Temporomandibular Disorders Group Research Articles

Vibrotactile amplitude and frequency discrimination in temporomandibular disorders

The purpose of this study was to determine whether the elevation in vibrotactile detection threshold, found in many individuals with temporomandibular disorders (TMD), is paralleled by suprathreshold impairments. Participants with TMD were compared with pain-free control subjects in their ability to discriminate on the basis of differences in amplitude and frequency between vibratory stimuli delivered to the face. The TMD group was significantly impaired with respect to frequency discrimination, but not amplitude discrimination. This dissociation suggests that the cortical processing of vibrotactile signals may be affected in TMD patients. TMD participants' estimates of the intensity of their spontaneous and palpation-evoked pain did not significantly correlate with performance on either discrimination task; this finding makes it unlikely that impaired vibrotaction in TMD is primarily the result of a pain-dependent gating of tactile signals.

The cortisol response to psychological stress in temporomandibular dysfunction

The salivary cortisol response to psychological stress and its relationship to psychological variables was examined in 36 female temporomandibular dysfunction (TMD) sufferers and 39 female control participants. Saliva samples were taken at baseline, after completion of a modified version of the Trier Social Stress Test, and after rest. Participants also completed a battery of measures, including Visual Analog Scales for measuring pain intensity and disability and a number of established psychological scales. The TMD group showed a significantly higher cortisol response to experimental stress than the control group. Closer examination of the data revealed that the TMD group was heterogeneous and composed of a group that hypersecreted cortisol in response to stress (Hi-SC TMD group) and another group whose cortisol response was not significantly different from the control group (Lo-SC TMD group). The Lo-SC TMD group showed significant negative relationships between cortisol response and self-reported symptoms of both anxiety and depression, plus significantly more use of the Praying or Hoping coping strategy on the Coping Strategies Questionnaire. A dual relationship between TMD symptoms and the stress response is proposed. First, a biological predisposition to TMD is suggested by the stress response in the Hi-SC TMD group. Second, both psychological and biological variables appear to be important factors in those TMD patients who respond to stress with low cortisol secretion.

Vibrotactile threshold is elevated in temporomandibular disorders

Experimental pain can elevate vibrotactile threshold, a phenomenon attributed in the literature to the operation of a ‘touch gate.’ It is not known, however, whether clinical pain produces similar effects. To explore this possibility, we measured vibrotactile threshold in patients with temporomandibular disorders (TMD) whose pain had a prominent myalgic component. Two-interval forced-choice tracking was used to determine threshold for a 25-Hz vibratory stimulus presented on the cheek. Threshold was found to be significantly elevated in the TMD group, compared to an age- and gender-matched control group of pain-free individuals. Within the TMD group, those with a supra-median level of muscle tenderness (corrected for background levels of spontaneous pain) had significantly higher threshold than those with lower levels of palpation pain. These findings are consistent with the idea of a touch gate, and suggest the usefulness of further research in this area with clinical pain populations. The effects of an adapting stimulus (25 Hz, 20 dB SL) were also studied, and found to produce parallel elevations in vibrotactile threshold in the TMD and pain-free groups. This result indicates that at least some adaptation occurs at a higher (subsequent) level of somatosensory information processing than does the touch gating implied by the unadapted thresholds.

Systemic ligament hypermobility in temporomandibular disorders

Systemic ligament hypermobility (benign hypermobile joint syndrome or BHJS) and masticatory parafunction (clenching/bruxism) were evaluated in intracapsular TMD (n=110) and non-TMD (n=112) populations. Individuals that had a ligament mobility index greater than four were classified as benign hypermobile joint syndrome (BHJS) utilizing the modified Carter-Wilkinson systemic ligament hypermobility scale. All subjects in the TMD and control groups were female, between the ages of 10 and 79 with Angles' Class I molars and cuspids. This study found Benign Hypermobile Joint Syndrome (BHJS) and masticatory parafunction, when present simultaneously in females, to be significantly associated with intracapsular TMD symptoms (P<0.001).

Otalgia in patients with temporomandibular joint disorders

Otalgia without organic causes is a common symptom in temporomandibular dysfunction (TMD) patients even though the etiology is controversial. Investigations of the influence of TMD treatment on otalgia are scarce. This follow-up study analyzed the clinical profile of TMD patients with otalgia and evaluated the treatment outcome. A total of 400 consecutive TMD patients (75% women) were divided in two groups: group 1 consisted of 233 patients (58%) with no complaint of ear symptoms and group 2 consisted of 167 patients (42%) with complaints of otalgia. The patients were examined with a standardized protocol and treated similarly with conservative methods. Group 2 was referred and examined by otolaryngologists. Otalgia patients (group 2) had statistically significantly higher pain scores ( p 0.02). They belonged to the greater dysfunction scores (Di III) according to the Helkimo Pain and Dysfunction index (41% vs. 24%; p < 0.001). There was a statistically significant association with pain on condyle palpation and otalgia ( p < 0.01). One year after the first examination, the patients exhibited no pain or occasionally mild pain in 66% (group 1) and 74% (group 2) ( p 0.35). Of the otalgia patients, 48% no longer had otalgia and 32% of the patients experienced mild or occasional otalgia. The changes in dysfunction scores after 1 year revealed significant improvement. No difference was found between group 1 and 2 in pain and dysfunction score. For the dysfunction index readings 0 and I,77% and 73% had no or only mild symptoms (Di 0 and I). The conclusions of this study are that TMD patients with otalgia are not a separate TMD group and they responded well to conservative treatment.

Tinnitus, vertigo, and temporomandibular disorders

Although tinnitus and vertigo have been reported as associated with temporomandibular disorders (TMD) for many years, no control studies have been reported. This study was designed to include two large control populations, as well as a large TMD sample. The null hypothesis was tested. The results revealed that tinnitus and vertigo were significantly more prevalent in the TMD group than in either control group. Reasons for the association of TMD and these otologic symptoms have been proposed and they are discussed. Presently the cause is unknown. (A M J O RTHOD D ENTOFAC O RTHOP 1995;107:153-8.)

A multiple logistic regression analysis of the risk and relative odds of temporomandibular disorders as a function of common occlusal features.

A multiple logistic regression analysis was used to compute the odds ratios for 11 common occlusal features for asymptomatic controls (n = 147) vs. five temporomandibular disorder groups: Disc Displacement with Reduction (n = 81), Disc Displacement without Reduction (n = 48), Osteoarthrosis with Disc Displacement History (n = 75), Primary Osteoarthrosis (n = 85), and Myalgia Only (n = 124). Features that did not contribute included: retruded contact position (RCP) to intercuspal position (ICP) occlusal slides < or = 2 mm, slide asymmetry, unilateral RCP contacts, deep overbite, minimal overjet, dental midline discrepancies, < or = 4 missing teeth, and maxillo-mandibular first molar relationship or cross-arch asymmetry. Groupings of a minimum of two to at most five occlusal variables contributed to the TMD patient groups. Significant increases in risk occurred selectively with anterior open bite (p < 0.01), unilateral maxillary lingual crossbite (p < 0.05 to p < 0.01), overjets > 6-7 mm (p < 0.05 to p < 0.01), > or > 5-6 missing posterior teeth (p < 0.05 to p < 0.01), and RCP-ICP slides > 2 mm (p < 0.05 to p < 0.01). While the contribution of occlusion to the disease groups was not zero, most of the variation in each disease population was not explained by occlusal parameters. Thus, occlusion cannot be considered the unique or dominant factor in defining TMD populations. Certain features such as anterior open bite in osteoarthrosis patients were considered to be a consequence of rather than etiological factors for the disorder.

Tinnitus and vertigo in patients with temporomandibular disorder.

The association of tinnitus and vertigo with temporomandibular disorder (TMD) has been debated for many years. The observation that patients with TMD have otologic symptoms is confounded because tinnitus and vertigo are common symptoms in the normal population. The present study was conducted to determine if tinnitus and vertigo are actually more prevalent in patients with TMD than in appropriate age-matched controls. One control group was recruited from patients seeking care for health maintenance and the other from patients seeking routine dental care. We surveyed 1032 patients: 338 had TMD and 694 served as two age-matched control groups. Tinnitus and vertigo symptoms were significantly more prevalent in the TMD group than in either of the control groups. The mechanism of the association of TMD and otologic symptoms is unknown.

An epidemiological study of temporomandibular disorders in university students of Taiwan.

A total of 2033 university students were surveyed for the prevalence of TMD in Taiwan. It was found that 42.9% of the students had one or more signs related to TMD, and females were slightly more frequently found. Clicking of the joint was the most common sign. Occlusal factors such as balancing contact, dental restoration, molar guidance in eccentric movement, etc., were more often found in the TMD group. Scores on stress, general anxiety, emotion and anger were higher in the TMD group while tension, ambition, depression, competition and test anxiety were not as significant. Although the prevalence of TMD in this population is high, the severity and treatment demands are low.

Asymptomatic urinary abnormalities found via the Japanese school screening program: a clinical, morphological and prognostic analysis.

Clinicohistopathologically, we observed 109 patients with asymptomatic urinary abnormalities found via the Japanese school medical screening process. Follow-up was for a mean period of 9.3 +/- 4.0 years. More than 80% of the patients had either IgA nephropathy (IgAN, 47 cases, 43.1%), thin membrane disease (TMD; 21 cases, 19.3%) or normal glomerulus (NG; 20 cases, 18.3%). Complete remission appeared in 60.0% of the NG cases, 14.3% of the TMD cases and in 19.1% of the IgAN cases, and remission was significantly high in the NG group (p less than 0.01). No patient with TMD and NG ever progressed to the extent of pronounced proteinuria or renal failure. One patient deteriorated and required hemodialysis, and 2 patients developed renal insufficiency in IgAN. All of these cases possessed severe glomerular sclerotic change when the initial biopsies were performed. All IgAN cases that went into remission, however, had minor glomerular abnormalities. A positive family history of urinary abnormality was observed in 14.1% of both the IgAN group and the NG group, whereas we observed 71.4% in the TMD group, which was significantly high (p less than 0.01). Other cases included 4 each with non-IgA proliferative glomerulonephritis, focal segmental glomerular sclerosis, membranoproliferative glomerulonephritis and Alport's nephritis. It was concluded that the majority of patients (80.7%) with urinary abnormalities found via the school screening program had IgAN, NG or TMD. 74.5% of the IgAN group and 85.7% of the TMD group had long histories of urinary abnormalities extending into adulthood with no deterioration of the renal function.

Trauma history in diagnostic groups of temporomandibular disorders

Trauma history was studied for association with disease among six diagnostic subgroups of 230 patients with temporomandibular disorder (TMD) from a private practice setting with (1) disk displacement (DD) with reduction, (2) DD without reduction, (3) osteoarthrosis (OA) with prior derangement history, (4) primary OA, (5) myalgia only, and (6) subluxation only. Except for subluxation (29%), trauma history typified TMD patient groups 1 to 5 (63%, 79%, 44%, 53%, 54%) ( p < 0.001) compared with 13% and 18% of asymptomatic ( n = 61) and symptomatic ( n = 161) student control subjects, and 11% of general dental patients ( n = 150). TMD groups 2 and 3 differed significantly ( p < 0.05). The high prevalence of trauma in the myalgia-only group complicates the concept of myofascial pain-dysfunction syndrome as solely a stress or centrally mediated disorder. DD without reduction (43%) and with reduction (38%) had the highest prevalences of motor vehicle accident trauma, myalgia and OA groups had less, and subluxation-only cases had none. On the other hand, patients with DD without reduction were also the only group to report multiple trauma (29%), suggesting that although specific traumatic events may seem to precipitate clinical symptoms, they may not always have initiated the problem. Trauma may be both an important cumulative and precipitating event in TMDs.