Thickness of the roof of the glenoid fossa and condylar bone change: a CT study

OBJECTIVES: The aim of this study is to investigate the relationship between the thickness of the roof of the glenoid fossa in the temporomandibular joint (TMJ) and the existence and types of condylar bone change. MATERIALS AND METHODS: Helical CT was used to measure the thickness of the roof of the glenoid fossa at its thinnest part in 37 orthodontic patients with temporomandibular disorders. Condylar bone changes were classified into four types: no bone change (24 joints); flattening (19 joints); osteophyte formation (13 joints); and erosion (18 joints). RESULTS: The roof of the glenoid fossa was significantly thicker in joints with bone change than in joints with no bone change (Mann-Whitney U-test, P<0.05). There was also a significant difference in relation to the type of condylar bone change: the thickness of the roof of the glenoid fossa in the erosion group was significantly greater than in the no bone change (P<0.01), flattening (P<0.05) and osteophyte formation (P<0.05) groups (Kruskal-Wallis and Games-Howell tests). CONCLUSION: Compensative bone formation in the roof of the glenoid fossa might help to withstand the increased stress in the TMJ accompanying condylar bone change, especially erosion.     

The utility of panoramic radiography in temporomandibular joint assessment

OBJECTIVES: Panoramic radiography was used to determine (1) intrarater and inter-rater reliability in assessing temporomandibular joint (TMJ) condylar morphology; (2) alteration in condylar shape in patients with temporomandibular disorders (TMD) and controls when matched by age, gender, and state of dentition; and (3) prevalence of condylar abnormalities in individuals with and without TMD. METHODS: One hundred panoramic radiographs were randomly selected from a hospital clinic (45 TMD and 55 non-TMD patients). The images were cropped to include only the temporomandibular apparatus and were independently evaluated by three examiners without knowledge of the patient's clinical status. Multiple statistical tests were performed to evaluate the accumulated data. RESULTS: Intrarater reliability demonstrated substantial agreement, while inter-rater reliability was fair. There was no difference in condylar morphology between patient groups, but mild condylar change was prevalent in all age groups, regardless of TMD status. CONCLUSIONS: Morphological condylar abnormalities are present on panoramic images in all adult age ranges, regardless of status of the dentition or presence of TMD. Condylar shape alone is not an indicator of TMD, and minor condylar discrepancies may have no significance in TMD.     

Relationship of condylar position to disc position and morphology

INTRODUCTION/OBJECTIVE: The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position. METHODS AND MATERIAL: One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging. RESULTS AND DISCUSSION: Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position. CONCLUSION: It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.     

Usefulness of cone beam computed tomography in temporomandibular joints with soft tissue pathology

Objective

The aim of the study was to evaluate the usefulness of cone beam CT (CBCT) in temporomandibular joints (TMJs) with soft tissue pathology.

Methods

106 TMJs of 55 patients with temporomandibular disorder (TMD) were examined by MRI and CBCT. MR images were used for the evaluation of disc displacement, disc deformity, joint effusion and obscurity of temporal posterior attachment (TPA). CBCT images were evaluated for the presence or absence of osseous abnormalities. The χ² test was used to analyse the association between MRI and CBCT findings.

Results

MRI of 106 TMJs revealed disc displacement, disc deformity, joint effusion and obscurity of the TPA in 68, 73, 28 and 27 joints, respectively. Of the 68 TMJs with disc displacement, anterior disc displacement without reduction (ADDWR) was seen most frequently (47/68). CBCT imaging found 65 TMJs were characterized by the presence of osseous abnormalities and were significantly associated with disc deformity and ADDWR (P < 0.05). There was no statistically significant association between the presence of joint effusion and obscurity of TPA and TMJ osseous abnormalities.

Conclusions

TMD patients with confirmed ADDWR or disc deformity on MRI are at risk of having osseous abnormalities in the TMJ and further examination with CBCT is recommended.     

Clinical utility of fluoride-18 positron emission tomography/CT in temporomandibular disorder with osteoarthritis: comparisons with 99mTc-MDP bone scan

Objectives:

The purpose of this study was to compare the clinical utility of fluoride-18 positron emission tomography (¹⁸F-PET)/CT with that of conventional ^99mTc-methylene diphosphonate (MDP) bone scan in temporomandibular disorder (TMD) with osteoarthritis.

Methods:

24 patients with TMD who underwent both ¹⁸F-PET/CT and ^99mTc-MDP bone scans for diagnostic work-up were enrolled. The temporomandibular joint (TMJ)-to-skull uptake ratio, TMJ-to-muscle uptake ratio and TMJ-to-spine uptake ratio on ¹⁸F-PET/CT and the TMJ uptake ratio on bone scan were measured.

Results:

Of the 48 TMJs in 24 patients, 35 TMJs were diagnosed as TMD with osteoarthritis, 8 TMJs as TMD with anterior disc displacement (ADD), and the remaining 5 TMJs showed no evidence of TMD (NED). All three uptake ratios on ¹⁸F-PET/CT and the TMJ uptake ratio on the bone scan tended to be higher in TMD with osteoarthritis than in TMD with ADD or NED. Receiver operating characteristic (ROC) curve analysis for detecting TMD with osteoarthritis indicated that the TMJ-to-skull uptake ratio, TMJ-to-muscle uptake ratio and TMJ-to-spine uptake ratio on PET/CT (0.819, 0.771 and 0.813, respectively) showed higher area under the ROC curve value than the TMJ ratio on bone scan (0.714). The TMJ-to-skull uptake ratio on PET/CT showed the highest sensitivity (89%) and accuracy (81%) of all uptake ratios.

Conclusions:

¹⁸F-PET/CT can help diagnose TMD with osteoarthritis with superior diagnostic ability and is a suitable alternative modality to a conventional ^99mTc-MDP bone scan.     

核素骨显像诊断颞下颌关节病变的临床价值

目的: 探讨利用放射性核素骨三相显像和SPECT检查颞下颌关节紊乱病患者的价值.材料和方法: 66例颞下颌关节紊乱病患者接受X线片、放射性核素骨三相显像和SPECT检查.通过骨扫描结果进行定性和半定量分析,选择23例患者接受外科手术治疗.结果: 选择保守治疗者43例,血池相和延迟相影像及SPECT两侧关节区影像对称.接受颞下颌关节重建术者23例,血池相和延迟相影像及SPECT影像两侧关节区影像不对称,患侧关节区放射性强度和髁状突放射性计数比值稍高于对侧;术中发现,髁状突表面软骨有破坏,术后患者症状缓解.结论: 骨扫描可以作为颞下颌关节紊乱病的早期器质性病变的检测手段,选择为治疗方法提供参考.     

Evaluation of the position, mobility, and morphology of the disc by MRI before and after four different treatments for temporomandibular joint disorders

OBJECTIVES: The purpose of this study was to evaluate changes in disc position, mobility, and morphology in patients with temporomandibular joint disorders (TMD) in response to four different treatments, splint therapy, pumping manipulation, arthrocentesis, and arthroscopic surgery, using magnetic resonance imaging (MRI). METHODS: Eighty-five joints (85 patients) with unilateral internal derangement or osteoarthritis that were successfully treated were included in this study. The patients were divided into four groups as follows: splint therapy group, pumping manipulation group, arthrocentesis group, and arthroscopic surgery group. Changes in the disc position, mobility, and morphology before and after treatment were compared among the four groups using MRI. RESULTS: All discs showed anterior disc displacement (ADD) without reduction before treatment. Only 10% of the joints became ADD with reduction after treatment, and the other joints remained ADD without reduction in spite of treatment. Discs treated by arthroscopic surgery were located more anteriorly compared with pre-treatment. In pre-treatment MRI, the rate of stuck disc increased as the stage of the treatment advanced. In post-treatment MRI, all temporomandibular joints (TMJs) had mobile discs. The disc deformity advanced after arthrocentesis and arthroscopic surgery. CONCLUSIONS: Even though clinical signs and symptoms were alleviated by treatment, most discs remained ADD without reduction on MRI in spite of treatment. This suggests that the four treatments do not necessarily improve the position and deformity of the disc, and that arthroscopic surgery advances the deformity and anterior displacement of the disc. Disc mobility is important for improving clinical signs and symptoms.     

正常人和偏侧咀嚼者颞下颌关节核素骨显像的比较

目的:比较放射性同位素骨三相显像技术对正常人及偏侧咀嚼者颞下颌关节影像检查的差异.材料和方法:正常男性志愿者15名和偏侧咀嚼者20名,接受放射性核素骨三相显像检查,以分析、比较不同咀嚼方式对颞下颌关节及骨的血流和骨代谢的影响.结果:正常人及偏侧咀嚼者两侧颞下颌关节形态对称,偏侧咀嚼者两侧髁状突运动不一致.正常人下颌骨不同部位的骨血流和骨代谢有特定差异.偏侧咀嚼者骨扫描示上述部位差异改变,非咀嚼侧关节区放射性强度稍高于咀嚼侧.结论:放射性同位素骨三相显像可以准确显示颞下颌关节的功能变化.     

Synthetic magnetic resonance imaging for quantitative parameter evaluation of temporomandibular joint disorders

Objective:This study investigated the usefulness of quantitative parameters [longitudinal relaxation (T1), transverse relaxation (T2), and proton density (PD)] obtained with synthetic magnetic resonance imaging (MRI) in assessing the progression of temporomandibular joint (TMJ) disorders.Methods:For individual TMJ disorder diagnoses, the presence of disc displacement in MRI and the osseous change in cone-beam CT were investigated. Joints were classified into three stages: (1) silent stage, no disc displacement or osseous change; (2) incipient stage, presence of disc displacement and absence of osseous change; and (3) progressed stage, both disc displacement and osseous change. In synthetic MRI, the T1, T2, and PD values of the condyle bone marrow were measured simultaneously. The median T1, T2, and PD values were analyzed according to disc displacement, osseous changes, and joint stage.Results:Significant differences were observed in the T1 and PD values of joints with disc displacement or condylar osseous change compared to normal joints. The T1 and PD values also differed between the silent and progressed stages. The PD value differed between the silent and incipient groups, while the T2 value did not differ significantly among the three groups.Conclusion:The PD and T1 values of condylar bone marrow obtained from synthetic MRI can be used as sensitive indicators of TMJ disorder progression. The PD value of the bone marrow showed potential as a useful biomarker for recognizing the initial stages of TMJ disorders. Synthetic MRI is useful for the simultaneous acquisition of effective MRI parameters for evaluating TMJ disorders.     

Severity of synovium and bone marrow abnormalities of the temporomandibular joint in early rheumatoid arthritis: role of gadolinium-enhanced fat-suppressed T1-weighted spin echo MRI

PURPOSE: Our goal was to evaluate the efficacy of dynamic contrast-enhanced fat-suppressed MRI of the temporomandibular joint (TMJ) in detecting early joint involvement in patients with rheumatoid arthritis (RA). METHOD: Conventional T1- and T2-weighted, gadolinium-enhanced T1-weighted, and dynamic gadolinium-enhanced fat-suppressed SE imaging sequences were performed in 22 patients with RA. RESULTS: The dynamic gadolinium-enhanced fat-suppressed T1-weighted SE sequence was more sensitive than the other techniques in detecting early changes in inflamed synovium of periarticular tissue and in detecting condylar bone marrow involvement. In patients with RA, 17 joints with joint pain showed synovial proliferation in 10 (59%) cases and joint effusion in 4 (24%). Of 14 joints with joint sound, 4 (29%) showed synovial proliferation and 7 (50%) showed joint effusion. A lower positional change of the disk was observed in joints with RA than in those with TMJ disorders (82 patients). CONCLUSION: Gadolinium-enhanced fat-suppressed MRI was extremely effective in diagnosing early changes of the inflamed TMJ.     

Correlation between the disc status in MRI and the different types of traumatic temporomandibular joint ankylosis

Objectives:

We aimed to investigate the correlation between the disc status in MRI and the different types of traumatic temporomandibular joint (TMJ) ankylosis.

Methods:

51 consecutive patients (69 joints), diagnosed with traumatic TMJ ankylosis with a residual condyle (Types A2 and A3), were included in this study. All patients had pre-operative MRI, which was reviewed to determine the disc shape, length and position. The results were compared using the Mann–Whitney test.

Results:

There were 37 joints of Type A2 ankylosis and 32 joints of Type A3. All joints of Type A2 and 27 joints of Type A3 (84.4%) definitely had a discernible disc, while 5 joints of Type A3 had no discernible discs. Among the discernible discs, the lateral disc of Type A2 and the whole disc of Type A3 had severe deformity, while the medial disc of Type A2 had mild deformity. The mean (standard deviation) disc length was 10.88 (1.19) mm in Type A2, but 7.50 (0.82) mm in Type A3. There was a significant difference between Types A2 and A3 (p < 0.05). As for the disc position, the intermediate position was found in all joints.

Conclusions:

There is a correlation between the disc status and the different types of traumatic TMJ ankylosis. Therefore, MRI examination is needed to help treatment planning and predict post-operative TMJ function.     

Relationship between increased horizontal condylar angle and resorption of the posterosuperior region of the lateral pole of the mandibular condyle in temporomandibular joint internal derangement

OBJECTIVES: The purpose of this study was to analyse the relationship between horizontal condylar angle, temporomandibular joint (TMJ) disk displacement and resorption of the lateral pole of the mandibular condyle (RLC). METHODS: The study comprised 162 TMJs (81 patients). Disk displacement was assessed and the horizontal angle of the condyle was measured on axial MR images. RLC was assessed on oblique frontal projection plain radiographs. RESULTS: The horizontal angle was increased in joints with disk displacement without reduction (one-factor ANOVA and Scheffe's f-test, P<0.05). The angle was greater in joints with RLC than in the joints without RLC (Student's t-test, P<0.05). CONCLUSIONS: Results suggest that the horizontal condylar angle is increased in joints with disk displacement without reduction. A possible relationship exists between RLC and increased horizontal condylar angle.     

Magnetic resonance imaging of the temporomandibular joint: diagnostic difficulty caused by extensive pneumatization of the mastoid air cells

Objective. During routine MR imaging of temporomandibular joints we have observed that an area of low signal is sometimes identified within the temporal bone overlying the glenoid fossa on proton-density sequences. This finding at times simulates a mass. CT in this situation has demonstrated marked pneumatization of the mastoid air cell extending to that portion of the temporal bone overlying the glenoid fossa. We undertook a clinical study to determine the frequency and appearance of such a finding. Design and patients. We reviewed the images of 12 patients who underwent both MR and CT examinations of their temporomandibular joints. The authors, by consensus, graded all 24 joints using a four-point scale for the presence and appearance of a low-signal area overlying the glenoid fossa on the MR images prior to seeing the corresponding CT images. We then compared our grading with the findings on CT to assess for the presence and extent of pneumatization of the temporal bone overlying the glenoid fossa. Results. Of the 24 joints reviewed there was identical extent of low signal on MR imaging and extent of pneumatization on CT in 22 of 24 joints. In two of the 24 joints assessed there was overestimation of pneumatization due to extensive sclerosis secondary to surgery. Conclusion. The findings of an area of low signal overlying the glenoid fossa on a T2-weighted scan of a nonoperative temporomandibular joint is often due to extensive temporal bone pneumatization of the mastoid air cells. Recognition of the nature of this finding will avoid mistaking it for a fibrous or osseous lesion. Patients with previous operative history may, however, require further investigation with CT. Received: 14 May 1999 Revision requested: 23 June 1999 Revision received: 6 August 1999 Accepted: 6 August 1999     

Pathologic-sonographic correlation in temporomandibular joint pathology

The accuracy of high-resolution ultrasonography (HR-US) in detecting disk displacement and condylar erosion of the temporomandibular joint (TMJ) was evaluated, using corresponding cryosections as a “gold standard”. HR-US of the TMJ was performed with a high frequency 12 MHz transducer on 30 preserved autopsy specimens. Succeeding sonography, the autopsy specimens were deep-frozen and cut in paracoronal planes corresponding to the sonographic images. HR-US diagnoses were compared with cryosectional findings in a blinded fashion. HR-US detected 19 (95%) of 20 instances of condylar erosion and 16 (73%) of 22 instances of disk displacement. There were one false-positive finding for condylar erosion and two false-positive findings for disk displacement. The accuracy of HR-US evaluating condylar erosion and disk displacement rated 93% and 73%, respectively. In conclusion, condylar erosion was reliably assessed by HR-US, but the evaluation of disk position was less accurate.     

Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.     

Computed tomography of the masticatory system--a review

Computed tomography (CT) is a practical method for evaluating the masticatory system, since it shows the bone structures and soft tissues at the same time. It enables one to measure the densities and dimensions of various tissues. All parts of the temporomandibular joint (TMJ), condylar process, mandibular fossa and disc and the main masticatory muscles are well demonstrated by CT in projections which are not possible with other radiological methods.     

Facial skeleton remodeling due to temporomandibular joint degeneration: an imaging study of 100 patients

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.     

Alteration of the horizontal mandibular condyle size associated with temporomandibular joint internal derangement in adult females

OBJECTIVES: The purpose of this retrospective study was to analyse the relationship between horizontal size of the mandibular condyle and internal derangement (ID) of the temporomandibular joint (TMJ). METHODS: One hundred and thirty-nine joints in 88 women aged over 18 years were included in this study. The horizontal condylar size was measured in the antero-posterior and medio-lateral (ML) dimensions using axial magnetic resonance (MR) images. Radiological findings of ID were also assessed from MR imaging. RESULTS: The condyles in the joints with permanent disk displacement were smaller than those in joints without displacement in both dimensions (Fisher's protected least significant difference, P<0.05). There were statistically significant correlations between horizontal condylar size in the ML dimension and both disk morphology and radiological stage of ID (Spearman's correlation coefficient by rank, P<0.05). CONCLUSIONS: The results of this study suggest a possible relationship between horizontal condylar size and disk displacement. It is also suggested that the condyle becomes smaller in the ML dimension with advancement of ID.     

Diagnostic performance of magnetic resonance imaging for detecting osseous abnormalities of the temporomandibular joint and its correlation with cone beam computed tomography

Objective

With cone beam CT (CBCT) as the reference standard, the objective of this study was to determine the diagnostic accuracy of MRI for assessing osseous abnormalities of the temporomandibular joint (TMJ).

Methods

106 TMJs from 55 patients with temporomandibular disorder were examined by CBCT and MRI. CBCT images were evaluated by two experienced oral radiologists with regard to the presence or absence of each of the following eight types of osseous abnormalities: Type 1, destructive and erosive osseous changes of the condyle; Type 2, flattening of the articular surface of the condyle; Type 3, deformity of the condyle; Type 4, sclerosis of the condyle; Type 5, osteophyte formation; Type 6, ankylosis; Type 7, erosion of the articular fossa and/or eminence; and Type 8, sclerosis of the articular fossa and/or eminence. For detection of these osseous abnormalities by MRI, proton density-weighted images and T₂ weighted images were evaluated independently by three observers. Using CBCT findings as the reference standard, the diagnostic performance of MRI for detecting various types of osseous abnormalities was evaluated by calculating its sensitivity and specificity.

Results

Out of 106 joints, CBCT revealed Types 1, 2, 3, 4, 5, 6, 7 and 8 abnormalities in 25, 19, 26, 20, 14, 5, 19 and 22 joints, respectively. The mean sensitivities of MRI among the three observers for detecting Types 1, 2, 3, 4, 5, 6, 7 and 8 abnormalities were 61%, 30%, 82%, 40%, 48%, 34%, 61% and 41%, respectively, whereas the mean specificities were 86%, 92%, 91%, 95%, 84%, 98%, 89% and 91%, respectively.

Conclusions

Although high specificity (84–98%) was obtained with MRI, this modality showed relatively low sensitivity (30–82%) for detecting osseous abnormalities of the TMJ. The value of MRI for the detection of TMJ osseous abnormalities is considered to be limited.