Temporomandibular Disorders Subjects Research Articles

Additional effect of occlusal splints on the improvement of psychological aspects in temporomandibular disorder subjects: A randomized controlled trial

ObjectiveTo measure the effect of occlusal splints as an additional treatment on psychological aspects in temporomandibular disorder patients. DesignA randomized controlled trial was performed comprising 60 adults diagnosed with masticatory myofascial pain according the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The participants were divided equally into 2 treatment groups, which received only counselling (Group 1) or occlusal splints in addition to counselling (Group 2). The assessments occurred at baseline and at 2 and 5 months after treatment. The outcomes were symptoms of anxiety and depression, as well as pain catastrophizing. Two-way ANOVA, Friedman and Mann–Whitney tests were used to perform the statistical analysis, considering a significance level of 5%. ResultsIn relation to the baseline assessment, 60% of the subjects had at least mild anxiety and 25% had at least mild depression, and the mean and standard deviation (SD) of pain catastrophizing was 2.41 (1.33) for Group 1 and 2.06 (1.04) for Group 2. Comparisons between baseline and the fifth-month evaluation showed an improvement in anxiety and depression symptoms only in Group 2 (p<0.05). Otherwise, there was a significant reduction in pain catastrophizing in both groups (p<0.05), with a mean (SD) of 1.14 (1.28) for Group 1 and 0.76 (0.82) for Group 2. ConclusionMinimally invasive strategies could provide an improvement in the psychological aspects of temporomandibular disorder patients, and the use of an occlusal splint seems to hasten the manifestation of these effects.

The role of occlusal factors on the occurrence of temporomandibular disorders

Aims:The aim of this study was to investigate the relationship between occlusal factors and temporomandibular disorders (TMD).Methodology:One hundred patients were selected among those who sought medical or dental care in public practice in Recife, Brazil. The presence of malocclusions and absence of five or more posterior teeth were evaluated by the clinical exam. TMD diagnosis was given using Research Diagnostic Criteria (RDC/TMD). Statistics were carried out using Fisher and Mann–Whitney methods with 5% significance level, as well as multiple logistic regression analysis.Results:The sample was mainly comprised of women (83%), individuals over 30 years old (57%) and singles (53%). The percentage of TMD and malocclusion in total sample was 42% and 50%, respectively, while in TMD subjects, malocclusion was present in 38·1%. There was no association between TMD and the occlusal factors studied.Conclusion:It can be concluded that malocclusion and loss of five or more posterior teeth does not contribute to TMD.

Global Body Posture and Plantar Pressure Distribution in Individuals With and Without Temporomandibular Disorder: A Preliminary Study

ObjectiveThe aim of this study was to evaluate body posture and the distribution of plantar pressure at physiologic rest of the mandible and during maximal intercuspal positions in subjects with and without temporomandibular disorder (TMD). MethodsFifty-one subjects were assessed by the Diagnostic Criteria for Research on Temporomandibular Disorders and divided into a symptomatic group (21) and an asymptomatic group (30). Postural analysis for both groups was conducted using photogrammetry (SAPo version 0.68; University of São Paulo, São Paulo, Brazil). The distribution of plantar pressures was evaluated by means of baropodometry (Footwork software), at physiologic rest and maximal intercuspal positions. ResultsOf 18 angular measurements, 3 (17%) were statistically different between the groups in photogrammetric evaluation. The symptomatic group showed more pronounced cervical distance (P = .0002), valgus of the right calcaneus (P = .0122), and lower pelvic tilt (P = .0124). The baropodometry results showed the TMD subjects presented significantly higher rearfoot and lower forefoot distribution than those in the asymptomatic group. No differences were verified in maximal intercuspal position in the between-group analysis and between the 2 mandibular positions in the within-group analysis. ConclusionsSubjects with and without TMD presented with global body posture misalignment. Postural changes were more pronounced in the subjects with TMD. In addition, symptomatic subjects presented with abnormal plantar pressure distribution, suggesting that TMD may have an influence on the postural system.

Impaired orofacial motor functions on chronic temporomandibular disorders

Because temporomandibular disorders (TMDs) rehabilitation continues to be a challenge, a more comprehensive picture of the orofacial functions in patients with chronic pain is required. This study assessed the orofacial functions, including surface electromyography (EMG) of dynamic rhythmic activities, in patients with moderate-severe signs and symptoms of chronic TMD. It was hypothesized that orofacial motor control differs between patients with moderate-severe chronic TMD and healthy subjects. Seventy-six subjects (46 with TMD and 30 control) answered questionnaires of severity of TMD and chewing difficulties. Orofacial functions and EMG during chewing were assessed.Standardized EMG indices were obtained by quantitative analysis of the differential EMG signals of the paired masseter and temporal muscles, and used to describe muscular action during chewing.TMD patients showed significant greater difficulty in chewing; worse orofacial scores; longer time for free mastication; a less accurate recruitment of the muscles on the working and balancing sides, reduced symmetrical mastication index (SMI) and increased standardized activity during EMG test than healthy subjects. SMI, TMD severity and orofacial myofunctional scores were correlated (P<0.01). Impaired orofacial functions and increased activity of the muscles of balancing sides during unilateral chewing characterized the altered orofacial motor control in patients with moderate-severe chronic TMD. Implications for rehabilitation are discussed.

Mastigação e deglutição em mulheres jovens com desordem temporomandibular

To evaluate chewing and swallowing functions in women with and without temporomandibular disorder (TMD) and investigate the position of the mandible and the hyoid bone as they are important structures in the development of these functions. Seventy women were evaluated in relation to TMD diagnosis according to the Research Diagnostic Criteria, among them, 34 composed the study group (SG) with TMD and 36 took part in the control group (CG). Evaluation of the masticatory and swallowing functions was performed according to the Protocol of Orofacial Myofunctional Evaluation with Scores. Mandibular and hyoid bone position variables were measured by cephalometric analysis. TMD subjects showed a significant difference on tongue (p=0.03) and lip (p=0.04) posture during swallowing function, and a more frequent adoption of a chronic unilateral chewing pattern as well (p=0.03). Moreover, they presented a lower position of the hyoid bone in relation to the mandible (p=0,00). TMD presence resulted on a higher frequency of myofunctional alterations during masticatory and swallowing functions. A greater distance from hyoid bone to the mandible in addition with the presence of painful symptom can justify, partly, the atypical behaviors of the tongue and lips observed on TMD group. The TMD repercussion on alimentaires functions in a young age group justifies the importance of an earlier diagnosis and therapeutic intervention in these individuals.

Multisystem Dysregulation in Painful Temporomandibular Disorders

Multiple physiological and psychological regulatory domains may contribute to the pathophysiology of pain in temporomandibular disorder (TMD) and other bodily pain conditions. The purpose of this study was to evaluate the relationship between multisystem dysregulation and the presence of TMD pain, as well as the presence of different numbers of comorbid pain conditions in TMD. Secondary data analysis was conducted in 131 non-TMD (without comorbid pain) controls, 14 TMD subjects without comorbid pain, 78 TMD subjects with 1 comorbid pain, and 67 TMD subjects with multiple comorbid pain conditions who participated in a TMD genetic study. Twenty markers from sensory, autonomic, inflammatory, and psychological domains were evaluated. The results revealed that 1) overall dysregulation in multiple system domains (OR [odds ratio] = 1.6, 95% confidence interval [CI] = 1.4–1.8), particularly in the sensory (OR = 1.9, 95% CI = 1.3–2.9) and the psychological (OR = 2.1, 95% CI = 2.1–2.7) domains, were associated with increased likelihood of being a painful TMD case; and 2) dysregulations in individual system domains were selectively associated with the increased odds of being a TMD case with different levels of comorbid persistent pain conditions. These outcomes indicate that heterogeneous multisystem dysregulations may exist in painful TMD subgroups, and multidimensional physiological and psychological assessments can provide important information regarding pathophysiology, diagnosis, and management of pain in TMD patients. PerspectiveThe concurrent assessment of multiple physiological and psychological systems is critical to our understanding of the pathophysiological processes that contribute to painful TMD and associated comorbid conditions, which will ultimately guide and inform appropriate treatment strategies that address the multisystem dysregulation associated with complex and common persistent pain conditions.

Trigeminal Nerve Anatomy in Neuropathic and Non-neuropathic Orofacial Pain Patients

Trigeminal neuralgia, painful trigeminal neuropathy, and painful temporomandibular disorders (TMDs) are chronic orofacial pain conditions that are thought to have fundamentally different etiologies. Trigeminal neuralgia and neuropathy are thought to arise from damage to or pressure on the trigeminal nerve, whereas TMD results primarily from peripheral nociceptor activation. This study sought to assess the volume and microstructure of the trigeminal nerve in these 3 conditions. In 9 neuralgia, 18 neuropathy, 20 TMD, and 26 healthy controls, the trigeminal root entry zone was selected on high-resolution T1-weighted magnetic resonance images and the volume (mm3) calculated. Additionally, using diffusion-tensor images (DTIs), the mean diffusivity and fractional anisotropy values of the trigeminal nerve root were calculated. Trigeminal neuralgia patients displayed a significant (47%) decrease in nerve volume but no change in DTI values. Conversely, trigeminal neuropathy subjects displayed a significant (40%) increase in nerve volume but again no change in DTI values. In contrast, TMD subjects displayed no change in volume or DTI values. The data suggest that the changes occurring within the trigeminal nerve are not uniform in all orofacial pain conditions. These structural and volume changes may have implications in diagnosis and management of different forms of chronic orofacial pain. PerspectiveThis study reveals that neuropathic orofacial pain conditions are associated with changes in trigeminal nerve volume, whereas non-neuropathic orofacial pain is not associated with any change in nerve volume.

Relationship Between Temporomandibular Disorders, Widespread Palpation Tenderness, and Multiple Pain Conditions: A Case-Control Study

The multiple bodily pain conditions in temporomandibular disorders (TMD) have been associated with generalized alterations in pain processing. The purpose of this study was to examine the relationship between the presence of widespread body palpation tenderness (WPT) and the likelihood of multiple comorbid pain conditions in TMD patients and controls. This case-control study was conducted in 76 TMD subjects with WPT, 83 TMD subjects without WPT, and 181 non-TMD matched control subjects. The study population was also characterized for clinical pain, experimental pain sensitivity, and related psychological phenotypes. Results showed that: 1) TMD subjects reported an average of 1.7 comorbid pain conditions compared to .3 reported by the control subjects (P < .001); 2) Compared to control subjects, the odds ratio (OR) for multiple comorbid pain conditions is higher for TMD subjects with WPT [OR 8.4 (95% CI 3.1–22.8) for TMD with WPT versus OR 3.3 (95% CI 1.3–8.4) for TMD without WPT]; 3) TMD subjects with WPT presented with reduced pressure pain thresholds (PPTs) in both cranial and extracranial regions compared to TMD subjects without WPT; and 4) TMD subjects with WPT reported increased somatic symptoms. These findings suggest that pain assessment outside of the orofacial region may prove valuable for the classification, diagnosis, and management of TMD patients. PerspectiveTMD subjects with WPT experience a greater level of multiple comorbid pain conditions, compared to TMD subjects without WPT and non-TMD controls. Integration of bodily pain assessments can be informative for evaluation, diagnosis, and management of TMD.

Dysregulation of the Autonomous Nervous System in Patients with Temporomandibular Disorder: A Pupillometric Study

The role of the autonomic nervous system (ANS) was recently investigated in Temporomandibular disorders (TMD). Several authors argue that in subjects with TMD there is a dysregulation of ANS. Recent literature support that Pupillometry is a simple non-invasive tool to study ANS. The aim of this study was to investigate the relationship between TMD and ANS activity using pupillometry recording in Infrared light at rest Mandible Position (RP); Infrared light at Forced Habitual Occlusion (FHO); Yellow-green light at RP; Yellow-green light at FHO. Forty female subjects were enrolled: 20 case patients showed TMD based on the Research Diagnostic Criteria for TMD, and 20 control patients, aged matched, had no signs or symptoms of TMD. Statistical analysis was performed on average pupil size. Ratio between pupil size in FHO and RP (FHO/RP ratio) and yellow-green and infrared (light/darkness ratio) lighting were carried out. Within group differences of pupil size and of “ratio” were analyzed using a paired t test, while differences of pupil size between groups were tested using an unpaired t test. Statistical comparisons between groups showed no significant differences of absolute values of pupil dimension in RP and FHO, both in yellow-green and in infrared lighting. In addition, there were no significant differences within groups comparing RP and FHO in yellow-green light. In within group comparison of pupil size, differences between RP and FHO were significant in infrared conditions. Control subjects increased, whereas TMD patients decreased pupil size at FHO in infrared lightening. FHO/RP ratio in darkness and light/darkness ratio in RP were significantly different between groups. Taken together, these data suggest that TMD subjects have an impairment of the sympathetic-adrenergic component of the ANS to be activated under stress. The present study provides preliminary pupillometric data confirming that adrenergic function is dysregulated in patients with TMD.

Validity of the ‘protocol of oro‐facial myofunctional evaluation with scores’ for young and adult subjects

The aims of this study were to analyse the validity, sensitivity and specificity of the protocol of oro-facial myofunctional evaluation with scores (OMES) for oro-facial myofunctional disorder (OMD) diagnosis in young and adult subjects. Eighty subjects were examined. The OMES was validated against the Nordic orofacial test-screening (NOT-S) protocol (criterion validity) (Spearman correlation test). The construct validity was tested by analysis of the ability of the OMES (i) to differentiate healthy subjects (n = 22) from temporomandibular disorder (TMD) patients (n = 22), which frequently have OMD (Mann-Whitney test) and (ii) to measure the changes that occurred in a subgroup with TMD between the period before and after oro-facial myofunctional therapy (T group, n = 15) (Wilcoxon test). Two speech therapists trained with the OMES participated as examiners (E). There was a statistically significant correlation between the OMES and NOT-S protocols, which was negative because the two scales are inverse (r = -0·86, P < 0·01). There was a significant difference between the healthy and TMD subjects regarding the oro-facial myofunctional status (OMES total score, P = 0·003). After therapy, the T group showed improvement in the oro-facial myofunctional status (OMES total score, P = 0·001). Inter- and intra-examiner agreement was moderate, and the reliability coefficients ranged from good to excellent. The OMES protocol presented mean sensitivity and specificity = 0·80, positive predictive value = 0·76 and negative predictive value = 0·84. The OMES protocol is valid and reliable for clinical evaluation of young and adult subjects, among them patients with TMD.

Occlusal risk factors associated with temporomandibular disorders in young adults with normal occlusions

The aim of this study was to characterize occlusal stability in young adults with temporomandibular disorder (TMD). Thirty-one patients (aged 19-31 years) with complete natural dentition and Angle class I occlusion who exhibited TMD were compared with 31 age- and sex-matched healthy control subjects. The occlusal registrations were performed using the T-Scan II occlusal imaging and analysis system. Center of occlusal force, asymmetry index of occlusal force, maximal movement of COF, premature contacts, clusion time, and disclusion time were recorded. Compared with control subjects, TMD subjects had a significantly higher frequency of premature contacts (16/32, 50.0%) and greater bilateral asymmetry in the occlusal force. Furthermore, prolonged clusion time and disclusion time also were observed in TMD subjects. These results suggest that a significant association exists between occlusal stability and TMD in young adults.

Myoelectric manifestations of jaw elevator muscle fatigue and recovery in healthy and TMD subjects

The effects of muscle pain and fatigue on the control of jaw elevator muscles are not well known. Furthermore, the myoelectric manifestations of fatigue and recovery from fatigue in the masticatory muscles are not reported in literature. The main aims of this study were (i) to evaluate the possible use of surface electromyography (sEMG) as an objective measure of fatigue of the jaw elevator muscles, (ii) to compare the myoelectric manifestations of fatigue in the temporalis anterior and masseter muscles bilaterally, (iii) to assess recovery of the investigated muscles after an endurance test and (iv) to compare fatigue and recovery of the jaw elevator muscles in healthy subjects and patients with muscle-related temporomandibular disorders (TMD). The study was performed on twenty healthy volunteers and eighteen patients with muscle-related TMD. An intra-oral compressive-force sensor was used to measure the voluntary contraction forces close to the intercuspal position and to provide visual feedback of submaximal forces to the subject. Surface EMG signals were recorded with linear electrode arrays during isometric contractions at 20%, 40%, 60% and 80% of the maximum voluntary contraction force, during an endurance test and during the recovery phase. The results showed that (i) the slope of the mean power spectral frequency (MNF) and the initial average rectified value (ARV) could be used to monitor fatigue of the jaw elevators, (ii) the temporalis anterior and masseter muscle show the same myoelectric manifestations of fatigue and recovery and (iii) the initial values of MNF and ARV were lower in patients with muscle-related TMD. The assessment of myoelectric manifestations of fatigue in the masticatory muscles may assist in the clinical assessment of TMDs.

Maximum voluntary clenching and unilateral chewing in patients with mild-moderate TMD

Temporomandibular disorders (TMD) consist of a number of clinical problems that involve the masticatory muscles, the temporomandibular joint and associated structures. The aim of the study was to quantitatively compare electromyographic (EMG) parameters of patients with mild-moderate TMD and healthy subjects. Twenty patients with mild-moderate TMD (5 men, 15 women, 22–56 y) and 19 healthy subjects (9 men, 10 women, 21–49 y) were analyzed. sEMG of the left and right masseter and temporalis anterior muscles was recorded using a wireless device (TMJoint, BTS, Italy). Each subject performed a 5 s-maximum voluntary contraction (MVC) with the teeth in intercuspal position (CLENCH), and one with two 10 mm-thick cotton rolls positioned on the mandibular second premolars/first molars (COT). EMG activity was further recorded during unilateral, right and left, gum chewing. EMG potentials of both MVC and chewing were standardized as percentages of the potentials obtained during COT recording [1]. During MVC, EMG activities were less symmetric and had a larger torque component in TMD patients than in healthy subjects (muscular asymmetry: 10.4±9.1% vs 4.4±4.2%, Student’s t-test, p=0.013; torque: 9.8±10.9% vs 4.4±4.0%, p=0.047). During chewing, all healthy subjects had a good coordination between masseter and temporalis contractions, with a prevalent activity of the working-side muscles. Among TMD patients, instead, 9 subjects performed at least one of their unilateral chewing tests with an altered muscular coordination. EMG activity of TMD patients was less coordinated than that of healthy subjects, with a larger variability between chewing cycles (Hotelling’s ellipse area: 2275±2734% vs 1010±845%, Student’s t-test, p=0.061). sEMG analysis could be a useful tool to detect functionally altered stomatognathic muscular coordination. Dote ricerca: FSE, Regione Lombardia

Different Pain, Different Brain: Thalamic Anatomy in Neuropathic and Non-Neuropathic Chronic Pain Syndromes

Trigeminal neuropathic pain (TNP) and temporomandibular disorders (TMD) are thought to have fundamentally different etiologies. It has been proposed that TNP arises through damage to, or pressure on, somatosensory afferents in the trigeminal nerve, whereas TMD results primarily from peripheral nociceptor activation. Because some reports suggest that neuropathic pain is associated with changes in brain anatomy, it is possible that TNP is maintained by changes in higher brain structures, whereas TMD is not. The aim of this investigation is to determine whether changes in regional brain anatomy and biochemistry occur in both conditions. Twenty-one TNP subjects, 20 TMD subjects, and 36 healthy controls were recruited. Voxel-based morphometry of T1-weighted anatomical images revealed no significant regional gray matter volume change in TMD patients. In contrast, gray matter volume of TNP patients was reduced in the primary somatosensory cortex, anterior insula, putamen, nucleus accumbens, and the thalamus, whereas gray matter volume was increased in the posterior insula. The thalamic volume decrease was only seen in the TNP patients classified as having trigeminal neuropathy but not those with trigeminal neuralgia. Furthermore, in trigeminal neuropathy patients, magnetic resonance spectroscopy revealed a significant reduction in the N-acetylaspartate/creatine ratio, a biochemical marker of neural viability, in the region of thalamic volume loss. The data suggest that the pathogenesis underlying neuropathic and non-neuropathic pain conditions are fundamentally different and that neuropathic pain conditions that result from peripheral injuries may be generated and/or maintained by structural changes in regions such as the thalamus.

Reduced endurance of the cervical flexor muscles in patients with concurrent temporomandibular disorders and neck disability

Subjects with temporomandibular disorders (TMDs) have been found to have clinical signs and symptoms of cervical dysfunction. Although many studies have investigated the relationship between the cervical spine and TMD, no study has evaluated the endurance capacity of the cervical muscles in patients with TMD. Thus the objective of this study was to determine whether patients with TMD had a reduced endurance of the cervical flexor muscles at any level of muscular contraction when compared with healthy subjects. One hundred and forty-nine participants provided data for this study (49 subjects were healthy, 54 had myogenous TMD, and 46 had mixed TMD). There was a significant difference in holding time at 25% MVC between subjects with mixed TMD when compared to subjects with myogenous TMD and healthy subjects. This implies that subjects with mixed TMD had less endurance capacity at a lower level of contraction (25% MVC) than healthy subjects and subjects with myogenous TMD. No significant associations between neck disability, jaw disability, clinical variables and neck flexor endurance test were found.

Cortical processing of facial tactile stimuli in temporomandibular disorder as revealed by magnetoencephalography

We used magnetoencephalography (MEG) to investigate the cortical processing of an innocuous facial tactile stimulus in healthy subjects and in a group of subjects suffering from chronic temporomandibular disorder (TMD). Equivalent current dipoles (ECDs) were extracted for a time period of 1 s following stimulus application, and their location, duration and onset time determined. The counts of ECDs extracted did not differ significantly between the two groups. In contrast, we found statistically significant differences in ECD duration and onset time. Specifically, ECD duration was longer in the TMD group in the precentral gyrus, and ECD onset time was earlier in the parietal operculum. In addition, we found differences in the internal organization and clustering of the brain areas involved indicating a less tight association and a less coordinated stimulus information processing in the TMD group. Altogether, these results show that an innocuous facial tactile stimulus is differently processed in the brain of TMD subjects, when compared to controls, reflecting altered brain mechanisms due to chronic pain.

Postural loads during walking after an imbalance of occlusion created with unilateral cotton rolls

BackgroundIt was showed that stomatognathic functions correlate with alterations in locomotion, that are detectable through the analysis of loading during walking. For example, subjects with symptoms of Temporomandibular disorders (TMDs) showed a significant higher load pressure on the two feet, respect to health subjects, when cotton rolls were inserted. This previous study appeared to suggest that the alteration of postural loads associated to a particular alteration of stomatognathic condition (in this case, the cotton rolls inserted between the two dental arches) is detectable only in TMD's subjects, while it resulted not detectable in health subjects, because in that study, health subjects did not show any significant alteration of postural loads related to the different stomatognathic tested conditions. In other words, in that previous study, in the group of health subjects, no significant difference in postural loads was observed among the different test conditions; while TMD subjects showed a significant higher load pressure on the two feet when cotton rolls were inserted, respect to all the other tested conditions. Thus, the aim of this study was to better investigate these correlations in health subjects without TMD's symptoms, testing other different intra-oral conditions, and to verifywhether an experimentally induced imbalance of occlusion, obtained putting an unilateral cotton roll, could cause an alteration of postural loading on feet during walking.FindingsIn a sample of thirty Caucasian adult females (mean age 28.5 ± 4.5), asymptomatic for TMDs, when a cotton roll was positioned on the left or the right sides of dental arches, so causing a lateral shift of the mandible, the percentage of loading and the loading surface of the ipsi-lateral foot, left or right, were found to be significantly lower than in habitual occlusion (p < 0.05). Males were not included because of their different postural attitude respect to females. Further studies in a sample of males will be presented.ConclusionsThis study showed that in health subjects without TMD's symptoms, an experimentally induced imbalance of the occlusion, obtained through an unilateral cotton roll, is associated to detectable alterations in the distribution of loading on feet surface, during walking.

Magnetic resonance imaging on TMJ disc thickness in TMD patients: A pilot study

Studies of temporomandibular joint (TMJ) discs removed from autopsy specimens and in surgery indicate that they are often thicker in patients with temporomandibular disorders (TMDs). Disc thickness may also change when the condyle moves in and out of the joint fossa during opening and closing. The purpose of this pilot study was to test the hypothesis that the TMJ disc thickness is greater in TMD patients than in healthy subjects and is affected by the degree of jaw opening. Magnetic resonance images (MRI) were made of the TMJs in young volunteers, 9 asymptomatic subjects and 9 TMD subjects, at closed and at 10-, 20-, and 30-mm open positions. The thickness of the anterior and posterior bands of the discs and the intermediate zones was measured and compared between TMD and control groups, and between closed and opened positions, using the repeated-measures method in general linear model (alpha=.05). The hypothesis that the disc was thicker in the TMD than in the control group was supported with respect to the anterior band and intermediate zone (P<.046), but not with respect to the posterior band. The hypothesis that the thickness is affected by the degree of jaw opening was only supported for the posterior band, where it increased during opening in both groups (P<.005). The results indicate that the anterior band and the intermediate zone of the TMJ discs are thicker in TMD patients than in healthy subjects. The posterior band thickness increases with mouth opening in both asymptomatic and TMD subjects.

Temporomandibular Disorder and New Aural Symptoms

To report the prevalence and demographics of temporomandibular disorder (TMD) within a population of clinic patients and to describe the prevalence of revisited and new, previously unstudied, aural symptoms described by a sample of these patients with TMD (hereinafter "TMD patients"). A retrospective evaluation of patient records was completed to determine the percentage and the demographics of TMD patients in a clinical setting. A prospective analysis was done on the self-reported prevalence of previously studied and new aural symptoms of 78 TMD study patients compared with 78 control patients without TMD. A private otolaryngology practice in a rural Arizona town. Patients with TMD and aural symptoms. Ten percent of all new otolaryngology clinic patients were diagnosed as having TMD. Of the 78 patients, 27 (35%) listed the ear as one of their sites of pain. The prevalence of each of the 8 aural symptoms assessed was significantly higher in TMD patients compared with controls (P < .001). A warm and/or fluid sensation in the ear and a stuffed cotton sensation in the ear were the most indicative symptoms of TMD because they had the highest relative risk ratios in TMD patients. Aural symptoms of loud noise sensitivity and cold air/wind sensitivity are also relevant and were approximately 5 times more frequent in TMD subjects than in controls. Patients with TMD are a significant component of otolaryngology practice. There are previously uninvestigated aural symptoms that occur much more frequently in TMD patients than in patients without TMD.

Maximal bite force and its association with temporomandibular disorders

Individuals with temporomandibular disorders (TMD) are expected to have decreased maximum bite forces (MBF). This way, this study compared the MBF in subjects with TMD to a control group and also evaluated its association with age, gender, height and weight. Forty healthy adults with complete natural dentition divided into four groups according to gender and presence or absence of TMD signs/symptoms (based on the Research Diagnostic Criteria RDC) underwent a MBF test with a gnathodynamometer in molar and incisal areas. Statistical analysis was performed by ANOVA and Student-Newman-Keuls test (p=0.05), and the relationship between age, gender, weight, height and MBF was verified by Pearson's correlation test. There were no differences in MBF results between TMD and control groups (p>0.05). Female subjects exhibited lower MBF than male and MBF for the anterior area was lower than that for posterior area (p<0.05). Significant correlation was found between MBF and weight in TMD subjects (p<0.05), except for the anterior area in female subjects. There was a positive correlation between MBF and height in TMD male subjects (p<0.05). Within the limitations of this study, it is possible to conclude that bite force was not affected by TMD. Correlation between MBF and weight in TMD subjects and between MBF and height in TMD male subjects was observed.