the synovial membrane, which may lead to damage to the articular cartilage. The articular adhesion found sometimes in TMJDS may be related to the changes in the synovial membrane.

Effects of splint therapy in TMJ dysfunction: a study using magnetic resonance imaging

This pilot study was undertaken to correlate clinical and MRI diagnoses in seven symptomatic TMJ dysfunction patients and to account, if possible, for the clinical improvement in the signs and symptoms after the use of a maxillary stabilizing splint. The symptomatic TMJs were evaluated by means of MRI prior to splint insertion. Sagittal open/closed, and coronal closed images were obtained with a 0.3 T Fonar MR Scanner. A follow-up MRI was taken after three months of splint therapy for the purposes of a comparative study. All subjects responded positively even at the early phase of splint treatment. By the end of the three month period, six subjects experienced full remission of pain in the TMJ and associated masticatory muscles with one subject experiencing only partial remission following therapy. Baseline MRI study revealed that only three subjects had anterior disc displacement while the other four subjects had normal disc/condyle relationships and morphology. In the follow-up MRI study, there were no signs of recapture of the three anteriorly displaced discs despite there being evidence of improved jaw movement and remission of pain symptoms. The use of MRI in this preliminary study indicates that some but not all TMJ pain dysfunction syndromes are caused by internal derangements of the joint. A larger MRI study using the same clinical parameters is indicated for future research.

Tumoral calcinosis of the temporomandibular joint: CT and MR findings

In this article, the CT, three-dimensional CT, and MR findings are reviewed in a 59-year-old woman with tumoral calcinosis involving the temporomandibular joint.

[Operative and pathological observations on secondary synovitis of temporomandibular joint dysfunction syndrome]

14 cases (16 joints) with temporomandibular joint dysfunction syndrome (TMJDS) were included in the present study. All the patients had severe pain of the joint for a long time and the conventional therapy was not effective. The operative and pathological findings of the 14 cases showed that synovitis secondary to microtrauma of the joint really existed and might be one of the reasons causing the severe pain of the joint in some patients with TMJDS.

A three-dimensional finite element model of the mandible including the TMJ and its application to stress analysis in the TMJ during clenching

The purpose of this study was to develop a three-dimensional finite element model of the mandible including the temporomandibular joint (TMJ) and further to investigate stress distributions in the TMJ during clenching. The model consisted of 2088 nodes and 1105 elements, comprising cortical and cancellous bones, articular disc, articular cartilage layer and periodontal ligament. For loading condition, a resultant force of 500 N derived from the cross-sectional areas of the muscles was applied to the model. Compressive stresses were induced in the anterior, middle and lateral areas of the TMJ during clenching, whereas the tensile stresses were induced in the posterior and medial areas. The mean principal stresses on the surface of condyle were -1.642, -0.543, 0.664, -1.017, 0.521 MPa in the anterior, middle, posterior, lateral and medial areas, respectively. The mean stresses on the surface of glenoid fossa were approximately 1/5 to 4/5 those on the surface of condyle, although the patterns of stress distributions were almost similar. In both the articular disc and cartilage layer, the stress distributions were very approximate in qualitative and quantitative aspects. Thus, it is shown that stresses during clenching vary substantially in different structures and areas of the TMJ and that the stresses are reduced by the articular disc and cartilage layer in comparison with actual biting forces exerted by the masticatory muscles, if anatomic relation between various TMJ components is well maintained.

The influence of time, facial side, and location on pain-pressure thresholds in chronic myogenous temporomandibular disorder

This study examined masseter and temporalis pain-pressure thresholds in 29 patients with chronic bilateral myogenous temporomandibular disorder and in 11 controls. Patients with evidence of temporomandibular joint pathosis were omitted. The influence of time, facial side, muscle site, and side of greatest spontaneous pain on pain-pressure thresholds was measured. No significant pain-pressure threshold differences were found between the more and less painful sides, as indicated by the patients, which lends support to theories of centrally mediated pain. Mean pain-pressure thresholds in patients differed over the four sessions, which is consistent with recent reports of fluctuating levels of pain in patients with temporomandibular disorders. Additional findings included significant pain-pressure threshold differences among muscle sites in patients and controls, and lower patient pain-pressure thresholds relative to controls. Within- and between-session reliability was adequate for patients (r = .85 and r = .75, respectively) and controls (r = .90 and r = .75, respectively).