A quantitative computer-assisted analysis of disc displacement in patients with internal derangement using sagittal view magnetic resonance imaging

Temporomandibular joint anchorage surgery: a 5-year follow-up study

The purpose of this study was to confirm the 5-year efficiency of temporomandibular joint (TMJ) anchorage, using clinical evaluation and magnetic resonance imaging (MRI). We also studied the influence of disc length and position on efficiency and postoperative condylar height. Sixty-one patients (76 joints) undergoing TMJ disc anchorage were followed up for >5 years. Visual analogue scale (VAS) score and maximum mouth-opening pre-and postsurgery were analysed and patient satisfaction recorded. Disc length, condyle height and disc position pre- and postsurgery were measured using MRI. Patients were ranked as A, B or C degree according to postoperative disc condyle position. Mean follow-up time was 71.34 months. Maximum mouth-opening improved by 14.34 ± 5.87 mm, and VAS score decreased by 33.44 ± 20.56 (P < 0.05). Clinical evaluation efficiency was 84.21%; patient satisfaction rate was 85.53%. On follow-up MRI, 68 joints were judged A or B degree (89.67%). Disc length was 7.96 ± 1.38 mm, 7.10 ± 1.41 mm and 5.75 ± 1.16 mm in A, B and C groups, respectively. In patients evaluated as C, condylar height decreased by 0.43 ± 1.36 mm, while increasing by 0.67 ± 1.88 mm and 0.51 ± 1.09 mm in A and B groups, respectively (all P < 0.05). We concluded that anchorage surgery improves mouth-opening and eliminates pain, longer disc length is related to better postoperative disc position, and significant condylar reconstruction occurs after disc repositioning. MRI confirmed that TMJ disc anchorage is reliable 5 years postsurgery.

Temporomandibular Disorders and Headache

Temporomandibular disorders (TMD) and primary headaches can be perpetual and debilitating musculoskeletal and neurological disorders. The presence of both can affect up to one-sixth of the population at any one time. Initially, TMDs were thought to be predominantly musculoskeletal disorders, and migraine was thought to be solely a cerebrovascular disorder. The further understanding of their pathophysiology has helped to clarify their clinical presentation. This article focuses on the role of the trigeminal system in associating TMD and migraine. By discussing recent descriptions of prevalence, diagnosis, and treatment of headache and TMD, we will further elucidate this relationship.

Prevalence of temporomandibular disorders in fibromyalgia and failed back syndrome patients: a blinded prospective comparison study

OBJECTIVES

The objective of this study was to determine the prevalence of temporomandibular disorders (TMD) and evaluate psychosocial domains in patients with fibromyalgia (FM) compared with patients with failed back syndrome (FBS).

STUDY DESIGN

The study included 51 (32 FM and 19 FBS) adult patients who were administered orofacial pain and psychological questionnaires before a clinical examination. Presence of TMD was diagnosed according to the Research Diagnostic Criteria for TMD.

RESULTS

Fifty-three percent of the FM patients reported having face pain compared with 11% of the FBS patients. Of those FM patients who reported face pain, 71% fulfilled the criteria for a diagnosable TMD. FM patients had significantly higher subscale scores for somatization, obsessive-compulsive, medication used for sleep, and fatigue compared with FBS patients. Eighty-seven percent of the FM patients reported a stressful event and 42.3% had symptoms indicating posttraumatic stress disorder.

CONCLUSION

The high prevalence of TMD and psychosocial dysfunction among FM patients suggests wide-reaching dysregulation of autonomic and hypothalamic-pituitary-adrenal axis functions.

Temporomandibular disorders and other causes of facial pain

Temporomandibular disorders and facial pain cause significant discomfort and disability for affected patients. Understanding the clinical presentation, pathogenesis, and therapy is essential in helping patients who have these problems. This article critically reviews these aspects, with an emphasis on their relationship to headache.

Temporomandibular disorders and headache

Headache is a common symptom, but when severe, it may be extremely disabling. It is assumed that patients who present to dentists with headache often are diagnosed with a temporomandibular disorder (TMD), although many may have migraine. TMD as a collective term may include several clinical entities, including myogenous and arthrogenous components. Because headache and TMD are so common they may be integrated or separate entities. Nevertheless, the temporomandibular joint (TMJ) and associated orofacial structures should be considered as triggering or perpetuating factors for migraine. This article discusses the relationship between the TMJ, muscles, or other orofacial structures and headache.

Sensitivity and specificity of a new MRI method evaluating temporo-mandibular joint disc–condyle relationships: an in vivo study

The aim of this study was to evaluate sensitivity and specificity of a new method to locate temporo-mandibular joint (TMJ) disc using magnetic resonance imaging (MRI) and analyze disc-condyle relationships, in asymptomatic subjects and patients with disc displacement. Twenty-nine sagittal MRI of 16 subjects, 8 asymptomatic volunteers and 8 subjects with anterior disc displacement, were carried out during controlled opening from intercuspal position up to a 25 mm opening. Selected sections were analyzed with a graphic computerized system of coordinates. The total surface area (TS) of disc section was separated into anterior surface area (AS) and posterior surface area. Areas were determined by computer. Two trained examiners drew images at random. The reliability of AS/TS ratio index was evaluated in a previous study. AS/TS ratio sensitivity (Se) and specificity (Sp) were calculated closed mouth, 5 mm open and 25 mm open mouth. Best sensitivity (Se=0.63) and specificity (Sp=0.81) were obtained when MRI was realized with closed mouth and 25 mm open mouth. Lower sensitivity was observed when MRI was performed either with closed mouth (Se=0.54) or 25 mm open mouth (Se=0.18). Lower specificity was observed with 5 mm open mouth (Sp=0.68). In conclusion, it was confirmed as well that MRI of anterior disc displacement should be performed with closed mouth and opened mouth. Thus, further studies are required to assess disc displacement and mechanical alterations and to evaluate the risk of direct damage on TMJ tissues.

Proposed graphical system of evaluating disc–condyle displacements of the temporomandibular joint in MRI

The aim of this preliminary study was to standardize the reading of magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). The MRI was conducted on a control group of eight subjects. In this study, the analysis of joint relationships was limited to the oblique sagittal plane, during the movement of controlled opening. The sections were analyzed by a computer-assisted quantitative method of graphical evaluation. The total surface area (TS) of the disc section was divided into an anterior surface area (AS) and a posterior area (PA), in accordance with a line joining the center of the condyle (C) to the center of the articular tubercle of the temporal bone (T). The disc-condyle relationships in the chosen plane of section were evaluated by the AS/TS ratio. If TS remains relatively constant, the AS/TS values on average decrease from 0.5 to 0.3 between the closed mouth position and the 25 mm open position. The results show good intra-observer reproducibility (p=0.26), evaluated by Wilcoxon's test. In conclusion, this protocol enables the displacement of the disc-condyle assembly during mouth opening to be described. Observed on a larger sample, the AS/TS would be able to show a range of variability in functional disc positions.

The relationship between temporomandibular joint disc morphology and stress angulation in skeletal Class III patients

The aim of this study was to examine the relationship between disc position and stress direction on the condyle by means of stress analysis using the rigid body spring model (RBSM) theory. The material consisted of 88 joints of 44 Class III dentofacial deformity patients, divided into symmetry and asymmetry groups on the basis of the Mx-Md midline position. The asymmetry group was identified by comparison with a reference midline vertical plane passing through a plane from ANS to Me. Asymmetry was diagnosed when the angle between these two planes was greater than 3 degrees. The geometry of the stress analysis model was based on sagittal tomography of the subject. The first molar, gonial angle, and the most anterior, superior, and posterior points on the condyle were plotted on a computer display, and stress angulation on the condyles was calculated with the RBSM program. In addition to anterior displacement with or without reduction, three types of disc position could be identified using magnetic resonance imaging (MRI): anterior, fully covered and posterior. In the asymmetric group, stress angulation was significantly higher (P < 0.05) at the deviation side compared with the non-deviation side. There was also a significant correlation between disc position and stress angulation (P < 0.05). In the asymmetry group, regression analysis indicated a significant correlation (P < 0.001) between the difference in stress angulation (between the deviation side and the non-deviation side) and the degree of asymmetry (measured by the angle of asymmetry). This study demonstrated that temporomandibular joint (TMJ) stress was associated with TMJ morphology in Class III patients whether or not they were asymmetric.

Evaluation of disc position in edentulous patients with complete dentures

OBJECTIVE

This study evaluated the condyle-disc relationship on magnetic resonance image (MRI) in a group of subjects with silent temporomandibular joints (TMJs) when tested clinically with those in subjects with discernible temporomandibular sounds. Study design Twenty-five completely edentulous patients were selected to participate in this study. The study was based on bilateral MRIs of 15 patients (with articular sound) and 10 symptom-free volunteers (control).

RESULTS

It was noted that disc displacement was found in 45% of the TMJs with no history of articular sounds. In 6 TMJs of control group, a reducing disc displacement was found, and in 3 TMJs a permanent displacement was found. Disc displacements were identified in 70% of patients. Reducing disc displacement was found in 19 of these TMJs, whereas permanent displacement was found in 2 TMJs. In 9 of the joints of the symptomatic group, a superior disc position was found. Also verified was a significant association between reducing disc displacement and biconvex disc.

CONCLUSION

These observations demonstrated that internal derangements can not be associated to clicking joints or symptoms of temporomandibular disorders in elderly edentulous patients, and the presence of displaced discs seems to be associated to altered disc morphology, but not to osseous abnormalities.

A clinical comparison of internal joint disorders in patients presenting disk-attachment pain: prevalence, characterization, and severity of bruxing behavior

This study clinically documents the presence of disk-attachment pain (DAP) related to the severity of bruxism and to the prevalence of internal joint disorders in patients and controls. The sample consisted of 394 temporomandibular disorder (TMD) and bruxing behavior patients and 104 nonbruxer control subjects. The TMD group was subdivided in a group of 109 disk-attachment pain patients and 285 bruxing behavior-nonDAP groups. The second reference group was a sample of 104 nonbruxing behavior subjects. Comprehensive evaluations (including history of signs and symptoms), use of questionnaires, clinical examination, palpation of muscles and joints, classification of bruxing behavior by the degree of severity, and diagnostic tests were performed in patients and controls. There was a prevalence of disk-attachment pain in the group of TMD and bruxing behavior patients. The degree of jaw opening was lower in the DAP group as compared to the TMD/bruxism-nonDAP group and controls. The mean Visual Analog Scale (VAS) value for the joint pain complaints was slightly elevated in the DAP group as compared to the TMD/bruxism-nonDAP group. Specific masticatory disorders including difficulties to open, pain on opening, chewing pain, fatigue on chewing, jaw deviation to opening, and change to a soft diet, were significantly more prevalent in the DAP group as compared to the other reference groups. Our conclusions are based upon a review of the literature and on the results of this study: a. DAP is a relatively well defined stage of internal joint derangement (IJD); and b. compared to other groups, DAP patients as a subgroup are relatively more impaired by their masticatory and other functional disorders. This study provides strong support to other studies and demonstrates that DAP is a well-differentiated and severe internal joint disorder.

Disk position and the bilaminar zone of the temporomandibular joint in asymptomatic young individuals by magnetic resonance imaging

OBJECTIVE

The purpose was to study the disk position of the temporomandibular joint (TMJ) in young individuals without any clinical signs or symptoms or history of internal derangement or degenerative joint disease and to study the features of the bilaminar zone of the TMJ in sagittal magnetic resonance (MR) images and the behavior of the bilaminar zone during jaw opening.

STUDY DESIGN

MR imaging examinations of 80 TMJs of 40 symptom-free healthy subjects (20 women and 20 men) with a mean age of 26.9 years formed the basis of this study.

RESULTS

In 33 of the 40 symptom-free subjects (82.5%), there was a normal relationship between disk and condyle at occlusion, whereas 5 individuals had unilateral disk displacement and 2 had bilateral disk displacement. The superior part of the bilaminar zone could be identified in all of the 40 symptom-free subjects. The inferior band of the bilaminar zone was identified bilaterally in 57.5% of individuals and unilaterally in 20%. In 9 subjects, the inferior band of the bilaminar zone could not be identified in any of the TMJs.

CONCLUSIONS

Disk displacement of the TMJ occurred in approximately 20% of the young individuals in this sample. The use of both sagittal and oblique coronal MR images is of importance for classification of the position of the disk in that the oblique coronal imaging plane rendered significant complementary information to that of the sagittal images. The identification of both the superior and the posterior band of the bilaminar zone must be considered new information. The superior band remained consistently in contact with the fossa at the open-mouth position.

Multifactorial analysis of differences in temporomandibular joint hard tissue anatomic relationships between disk displacement with and without reduction in women

STATEMENT OF PROBLEM

Without multifactorial models, it is difficult to resolve whether hard tissue tomographic relationships can distinguish differences between temporomandibular joint (TMJ) internal derangement diagnoses.

PURPOSE

The purpose of this study was to use multifactorial models to examine whether there are hard tissue anatomic and orthopedic characteristics that distinguish temporomandibular joints with disk displacement with reduction from disk displacement without reduction.

MATERIAL AND METHOD

. TMJ tomograms from female patients who had unilateral disk displacement diagnosed with (n = 84) or without (n = 78) reduction were compared with the use of 14 linear and angular measurements and 8 ratios. A representative classification tree model was tested for fit with sensitivity, specificity, accuracy, and likelihood accountability, and the results were compared with a multiple stepwise logistic regression model and univariate analysis.

RESULTS

Disk displacement without reduction joints had longer mean postglenoid fossa heights (P<.0005), greater mean fossa depth (P<.017), and narrower mean absolute superior joint spaces (P<.041) than disk displacement with reduction joints (univariate t test). The classification tree had 4 terminal nodes; to differentiate the joints, it used the eminence radius and the absolute superior joint space to anterior joint space ratio subordinate to the postglenoid process height. The tree model accounted for 31.4% of the likelihood (Rescaled Cox and Snell R(2)) with 73.5% accuracy (sensitivity 82.6% and specificity 65.4%). Disk displacement without reduction joints had either deeper posterior fossa walls or posterior walls of average length combined with a superior-to-anterior joint space ratio of less than 0.83; this suggests a more open-wedge-shaped anterior joint space combined with a less-rounded articular eminence. In contrast, most disk displacement with reduction joints had shorter posterior fossa wall height combined with more equal or larger superior-to-anterior joint spaces. The logistic regression model was less accurate than the classification tree model (sensitivity 60.9%, specificity 66.7%) and accounted for only 9.9% of the likelihood (Rescaled Cox and Snell R(2)) and 63.6% accuracy. The postglenoid process height was the strongest differentiating factor in all models.

CONCLUSION

Hard tissue relationships revealed by central tomogram sections were able to model notable differences between disk displacement with and without reduction joints when examined as contingency-based multifactorial systems.

Temporomandibular disorders: a review of current understanding

OBJECTIVE

The purpose of this article is to conduct a narrative review of current evidence regarding the understanding, evaluation, management, and treatment of temporomandibular disorders to provide a broad perspective and updated introduction to an important and controversial subject with rapidly changing developments and limited well-designed research.

DATA SOURCES

Studies were identified through a search of MEDLINE for 3 topics (temporomandibular disorder, temporomandibular joint, and chronic pain) over a 10-year period (January 1988 to August 1998) and of bibliographies of identified studies and review articles.

STUDY SELECTION

More than 5000 articles were produced. In-depth review of all of this literature was beyond the scope of the present article, which is intended to provide an overview. The amount and diversity of the literature and the limitations of covering such a broad topic being recognized, the papers selected were those that reviewed limited topics or studied focused areas. This report is not a systematic (qualitative) or meta-analysis (quantitative) review. An acknowledged limitation of this narrative review method lies in the potential for bias in selection. The referenced works do not include all papers reviewed; only pertinent literature and reviews with comprehensive references were selectively included.

CONCLUSIONS

Advances in basic and clinical science have resulted in important changes in the understanding and management of temporomandibular disorders. Many treatments are not supported by research, and the role of dentistry is changing to a more diagnostic and management-based model from the hands-on treatment procedures of the past. The present science-based understand-ing of a biopsychosocial disorder is important in properly and responsibly dealing with patients with temporomandibular disorders.

Mandibular articular disk position changes during Herbst treatment: a prospective longitudinal MRI study

The aim of this prospective longitudinal study of 15 consecutively treated Class II malocclusions was to assess any possible changes in the relative position of the articular disk to the condyle during different phases of Herbst therapy. Using a disk position index, parasagittal MRIs (central, medial and lateral slices) of the right and left TMJ were analyzed at five occasions: before Herbst treatment (T1), at start of treatment when the appliance was placed (T2), after 6 weeks of treatment (T3), after 13 weeks of treatment (T4), and after 7 months of treatment when the appliance was removed (T5). In all subjects Herbst treatment resulted in Class I or overcorrected Class I dental arch relationships. Condyle position was on average unchanged during Herbst treatment (T1 to T5). Before treatment (T1) the articular disk was in a slight protrusive position relative to the condyle. At start of treatment (T2) the mandible was advanced to an incisal edge to edge position. Because of the physiologic relative movement of disk and condyle on mandibular protrusion the disk attained a pronounced retrusive position. At the end of treatment (T5), the disk had almost returned to its original pretreatment position. In several cases, however, a slight retrusive disk position prevailed. In conclusion, Herbst treatment did not result in any adverse changes in articular disk position. On the contrary, the Herbst appliance could possibly be useful in the therapy of patients with anterior disk displacement.

Diagnostic value of 4 criteria to interpret temporomandibular joint normal disk position on magnetic resonance images

OBJECTIVE

This study was undertaken to evaluate different criteria to establish normal disk position on magnetic resonance images.

STUDY DESIGN

Magnetic resonance image findings of 137 consecutive patients with temporomandibular disorders and 23 asymptomatic volunteers were used in this study. Three calibrated observers interpreted the images individually. Four closed-mouth and 1 open-mouth criteria were tested for their ability to define normal and abnormal temporomandibular joint disk positions on magnetic resonance images.

RESULTS

For the 46 joints in the asymptomatic volunteers, the criterion that yielded the highest percentage of normal disk position diagnoses was the disk's intermediate zone (93.5%). Clock face criteria produced the following declining percentages of normal disk position diagnoses: 10 o'clock, 82.6%; 11 o'clock, 63.0%; and 12 o'clock, 39.1%. Similar results were obtained for the patients with temporomandibular disorders. In both groups, as the number of normal disk position diagnoses declined, the percentage of joints with a diagnosis of disk displacement with reduction increased. Conversely, the percentage of joints with a diagnosis of disk displacement without reduction (in the group of patients with temporomandibular disorders) did not appear to be substantially affected by the 4 closed-mouth disk position criteria.

CONCLUSIONS

These results suggest that the intermediate zone criterion for disk displacement is the more stringent criterion and the one that would yield the lowest number of false positives when the disk position is being judged in the closed-mouth sagittal view.

Variability of disk position in asymptomatic volunteers and patients with internal derangements of the TMJ

This study determined the variability of temporomandibular joint (TMJ) disk position in medial, central, and lateral aspects of the joint using magnetic resonance imaging (MRI). Subjects had clinical evidence of reciprocal TMJ clicking (N = 123) or restricted mandibular motion (N = 52). Eighty-nine asymptomatic volunteers provided a control group. Disk position was quantified on MRI by measuring the angle formed by a line through the middle of the condyle and perpendicular to the Frankfort plane and a line through the same midpoint of the condyle and tangential to the posterior-most aspect of the disk. The disk position in asymptomatic TMJs varied considerably with a tendency toward farther anterior placement in more lateral images. In 47 TMJs from a total of 52 TMJ5 (90%), restricted mobility was associated with anterior disk displacement (ADD) without reduction. The disk position demonstrated a mean displacement of 77 degrees without significant differences at the medial and lateral aspects of the condyle. One hundred TMJs from a total of 123 TMJs (81%) with reciprocal clicking demonstrated ADD with reduction. Tomograms revealed larger lateral displacements or rotational displacements in these joints, whereas medial images frequently showed similar ranges of disk positions as compared with asymptomatic TMJs. The results suggest that disk positions of up to +15 degrees on medial tomograms and +30 degrees on lateral tomograms should be regarded as normal variations. Furthermore, multisection analysis of all parasagittal images improved the separation between disk displacement and asymptomatic TMJs.