Magnetic resonance imaging in the evaluation of temporomandibular joint disc displacement--a review of 144 cases

Automated pediatric TMJ articular disk identification and displacement classification in MRI with machine learning

OBJECTIVE

To evaluate the performance of an automated two-step model interpreting pediatric temporomandibular joint (TMJ) magnetic resonance imaging (MRI) using artificial intelligence (AI). Using deep learning techniques, the model first automatically identifies the disk and the TMJ osseous structures, and then an automated algorithm classifies disk displacement.

MATERIALS AND METHODS

MRI images of the TMJ from 235 pediatric patients (470 joints) were reviewed. TMJ structures were segmented, and the disk position was classified as dislocated or not dislocated. The UNet++ model was trained on MRI images from 135 and tested on images from 100 patients. Disk displacement was then classified by an automated algorithm assessing the location of disk centroid and surfaces for bone landmarks.

RESULTS

The mean age was 14.6 ± 0.1 years (Female: 138/235, 58 %), with 104 of 470 disks (22 %) anteriorly dislocated. UNet++ performed well in segmenting the TMJ anatomical structures, with a Dice coefficient of 0.67 for the disk, 0.91 for the condyle, and a Hausdorff distance of 2.8 mm for the articular eminence. The classification algorithm showed disk displacement classification comparable to human experts, with an AUC of 0.89-0.92 for the distance between the disk center and the eminence-condyle line.

CONCLUSION

A two-step automated model can accurately identify TMJ osseous structures and classify disk dislocation in pediatric TMJ MRI. This tool could assist clinicians who are not MRI experts when assessing pediatric TMJ disorders.

CLINICAL SIGNIFICANCE

Automated software that assists in locating the articular disk and surrounding structures and classifies disk displacement would improve the TMJ-MRI interpretation and the assessment of TMJ disorders in children.

Exercise therapy in postoperative patients with temporomandibular joint internal derangement: A systematic review

OBJECTIVE

Postoperative patients with temporomandibular joint internal derangement (ID) often have problems such as limited mouth opening and pain. Exercise therapy can be advantageous for improving the recovery of patients following surgery. However, there is continuing discussion on the precise aspects of the exercise program, including the optimal timing, length, intensity, and use of assistive equipment. Hence, this study aimed to incorporate pre-existing exercise treatment regimens and investigate their impact.

METHODS

Publications that detailed the clinical treatment of patients with temporomandibular joint ID who received postoperative exercise therapy interventions were included. Nine databases were searched until October 1st, 2023. The JBI critical appraisal tools were used to assess the methodological quality of the included studies.

RESULTS

Five studies were finally included for subsequent analysis; two were randomised controlled studies, and three were quasi-experimental. Exercises suitable for such patients encompass vertical, transverse, and horizontal stretching, among which vertical stretch can be divided into active and passive movements. The start time ranged from the first to the fifth week after surgery, with a duration of 1-6 months. Although the data in the studies could not be integrated and further analysed, preliminary results showed that maximum mouth opening and pain in patients improved significantly. The therapeutic effect of combining three exercise methods was best and was related to patient compliance.

CONCLUSION

Exercise therapy positively affects postoperative rehabilitation in patients with temporomandibular joint ID. It is proposed that targeted, comprehensive studies be conducted to provide a basis for designing more sophisticated exercise therapy regimens and further confirm its curative effect.

Quantitative volume and area assessment of masticatory muscles through magnetic resonance imaging in patients with temporomandibular joint disorders

OBJECTIVE

To compare volume and surface area measurements of the lateral pterygoid (LPM), medial pterygoid (MPM), and masseter muscles (MM) as calculated on magnetic resonance imaging (MRI) based on the position of the temporomandibular joint disk, mouth position, and patient sex, and to calculate the correlations of the measurements among the muscles.

STUDY DESIGN

Measurements of muscle volume and area were performed on the MRIs of 51 patients. Wilcoxon, Kruskal-Wallis, and Mann-Whitney U tests were used to calculate the significance of differences in measurements. The Spearman correlation coefficient calculated the correlation of measurements among the muscles. The significance of difference was established at P < .05.

RESULTS

Volume and area of the left MPM in patients with disk displacement without reduction (DDWOR) were larger than in patients with normal disk position (P ≤ .040). MM volumes were smaller with DDWOR than with DD with reduction bilaterally (P ≤ .031). The volume and area of LPM and MM were significantly different between closed and open mouth positions (P < .001). Differences in volume and area between females and males were significant for all muscles in volume (P ≤ .021) and for MPM and MM in area (P ≤ .021). Significant positive correlations were found among all muscles for volume and area.

CONCLUSION

Volume and area measurements of the masticatory muscles varied according to disk and mouth position and patient sex and exhibited significant positive correlations.

Role of Dynamic 3 Tesla MRI in the Evaluation of Temporomandibular Joint Dysfunction

INTRODUCTION

The internal derangement of the temporomandibular joint (TMJ) is the most common type of dysfunction. Internal derangement can be divided into anterior and posterior disc displacement. Anterior disc displacement is the most common type, which is further classified into anterior disc displacement with reduction (ADDWR) and without reduction (ADDWoR). Temporomandibular joint dysfunction (TMD) symptoms are pain, reduced mouth opening, and joint sound. The main aim of this study was to correlate the clinical findings and magnetic resonance imaging (MRI) diagnosis of TMD in symptomatic and asymptomatic TMJs.

METHODS

This prospective observational study was conducted in a tertiary care hospital on a 3T Philips Achieva MRI machine with 16-array channel coils after obtaining approval from the institutional ethical committee. A total of 60 TMJs of 30 patients were included in the study. After the clinical examination of each patient, an MRI of both right and left TMJs was done. In patients with unilateral TMD, the asymptomatic side was used as the asymptomatic joint, and the affected side as the symptomatic joint. Asymptomatic patients without any symptoms of TMD were used as controls for bilateral TMD cases. MRI with high-resolution specific serial sections was obtained in both open- and closed-mouth positions. A p-value of <0.05 was considered a statistically significant agreement between clinical and MRI diagnoses of internal derangement.

RESULTS

Out of a total of 30 clinically asymptomatic TMJs, only 23 were normal on MRI. On MRI, 26 TMJs showed ADDWR and 11 showed ADDWoR. The most common shape of the disc was biconcave and the displacement was anterior in symptomatic joints. The most common type of articular eminence shape was sigmoid in ADDWR and flattened in ADDWoR. Agreement between clinical and MRI diagnosis in this study was 87.5% (p < 0.001).

CONCLUSION

 The study concluded substantial agreement between clinical and MRI diagnosis of TMJ internal dysfunction and suggests that the diagnosis of the internal dysfunction can be made clinically but the exact position, shape, and type of disc displacement can be assessed precisely with the help of MRI.

Magnetic Resonance Imaging Evaluation of Closed-Mouth TMJ Disc-Condyle Relationship in a Population of Patients Seeking for Temporomandibular Disorders Advice

Objective

To characterize the closed-mouth temporomandibular joint (TMJ) disc-condyle relationship in a population of individuals who sought hospital services for temporomandibular disorders (TMD).

Methods

Two hundred and twenty-four TMJ magnetic resonance images (MRIs) of 112 patients were assessed in all spatial planes to classify disc position with respect to the condyle in a closed-mouth position.

Results

Disc displacement (DD) was present in 62.1% and superior disc position in 29.9% of the patients. Position could not be determined in 8% of the cases. Among DD, pure anteriorized position was the most common condition (34.4%), with different combined translational and rotational displacements in all the other joints (27.7%).

Conclusion

There is a wide biological variability in disc position in closed mouth among patients seeking for TMD advice. Getting deeper into the correlation with clinical symptoms is recommended to refine the potential relevance of any diagnostic and management strategies based on the imaging evaluation of TMJ disc position.

Can dynamic magnetic resonance imaging replace static magnetic resonance sequences in evaluation of temporomandibular joint dysfunction?

Background

Static MRI was used as an effective tool for diagnosis of temporomandibular joint dysfunction instead of invasive techniques such as arthroscopy and arthrography. The purpose of this study was to detect whether dynamic MRI can be used instead of static MRI in diagnosis of TMJ dysfunction or not.

Results

According to disc displacement, anterior disc displacement was detected in 29 joints (36.25%) by both static and dynamic MRIs, and medial and lateral disc displacements were detected only by static MRI. Regarding disc mobility, dynamic MRI detects stuck disc in 4 joints versus 2 joints detected by static MRI (p value 0.008). Condylar translation was abnormal in 18 joints (22.5%) by static MRI and in 26 joints (32.5%) by dynamic MRI (p value < 0.001). The detection rate of articular disc for dynamic MRI was 87.5% versus static MRI 92.5% (p value 0.038), and the detection rate of condylar head for dynamic MRI was 97.5% versus static MRI 100% (p value 0.012).

Conclusion

Dynamic MRI cannot replace static MRI in evaluation of TMJ dysfunction; both of them support each other for accurate diagnosis and better image quality.

Relationship between Clinical Symptoms and Magnetic Resonance Imaging in Temporomandibular Disorder (TMD) Patients Utilizing the Piper MRI Diagnostic System

Clinical problems of the temporomandibular joint (TMJ) and the masticatory musculature are both included in the term temporomandibular disorder (TMD). The purpose of the present study was to examine the pathology of the joints of patients diagnosed with TMD utilizing the dedicated Piper MRI-based classification, and to link these pathologies with various symptoms while considering their severity. In total, 64 patients with clinical TMD were examined. Symptoms were recorded using a questionnaire. The clinical examination included diagnosing the occlusion in centric relation, which was followed by a standardized MRI. It was confirmed that, although they occurred in a high percentage in all classes, muscle pain and occlusal interference are not indicators of TMJ damage. The results indicate that the progressive degradation of the TMJ, represented by qualification to the higher Piper classes, is associated with an increase in TMJ pain only up to a certain stage. For the highest Piper classes, the joint pain occurs in a smaller percentage of patients, but sounds are more frequent.

Outcomes of treatment with genioplasty and temporomandibular joint anchorage surgery

BACKGROUND

Anterior Disc Displacement without Reduction (ADDwoR) in adolescence can result in condylar resorption which produces mandibular retrusion/deviation (MR/D) in adulthood. This study aims to analyze the therapeutic effect of simultaneous genioplasty and temporomandibular joint (TMJ) anchorage surgery on ADDwoR with MR/D patients.

METHODS

During 2016-2018, ADDwoR with MR/D cases were included and underwent TMJ anchorage surgery and genioplasty guided by digital design. Pre-/Post-surgical clinical manifestations, facial photography, radiographic data, facial shape satisfaction of clinicians/patients/third-party were recorded and analyzed.

RESULTS

A total of 32 cases (52 joints) were included. The average age was 24.09. Ratio of male/female was 4/28. Visual analog pain scale (VAS) score pre-/post-surgical ranged from 3 to 9 and 0-3, with an average of 6.03 and 1.18 (p < 0.01). Maximal mouth opening pre-/post-surgical ranged from 16 to 33 mm and 33-40 mm, with an average of 22.43 mm and 36.46 mm (p < 0.01). MRI was completed and showed stable disc reduction without recurrence 1 year postoperatively. MR/D was corrected and a better face shape was obtained. The satisfaction rate of clinicians, patients and third-parties was 92.375%, 94.156% and 94.218%, with an average of 93.583%.

CONCLUSION

For ADDwoR with MR/D patients, simultaneous TMJ anchorage surgery and genioplasty can improve TMJ symptoms/functions, correct facial appearance, and enhance the degree of satisfaction. The postoperative effect is stable, safe and reliable, which is worthy of clinical promotion.

Imaging of the temporomandibular joint

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.

Does clinical findings correlate with magnetic resonance imaging (MRI) findings in patients with temporomandibular joint (TMJ) pain? A cross sectional study

Background

Although magnetic resonance imaging (MRI) helps to clearly visualize the disorders in temporomandibular joint (TMJ), the relationship between cross-sectional and clinical findings has not been precisely established. The aim of this study was to evaluate the relationship between clinical symptoms and MRI findings in individuals with TMJ pain.

Material and Methods

This cross-sectional study, conducted on the clinical and MRI findings of the patients, who applied to Uşak University, Oral and Maxillofacial Surgery Clinic with TMJ pain between the years 2016-2019. The primary predictor variables were MRI findings; disc position (normal, disc displacement with reduction (DDWR), disc displacement without reduction (DDWOR)), disc structural distortion (normal, folded, lengthened, round, biconvex, thick), condyle degeneration type (normal, moderate, severe) and joint effusion (JE) (absent, present). The primary outcome variable was pain, recorded on a visual analog scale (VAS) (numbered between 0-10). The other variables were demographic variables (age/gender). The relationship between clinical and MRI findings were statistically evaluated. The data were analysed by Kruskal Wallis and Mann Whitney U test. Chi-square (x2) test was used for categorical variable comparisons. P values < .05 were considered to indicate statistical significance.

Results

Clinical and MRI records of 700 TMJ, from 350 patients with the mean age of the 31 (12-65) were evaluated in this study. Statistically significant differences were found between; disc position and pain, disc position and JE; JE and pain; disc structural distortion and pain; and disc structural distortion and disc position. JE was seen more common in DDWOR group. The most common disc distortion, seen in patients with JE, is the folded type.

Conclusions

The present study can infer that pain is associated with disc position, JE, disc structural distortion, and DDWOR is associated with JE. Folded type disc is the most common disc type in TMJ with JE.

Key words:Internal derangement, TMJ, MRI evaluation, disc morphology, disc position, condyle degeneration, joint effusion.

Imaging of orofacial pain

BACKGROUND

Orofacial pain is a common complaint, with an estimated 75% of cases caused by dental disease, specifically a diseased pulp. A small percentage of orofacial pain cases will require specialist referral most commonly to oral medicine specialists or oral and maxillofacial surgeons from a dental perspective, or otolaryngologists or neurologists from a medical perspective.

IMAGING MODALITIES

Following a thorough history and clinical examination, imaging is often required to narrow the differential diagnosis or answer a specific query related to the final diagnosis. A range of imaging modalities can be used to evaluate orofacial pain including dental panoramic tomography (DPT), intraoral radiographs, cone beam computed tomography (CBCT), multidetector computed tomography (MDCT), ultrasonography (US), magnetic resonance imaging (MRI) and nuclear medicine.

IMAGING PROTOCOLS

This paper provides a guideline outlining imaging protocols for categories of facial pain divided into: (a) unilateral odontalgia; (b) unilateral facial pain; (c) combined unilateral odontalgia and facial pain; (d) trigeminal neuralgia; (e) trigeminal neuropathic pain with or without other sensory, autonomic or motor features; (f) temporomandibular joint disorders and associated pain; (g) referred pain and (h) non-specific orofacial pain.

CONCLUSION

Imaging for orofacial pain should be tailored to answer a specific query related to the aetiology of the reported pain. This should result in a specific diagnosis or narrowing of the differential diagnosis as possible causes of orofacial pain are eliminated. Choosing the correct imaging modality and protocol based on the pain category is important for efficient and effective pain diagnosis and management.

Does Incidence of Temporomandibular Disc Displacement With and Without Reduction Show Similarity According to MRI Results?

Purpose

The aim of this study is to assess MRI reports of the patients and to provide retrospective analysis by conducting detailed evaluation of temporomandibular disc position.

Patients and Methods

MRI images of 259 patients from 2008 to 2017 were reviewed retrospectively. Existence of disc displacement in joint with and without reduction, existence of effusion in joint gap, arthritis, degenerative changes in joints and limitation of movement of joint and anatomic characteristics were evaluated.

Results

One hundred and seventeen (45.2%) of the patients had healthy joint connection bilaterally. Anterior disc displacement was observed in 101 (38.9%) of the patients. The number of the patients having disc displacement with reduction was 50 (19.3%) and without reduction was 51 (19.6%) similarly.

Conclusion

The incidence of anterior disc displacement with or without reduction was similar; besides this, the majority of the patients diagnosed with anterior disc displacement were unilateral.

Psychological Factors that Influence Decision-Making Regarding Trauma-Related Pain in Adolescents with Temporomandibular Disorder

We evaluated the clinical, magnetic resonance imaging (MRI), and psychological characteristics of adolescents with temporomandibular disorder (TMD) and compared facial macrotrauma effects between young and older adolescents. This case–control study included 70 randomly selected patients (35 young adolescents aged 12–16 years and 35 older adolescents aged 17–19 years) who had been diagnosed with TMD. Each age group was further subdivided according to the presence (T1) or absence (T0) of a macrotrauma history. All patients completed questionnaires on temporomandibular joint (TMJ) pain and dysfunction. We analyzed TMD severity symptoms using TMD-related indexes and the physical changes of TMJ using TMJ MR images. The Symptom Checklist-90-Revised was used to evaluate the patients’ psychological status. Anterior disc displacement was the most frequently observed MRI finding, occurring in a significant proportion of young (47 joints, 67.1%) and older adolescents (40 joints, 57.1%). The prevalence of all the MRI findings (disc displacement, disc deformity, condylar degeneration, and effusion) did not differ between the T0 and T1 subgroups among young and older adolescents. Conversely, the psychological factors differed significantly between the subgroups. Among young adolescents, the mean scores of somatization, obsessive-compulsiveness, hostility, phobic ideation, and psychosis were significantly higher in the T1 subgroup than in the T0 subgroup (all p < 0.05). Furthermore, these increased psychological scores positively correlated with TMD indexes. Clinicians should consider that a weakened psychological status could be an aggravating factor in young adolescents with TMD and should consider the implications in future assessment of such patients.

Evaluation of the efficacy of different treatment modalities for painful temporomandibular disorders

The purpose of this study was to clinically evaluate the efficacies of three treatment methods and to compare their outcomes in patients with painful disc displacement. The study group comprised 45 patients with unilateral temporomandibular disorders who fell into Axis I group II (with limited mouth opening) of the Research Diagnostic Criteria for Temporomandibular Disorders. Magnetic resonance imaging was used for definitive diagnosis. The patients were divided randomly into three groups according to the treatment method: splint therapy, splint therapy with ultrasound-guided arthrocentesis, and splint therapy with low-level laser therapy. Patients were followed up after treatment for 6 months. The groups were compared in terms of pain and functional jaw movements (unassisted mouth opening without pain, maximum unassisted mouth opening, and contralateral movements). At the end of treatment, functional jaw movements were significantly increased while pain values were significantly decreased in all groups (P<0.05). Group 2 had a quicker improvement in terms of mouth opening scores at the end of the first month, and unassisted mouth opening without pain was found to be more than 35 millimetres in all groups at the end of 6 months. All treatment modalities showed effective results on pain and functional jaw movements in the treatment of temporomandibular disorders.

Comparison of the effectiveness of high resolution ultrasound with MRI in patients with temporomandibular joint dısorders

OBJECTIVES

To assess the effectiveness of a high resolution ultrasound for temporomandibular joint (TMJ) evaluation in comparison to MRI in patients with TMJ disorders.

METHODS

Our study comprised 50 patients (35 female and 15 male) with a mean age of 30.61. Clinical examination was performed. Bilateral imaging of TMJ was conducted by using a high-resolution ultrasound and 1.5 Tesla MR. Diagnostic accuracy of ultrasound was assessed for disc displacement and joint effusion in comparison to MRI. Sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy (Ac) were calculated for ultrasound. Measurements were compared by Bland & Altman and intraclass correlation coefficient (ICC). Significance level was set at p < 0.05.

RESULTS

Most frequent complaints were noise 42 (84%) and 34 (68%) pain. For disc position assessment with ultrasound for both sides and closed-open mouth, sensitivity, specificity, PPV, NPV and accuracy ranged between, 0.88 - 1, 0.60 - 0.87, 0.70 - 0.97, 0.75 - 1, and 0.84 - 0.98, respectively. For the diagnosis of effusion with ultrasound for both sides, sensitivity, specificity, PPV, NPV and accuracy ranged between 0.65 - 0.81, 0.91 - 1, 0.96 - 1, 0.45 - 0.46 and 0.72 - 0.84, respectively. ICC values calculated for intraobserver agreement for right and left TMJ for all measurements were found to be statistically significant (p < 0.001). ICC values ranged between 0.964 and 0.995 suggesting excellent correlation among ultrasound and MRI. In general, for ultrasound measurements we found a mean difference ranging between -0.182 and +0.130 mm in comparison to MRI.

CONCLUSION

Ultrasound can be suggested as an adjunct to common imaging modalities in the assessment of TMJ.

Differences among Unique Nanoparticle Protein Corona Constructs: A Case Study Using Data Analytics and Multi-Variant Visualization to Describe Physicochemical Characteristics

Gold nanoparticles (AuNPs) used in pharmaceutical treatments have been shown to effectively deliver a payload, such as an active pharmaceutical ingredient or image contrast agent, to targeted tissues in need of therapy or diagnostics while minimizing exposure, availability, and accumulation to surrounding biological compartments. Data sets collected in this field of study include some toxico- and pharmacodynamic properties (e.g., distribution and metabolism) but many studies lack information about adsorption of biological molecules or absorption into cells. When nanoparticles are suspended in blood serum, a protein corona cloud forms around its surface. The extent of the applications and implications of this formed cloud are unknown. Some researchers have speculated that the successful use of nanoparticles in pharmaceutical treatments relies on a comprehensive understanding of the protein corona composition. The work presented in this paper uses a suite of data analytics and multi-variant visualization techniques to elucidate particle-to-protein interactions at the molecular level. Through mass spectrometry analyses, corona proteins were identified through large and complex datasets. With such high-output analyses, complex datasets pose a challenge when visualizing and communicating nanoparticle-protein interactions. Thus, the creation of a streamlined visualization method is necessary. A series of user-friendly data informatics techniques were used to demonstrate the data flow of protein corona characteristics. Multi-variant heat maps, pie charts, tables, and three-dimensional regression analyses were used to improve results interpretation, facilitate an iterative data transfer process, and emphasize features of the nanoparticle-protein corona system that might be controllable. Data informatics successfully highlights the differences between protein corona compositions and how they relate to nanoparticle surface charge.

MRI assessment and histopathologic evaluation of subchondral bone remodeling in temporomandibular joint osteoarthritis: a retrospective study

OBJECTIVE

The aim of the study was to characterize subchondral bone remodeling by using magnetic resonance imaging (MRI) and histopathologic assessment of temporomandibular joint osteoarthritis (TMJOA) and to analyze the correlations between them.

STUDY DESIGN

The retrospective study was based on 153 joints of 100 patients. These patients had undergone MRI and had been diagnosed with temporomandibular joint internal derangement Wilkes stage IV-V, followed by the failure of conservative or arthroscopic/anchorage treatment. We evaluated and compared 136 joints based on MRI and histopathologic observation. According to the modified Osteoarthritis Research Society International system and the Diagnostic Criteria for Temporomandibular Disorders system, the scores of histopathology and MRI were compared by using kappa categorical agreement analysis.

RESULTS

MRI showed subchondral bone changes in 153 joints, 136 of which had been subjected to surgical treatment and histopathologic assessment. Statistical tests revealed substantial agreement between MRI and histopathology (κ value: 0.779).

CONCLUSIONS

MRI is an effective technique to evaluate the pathologic changes of TMJOA. Our histopathologic grading criteria contributed to the clarification of the occurrence and developmental process of TMJOA. Therefore, the evidence of MRI should be seen as a reference standard for the choice of nonsurgical or surgical therapy in the management of TMJOA.

Metrical analysis of disc-condyle relation with different splint treatment positions in patients with TMJ disc displacement

OBJECTIVE

To evaluate the effect of bite positions characterizing different splint treatments (anterior repositioning and stabilization splints) on the disc-condyle relation in patients with TMJ disc displacement with reduction (DDwR), using magnetic resonance imaging (MRI).

MATERIAL AND METHODS

37 patients, with a mean age of 18.8±4.3 years (7 male and 30 females) and diagnosed with DDwR based on the RDC/TMD, were recruited. MRI metrical analysis of the spatial changes of the disc/condyle, as well as their relationships, was done in three positions: maximum intercuspation (Position 1), anterior repositioning splint position (Position 2), and stabilization splint position (Position 3). Disc/condyle coordinate measurements and disc condyle angles were determined and compared.

RESULTS

In Position 1, the average disc-condyle angle was 53.4° in the 60 joints with DDwR, while it was -13.3° with Position 2 and 30.1° with Position 3. The frequency of successful "disc recapture" with Position 2 was significantly higher (58/60, 96.7%) than Position 3 (20/60, 33.3%). In Positions 2 and 3, the condyle moved forward and downward while the disc moved backward. The movements were, however, more remarkable with Position 2.

CONCLUSIONS

Anterior repositioning of the mandible improves the spatial relationship between the disc and condyle in patients with DDwR. In addition to anterior and inferior movement of the condyle, transitory posterior movement of the disc also occurred.

Trends in maxillofacial imaging

Maxillofacial imaging encompasses radiology of the teeth and jaws, including the temporomandibular joints. Modalities used include intra-oral radiographs, panoramic tomography, cephalograms, cone-beam computed tomography, computed tomography, magnetic resonance imaging, ultrasound, and radionuclide imaging. Common indications for imaging are impacted and supernumerary teeth, dental implants, inflammatory dental disease, and fibro-osseous lesions, cysts, and masses of the jaws. Osteonecrosis of the jaws may follow radiotherapy or the use of bisphosphonates and other drugs. Imaging of the temporomandibular joints and the potential role of imaging in obstructive sleep apnoea are also discussed.

Directional characteristics of incipient temporomandibular joint disc displacements: A magnetic resonance imaging study

INTRODUCTION

Disc displacement (DD) is common in adolescents, but not much is understood about its cause. Assessment of the directionality of incipient DDs may provide clues about the etiology.

METHODS

The sample consisted of magnetic resonance images of 143 temporomandibular joints with incipient DD from 89 preorthodontic patients (mean age, 10.8 years). The severity of DD was evaluated by grading the degree of displacement depicted in the images in the sagittal and coronal planes, and each incipient DD was categorized based on the directionality.

RESULTS

Of the 143 incipient DDs, rotational anterolateral DD (43.36%) and partial anterior DD in the lateral portion (27.27%) were the most common; rotational anteromedial DD (9.09%) and partial anterior DD in the medial portion (1.40%) accounted for only 10.49%. Anterior DD was seen in 12.59%. Pure sideways shift was rare; lateral DD was seen in 2.80%, and medial DD in 3.50%. Thus, the lateral part of the joint was involved in a majority of the incipient DDs and the medial part far less. No sex difference was noted in this trend, but the difference between the right and left sides was statistically significant.

CONCLUSIONS

These results indicate a predilection for the lateral part of the joint in incipient DDs and may have etiologic implications.

The value of MRI in patients with temporomandibular joint dysfunction: Correlation of MRI and clinical findings

AIM

To estimate the correlation between the MRI findings and clinical outcomes in patients with temporomandibular joint dysfunction (TMD).

METHODS AND MATERIALS

We included 546 female and 248 male patients who were clinically diagnosed with TMD (mean age 38.7 years) and examined by MRI (T1 and T2 weighted images, parasagittal and paracoronal slices). A questionnaire, radiological, and clinical findings were analysed for statistically significant correlations. The analysed parameters included gender, age, disk position, joint degeneration, arthralgia, mouth opening, condyle position and clinical progress.

RESULTS

Of all TMJ's 62% showed physiological disc position, 35% anterior and 3% posterior disc position. Modification of therapy occurred in 20% and alteration of diagnosis was found in 32% of all cases. Anterior disc displacement with reduction showed a specificity of 88% and a sensitivity of 78%, whereas anterior disc displacement without reduction showed a specificity of 84% and a sensitivity of 73%. A significant correlation between disc length, condyle morphology and disc displacement was found. With the increase of intra-articular liquid as seen on MRI the level of arthralgia significantly rose as opposed to mouth opening.

CONCLUSION

Specificity and sensitivity, for anterior disc displacement and osseous changes in TMJ were highly acceptable. Results had confirmed the diagnostic capability of MRI in diagnostic imaging of TMJ. Additionally MRI should be used primarily in severe, therapy-resistant cases and for surgical planning purposes.

Correlation between temporomandibular joint morphology and disc displacement by MRI

OBJECTIVES

The aim was to evaluate the morphology of the temporomandibular joint's (TMJs) disc and condyle as well as its correlation with disc displacement, using MRI.

METHODS

190 TMJs were retrospectively analysed. The condyle morphology of each TMJ was evaluated by two observers using both axial and coronal views, as were their disc morphology and displacement, using sagittal view. Condyle morphology was classified as flat, convex, angled or rounded in the coronal sections and as anterior side flat/posterior side convex, biconvex, anterior side concave/posterior side convex, flat or biconcave in the axial view. Disc morphology was determined as biconcave, biplanar, biconvex, hemiconvex or folded. χ2, Fisher exact and Bonferroni correction tests were used to evaluate the data. ANOVA followed by post hoc Tukey's test was used to evaluate the interaction between age and disc displacement.

RESULTS

Anterior disc displacement with reduction; convex condyle morphology in the coronal view; anterior side concave/posterior side convex morphology in the axial view; and biconcave discs were found to be the most prevalent findings. An association was observed between disc morphology and disc displacement (p<0.001). No correlation between condyle morphology and TMJ disc displacement was found (p=0.291 for axial and p=0.14 for coronal views).

CONCLUSIONS

The results of this study suggest that TMJ disc morphology is associated with disc displacement.

Assessing the reliability of MRI-CBCT image registration to visualize temporomandibular joints

OBJECTIVES

To evaluate image quality of two methods of registering MRI and CBCT images of the temporomandibular joint (TMJ), particularly regarding TMJ articular disc-condyle relationship and osseous abnormality.

METHODS

MR and CBCT images for 10 patients (20 TMJs) were obtained and co-registered using two methods (non-guided and marker guided) using Mirada XD software (Mirada Medical Ltd, Oxford, UK). Three radiologists independently and blindly evaluated three types of images (MRI, CBCT and registered MRI-CBCT) at two times (T1 and T2) on two criteria: (1) quality of MRI-CBCT registrations (excellent, fair or poor) and (2) TMJ disc-condylar position and articular osseous abnormalities (osteophytes, erosions and subcortical cyst, surface flattening, sclerosis).

RESULTS

75% of the non-guided registered images showed excellent quality, and 95% of the marker-guided registered images showed poor quality. Significant difference was found between the non-guided and marker-guided registration (χ(2) = 108.5; p < 0.01). The interexaminer variability of the disc position in MRI [intraclass correlation coefficient (ICC) = 0.50 at T1, 0.56 at T2] was lower than that in MRI-CBCT registered images [ICC = 0.80 (0.52-0.92) at T1, 0.84 (0.62-0.93) at T2]. Erosions and subcortical cysts were noticed less frequently in the MRI-CBCT images than in CBCT images.

CONCLUSIONS

Non-guided registration proved superior to marker-guided registration. Although MRI-CBCT fused images were slightly more limited than CBCT alone to detect osseous abnormalities, use of the fused images improved the consistency among examiners in detecting disc position in relation to the condyle.

Assessment of articular disc displacement of temporomandibular joint with ultrasound

PURPOSE

To assess pattern of articular disc displacement in patients with internal derangement (ID) of temporomandibular joint (TMJ) with ultrasound.

MATERIALS AND METHODS

Prospective study was conducted upon 40 TMJ of 20 patients (3 male, 17 female with mean age of 26.1 years) with ID of TMJ. They underwent high-resolution ultrasound and MR imaging of TMJ. The MR images were used as the gold standard for calculating sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of ultrasound for diagnosis of anterior or sideway displacement of the disc.

RESULTS

The anterior displaced disc was seen in 26 joints at MR and 22 joints at ultrasound. The diagnostic efficacy of ultrasound for anterior displacement has sensitivity of 79.3 %, specificity of 72.7 %, accuracy of 77.5 %, PPV of 88.5 %, NPV of 57.1 %, PLR of 2.9 and NLR of 0.34. The sideway displacement of disc was seen in four joints at MR and three joints at ultrasound. The diagnostic efficacy of ultrasound for sideway displacement has a sensitivity of 75 %, specificity of 63.6 %, accuracy of 66.7 %, PPV of 42.8, NPV of 87.5 %, PLR of 2.06, and NLR of 0.39.

CONCLUSION

We concluded that ultrasound is a non-invasive imaging modality used for assessment of anterior and sideway displacement of the articular disc in patients with ID of TMJ.

Evaluation of four different optimized magnetic-resonance-imaging sequences for visualization of dental and maxillo-mandibular structures at 3 T

OBJECTIVES

The purpose of this study was to evaluate four in-house optimized, non-contrast enhanced sequences for MRI-investigation of maxillo-mandibular and dental structures by use of 3 T.

METHODS

12 volunteers with different dental status were examined by using a 3 T MRI with a 20-channel standard head-and-neck coil. All images performed were evaluated by using 3D-techniques, with different slice-thicknesses, in 3D T1- and T2-weighted sequences, as well as by using new techniques of image depictions. In addition phantom measurements were performed to estimate the extent of image artefacts caused by retainers and metal implants.

RESULTS

Mean age of the participants was 33 years (range, 25.5-62.75 years), and the sex ratio was 5 females to 7 males. We identified different techniques to improve osseous and dental structures, despite problems caused by dental implants, tooth crowns or braces.

CONCLUSION

The sequences evaluated offered excellent visualization in 2D and 3D of osseous and dental structures. Anatomical, osseous and dental structures were described at their ROI, in relation to patients with dental and head and neck pathologies. The ability to detect and distinguish pathological processes as soon as possible in 3D with excellent image quality avoiding ionizing radiation remains a challenging domain.

Correlation among the changes observed in temporomandibular joint internal derangements assessed by magnetic resonance in symptomatic patients

PURPOSE

The objective was to assess possible correlations among the anatomy and position of the articular disc, the morphology of the articular eminence and of the condyle, and the presence of joint effusion.

MATERIALS AND METHODS

Magnetic resonance images of 142 joints of symptomatic patients were assessed. The articular disc was classified as normal, elongated, or folded; displacement was classified as normal, anterior with reduction, anterior without reduction, or posterior, lateral, or medial; the condyle was classified as rounded, convex, flattened, or angulated; and the articular eminence was classified as box, sigmoid, flattened, or deformed.

RESULTS

The most frequent forms of the articular disc, articular eminence, and condyle were normal, box, and flattened, respectively. Associations were confirmed between the form of the articular disc and its anterior and lateral positions; between the form of the condyle and an anterior position of the disc; and between the form of the articular eminence and the form of the disc. The form of the articular eminence was the only variant that was not associated to the presence of joint effusion.

CONCLUSIONS

Magnetic resonance imaging allowed the clear observation of articular structures, without attributing a cause-and-effect relation. The prevalence of changes observed was associated with the diagnosis of internal derangement and was statistically proved.

Internal derangement of the temporomandibular joint: is there still a place for ultrasound?

OBJECTIVE

The aim of this study was to assess the diagnostic value of articular sounds, standardized clinical examination, and standardized articular ultrasound in the detection of internal derangements of the temporomandibular joint.

STUDY DESIGN

Forty patients and 20 asymptomatic volunteers underwent a standardized interview, physical examination, and static and dynamic articular ultrasound. Sensitivity, specificity, and predictive values were calculated using magnetic resonance as the reference test.

RESULTS

A total of 120 temporomandibular joints were examined. Based on our findings, the presence of articular sounds and physical signs are often insufficient to detect disk displacement. Imaging by static and dynamic high-resolution ultrasound demonstrates considerably lower sensitivity when compared with magnetic resonance. Some of the technical difficulties resulted from a limited access because of the presence of surrounding bone structures.

CONCLUSIONS

The present study does not support the recommendation of ultrasound as a conclusive diagnostic tool for internal derangements of the temporomandibular joint.

Magnetic resonance imaging-verified temporomandibular joint disk displacement in relation to sagittal and vertical jaw deformities

This retrospective study was designed to analyze the relationships between temporomandibular joint (TMJ) disk displacement and skeletal deformities in orthodontic patients. Subjects consisted of 460 adult patients. Before treatment, lateral cephalograms and TMJ magnetic resonance imaging (MRI) were recorded. Subjects were divided into six groups based on TMJ MRI according to increasing severity of TMJ disk displacement, in the following order: bilateral normal TMJs, unilateral disk displacement with reduction (DDR) and contralateral normal, bilateral DDR, unilateral disk displacement without reduction (DDNR) and contralateral normal, unilateral DDR and contralateral DDNR, and bilateral DDNR. Subjects were subdivided sagittally into skeletal Class I, II, and III deformities based on the ANB (point A, nasion, point B) angle and subdivided vertically into hypodivergent, normodivergent, and hyperdivergent deformities based on the facial height ratio. Linear trends between severity of TMJ disk displacement and sagittal or vertical deformities were analyzed by Cochran-Mantel-Haenszel test. The severity of TMJ disk displacement increased as the sagittal skeletal classification changed from skeletal Class III to skeletal Class II and the vertical skeletal classification changed from hypodivergent to hyperdivergent. There were no significant differences in the linear trend of TMJ disk displacement severity between the sexes according to the skeletal deformities. This study suggests that subjects with skeletal Class II and/or hyperdivergent deformities have a high possibility of severe TMJ disk displacement, regardless of sex.

Computed tomography of the temporomandibular joint

We present a pictorial review of the spectrum of temporomandibular joint (TMJ) pathology diagnosed with CT. Although MRI is the modality of choice for most TMJ pathology, CT is useful when MRI is contraindicated or not accessible. With attention to technique and viewing conditions, CT is capable of showing internal disc derangement, arthritis, neoplasms and non-TMJ regional pathology at a relatively low radiation dose.

MRI analysis of the relationship between bone changes in the temporomandibular joint and articular disc position in symptomatic patients

OBJECTIVES

The aim of this study was to investigate bone changes in the condyle, articular eminence and glenoid fossa in relation to the position of the articular disc.

METHODS

148 temporomandibular joints (TMJs) of 74 symptomatic patients who underwent MRI were evaluated. The position of the disc was classified as either normal (N), disc displacement with reduction (DDwR), disc displacement without reduction (DDwoR) and posterior displacement (PD). Bone changes were investigated in the condyle and temporal components of the TMJ and classified as osteophytosis, sclerosis or erosion.

RESULTS

There were no bone changes in the glenoid fossa of the temporal bone. Of the total number of TMJs studied, 94 (63.5%) were N, 34 (23%) presented DDwoR, 19 (12.8%) presented DDwR and 1 (0.7%) presented PD. The bone changes in the condyle and posterior aspect of the articular eminence were associated with the position of the disc. The bone changes in the anterior aspect of the articular eminence were not associated with the position of the disc.

CONCLUSION

In cases of DDwoR, bone changes in the condyles were more common. The combination of erosion and osteophytosis in the condyle and the bone changes of the posterior aspect of the articular eminence were associated with disc position.

Association between disk position and degenerative bone changes of the temporomandibular joints: an imaging study in subjects with TMD

The aim of this study was to determine the frequency and relationship between disk position and degenerative bone changes in the temporomandibular joints (TMJ), in subjects with internal derangement (ID). MRI and CT scans of 180 subjects with temporomandibular disorders (TMD) were studied. Different image parameters or characteristics were observed, such as disk position, joint effusion, condyle movement, degenerative bone changes (flattened, cortical erosions and irregularities), osteophytes, subchondral cysts and idiopathic condyle resorption. The present study concluded that there is a significant association between disk displacement without reduction and degenerative bone changes in patients with TMD. The study also found a high probability of degenerative bone changes when disk displacement without reduction is present. No association was found between TMD and condyle range of motion, joint effusion and/or degenerative bone changes. The following were the most frequent morphological changes observed: flattening of the anterior surface of the condyle; followed by erosions and irregularities of the joint surfaces; flattening of the articular surface of the temporal eminence, subchondral cysts, osteophytes; and idiopathic condyle resorption, in decreasing order.

Correlation between disc displacements and locations of disc perforation in the temporomandibular joint

OBJECTIVES

The aim of this study was to investigate the correlation between disc displacement types and locations of disc perforation in the temporomandibular joint (TMJ).

METHODS

157 patients (162 joints) with disc perforation observed through arthroscopy were included in this study. The types of disc displacement were analysed by TMJ MRI before operation. The locations of disc perforation under arthroscopy were recorded. The correlation between types of disc displacement and locations of disc perforation was analysed by Fisher's exact test.

RESULTS

Medial disc perforation was observed in 55.6% of patients with anterolateral displacement without reduction, but was observed in only 3.7% of patients with pure anterior displacement, and was not observed in patients with anteromedial displacement without reduction. There was a statistically significant difference between these groups in the incidence of medial disc perforation.

CONCLUSIONS

There is a correlation between different disc displacements and locations of disc perforation. The incidence of medial disc perforation in patients with anterolateral displacement was significantly higher. The types of disc displacement may have direct influence over the locations of disc perforation.

Contemporary imaging of the temporomandibular joint

This article discusses imaging techniques for visualization of the temporomandibular joint. Conventional plain film modalities are discussed briefly, with an emphasis on the more contemporary modalities, such as CT with cone-beam technology, MRI, and nuclear imaging, including single-photon emission computed tomography, and positron emission tomography. Indications, advantages, and limitations are discussed. As advancements in this area continue, our understanding of this complex joint and its pathology will follow, which will lead to more defined imaging indications and ultimately, to improved treatment outcomes.

Internal derangements of the temporomandibular joint

This article discusses several types of internal derangements of the temporomandibular joint. It includes definitions, clinical characteristics, and management options. Nonsurgical and surgical treatment strategies are discussed taking into consideration the latest evidence-based literature.

Current concepts in maxillofacial imaging

A review of state-of-the-art maxillofacial imaging is presented. Current imaging techniques include intra-oral radiographs, dental panoramic tomography, multidetector helical computed tomography, cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI). The commonest conditions encountered in clinical radiological practice are reviewed, including maxillofacial deformities, complicated dental impactions, maxillofacial trauma, jaw lesions (cysts, neoplasms, fibro-osseous lesions (FOLs) and infections), and temporomandibular joint pathology. Pre-operative assessment for dental implant placement is also briefly reviewed.