Microscopy and tomography of erosive changes in the temporomandibular joint. An autopsy study

Stress shielding FE analysis on the temporomandibular joint

Aims

The purpose of this study is to develop a FE model of the temporomandibular joint (TMJ) to investigate a musculoskeletal System of forces able to taking into account the effect of all the muscles on the TMJ in terms of stress evaluated on the bone.

Methods

A 3-dimensional finite element model of the mandible was constructed from the images generated by cone-beam computed tomography of a patient undergoing fixed orthodontic treatment. In order to define the loading force system an exustive study was developed to investigated the entity of the Lateral pterygoid, Masseter, medial pterygoid, Temporalis, and Geniohoid digastric, muscles.

Results

Stresses in the TMJ components (disc, mandible condyle and the fossa eminence on the skull) were obtained. The results have shown stress distribution during normal occlusion.

Conclusion

An appreciation of the anatomical and mechanical features associated with the TMJ can serve as a foundation for understanding a patient's clinical presentation. Performance of a thorough patient history and clinical examination can guide the clinician toward an improved diagnostic process.

Alternative cone-beam CT method for the analysis of mandibular condylar bone in patients with degenerative joint disease

OBJECTIVE

The aim of this study was to investigate the use of 3D microstructural bone analysis in patients with degenerative joint disorder (DJD) to enhance the diagnostic capacity of cone beam computed tomography (CBCT) in the evaluation of bone tissue.

METHODS

147 TMJ CBCT images of 88 participants were assessed with regard to DJD in the mandibular condyle. We divided each condyle into 3 groups (0, 1, 2) according to diagnosis of DJD: 0 indicates normal condyles (control individuals), 1 indicates mild erosive osteoarthritic change (EOC) and 2 indicates severe EOC. 3D fractal dimension (FD) was calculated on CBCT images of mandibular condyle and were compared with the radiographic diagnosis of patients.

RESULTS

ANOVA test showed that there was statistically significant difference in FD values among each groups. The average FD value of group 0 was 1.971, group 1 was 1.918 and group 2 was 1.863. Lower FD values and more severe degenerative changes were seen in patient group 2. To evaluate the reliability of fractal analysis (FA) method, receiver operating characteristic (ROC) curve analysis was performed. Area under the curve (AUC) was 0.717 (p < 0.001).

CONCLUSION

This study provides a preliminary conclusion that fractal analysis may be a helpful tool to enhance the diagnostic capacity of CBCT in the evaluation of DJD.

CBCT analysis of bony changes associated with temporomandibular disorders

OBJECTIVES

The aim of the present study was to compare cone-beam computerized tomography (CBCT) findings and joint space measurement in temporomandibular disorder (TMD) and non-TMD joints, and to correlate these findings with the clinical diagnosis.

METHODS

The study was conducted on patients diagnosed with temporomandibular joint (TMJ) osteoarthritis or closed lock according to the Research Diagnostic Criteria for TMDs (Group IIb, IIc, and III). CBCT and clinical records of non-TMD patients who sought treatment for purposes other than TMD were used retrospectively as a control. The following radiographic criteria were assessed: flattening, osteophyte, Ely's cyst, condylar surface irregularities, and joints' space measurements.

RESULTS

Osteoarthritic joints had significantly more condylar irregularities (P50.0), osteophytes (P50.0), and condylar flattening (P50.003) than non-TMD joints. Osteoarthritic joints had significantlymore superior surface irregularities (P50.0) and osteophytes (P50.006) than closed lock joints.Non-TMDjoints had significantlymore joint space (5.64+1.88) compared with osteoarthritic joints (4.57+1.97), (P50.025). The correlation among TMD, osteophytes, and flattening of the condylar surface was statistically significant (r50.331, Pv0.000).

DISCUSSION

Cone-beam computerized tomography findings are significantly associated with the clinical diagnosis of TMD. Osteophytes and flattening of the condylar surface are common features of TMD.

Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: A comparison study

Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically analyzed with the Mann-Whitney test. The reliability and degrees of agreement between two observers were also determined by the mean of Cohen’s Kappa analysis. Results: CBCT had a statistically significant superiority than other studied techniques in detection of both erosive and osteophytic lesions with different sizes. There were significant differences between tomography and panoramic in correct detection of both erosive and osteophytic lesions with 1mm and 1.5 mm in size. However, there were no significant differences between Tomography and Panoramic in correct detection of both erosive and osteophytic lesions with 0.5 mm in size. Conclusions: CBCT images provide a greater diagnostic accuracy than spiral tomography and panoramic radiography in the detection of condylar bone erosions and osteophytes.

Key words:Bone defect, Condyle, CBCT, Panoramic, radiography.

The temporomandibular joint of California sea lions (Zalophus californianus): part 1 - characterisation in health and disease

OBJECTIVES

This study aimed to characterise the histologic, biomechanical and biochemical properties of the temporomandibular joint (TMJ) of California sea lions. In addition, we sought to identify structure-function relationships and to characterise TMJ lesions found in this species.

DESIGN

Temporomandibular joints from fresh cadaver heads (n=14) of California sea lions acquired from strandings were examined macroscopically and microscopically. The specimens were also evaluated for their mechanical and biochemical properties. Furthermore, if TMJ arthritic changes were present, joint characteristics were described and compared to healthy joints.

RESULTS

Five male and 9 female specimens demonstrated macroscopically normal fibrocartilaginous articular surfaces and fibrous discs in the TMJ. Out of the 9 female specimens, 4 specimens had TMJ lesions were seen either in the articular surface or the disc. Histologically, these pathologic specimens demonstrated subchondral bone defects, cartilage irregularities and inflammatory cell infiltrates. The normal TMJ discs did not exhibit significant direction dependence in tensile stiffness or strength in the rostrocaudal direction compared with the mediolateral direction among normal discs or discs from affected joints. The TMJ discs were not found to be anisotropic in tensile properties. This feature was further supported by randomly oriented collagen fibres as seen by electron microscopy. Furthermore, no significant differences were detected in biochemical composition of the discs dependent upon population.

CONCLUSION

The TMJ and its disc of the California sea lion exhibit similarities but also differences compared to other mammals with regards to structure-function relationships. A fibrous TMJ disc rich in collagen with minimal glycosaminoglycan content was characterised, and random fibre organisation was associated with isotropic mechanical properties in the central region of the disc.

Temporomandibular disorders. Part 1: anatomy and examination/diagnosis

Temporomandibular disorders (TMD) are a heterogeneous group of diagnoses affecting the temporomandibular joint (TMJ) and surrounding tissues. A variety of methods for evaluating and managing TMD have been proposed within the physical therapy profession but these sources are not peer-reviewed and lack updates from scientific literature. The dental profession has provided peer-reviewed sources that lack thoroughness with respect to the neuromusculoskeletal techniques utilized by physical therapists. The subsequent void creates the need for a thorough, research informed, and peer-reviewed source regarding TMD evaluation and management for physical therapists. This paper is the first part in a two-part series that seeks to fill the current void by providing a brief but comprehensive outline for clinicians seeking to provide services for patients with TMD. Part one focuses on anatomy and pathology, arthro- and osteokinematics, epidemiology, history taking, and physical examination as they relate to TMD. An appreciation of the anatomical and mechanical features associated with the TMJ can serve as a foundation for understanding a patient's clinical presentation. Performance of a thorough patient history and clinical examination can guide the clinician toward an improved diagnostic process.

Correlation between bony changes measured with cone beam computed tomography and clinical dysfunction index in patients with temporomandibular joint osteoarthritis

OBJECTIVES

To investigate the correlation between clinical dysfunction index (Di) and condylar bony changes, glenoid fossa bony changes and joint space changes.

METHODS

Clinical data and cone beam computed tomography (CBCT) images of 240 patients with temporomandibular joint osteoarthritis (TMJ OA) were analyzed. The patients were assigned a score of Helkimo's clinical Di ranging from 1 to 25 and thereafter divided into 3 groups by the degree of Helkimo's Di. The condylar bony changes observed with CBCT were graded by the classification method of Koyama et al. Glenoid fossa bony changes and joint space changes were both classified as "positive" or "negative". Spearman's rank correlation test was used to correlate the score or degree of Helkimo's Di with the maximum condylar bony changes, glenoid fossa bony changes, and joint space changes.

RESULTS

There was a significant correlation between the Helkimo's Di score and the maximum condylar bony changes (P ≤ 0.0001) and glenoid fossa bony changes (P ≤ 0.0001), and there was a poor correlation between the Helkimo's Di score and joint space changes (P = 0.184). Furthermore, there was a significant correlation between the degree of Helkimo's Di and the maximum condylar bony changes (P ≤ 0.0001) and glenoid fossa bony changes (P ≤ 0.0001), but there was a poor correlation between the degree of Helkimo's Di and joint space changes (P = 0.346).

CONCLUSIONS

Both the score and degree of Helkimo's Di were highly correlated with maximum condylar changes and glenoid fossa bony changes, but not with joint space changes.

Application of cone beam computed tomography for assessment of the temporomandibular joints

Radiographic examination is essential for the diagnosis and management of temporomandibular joint (TMJ) disorders. The goals of TMJ radiography are to evaluate cortical and trabecular architecture of the bony structures and confirm their integrity, to assess the extent and monitor progression of osseous changes, and to evaluate the response to treatment. Accurate evaluation of the TMJ by conventional radiography is limited by structure superimposition. Cone beam computed tomography (CBCT) provides high-resolution multiplanar images and delivers substantially lower radiation dose, compared with multislice CT. CBCT allows examination of TMJ anatomy without superimposition and distortion to facilitate analysis of bone morphology, joint space and dynamic function in all three dimensions. This article will describe the role of CBCT imaging for the assessment of the TMJ osseous structures and present typical appearances of common pathological conditions of the TMJ.

A comparative study of accuracy of detection of surface osseous changes in the temporomandibular joint using multidetector CT and cone beam CT

OBJECTIVE

The aim of this study was to assess the accuracy and reliability of cone beam CT (CBCT) images compared with multidetector CT (MDCT) images for the detection of surface osseous changes in temporomandibular joints (TMJs).

METHODS

Naked-eye inspection of 110 sites in 10 TMJs from 5 dry human skulls provided the gold standard. Two radiologists interpreted the images. Sensitivity, specificity and kappa statistics were used for analysis.

RESULTS

The sensitivities of both modalities were low and comparable whereas the specificities were high and comparable. Intraobserver reliabilities for CBCT (p=0.0005) and for MDCT (p=0.0001) showed significant agreement. Interobserver reliability was higher for CBCT than for MDCT.

CONCLUSION

CBCT and MDCT accuracy was comparable in detecting surface osseous changes with comparable intraobserver reliabilities. However, since CBCT requires less radiation exposure, it should be encouraged for imaging TMJ with suspected surface osseous changes.

Role of different imaging modalities in assessment of temporomandibular joint erosions and osteophytes: a systematic review

OBJECTIVES

To evaluate the ability of different diagnostic imaging techniques for diagnosing the presence of erosions and osteophytes in the temporomandibular joint (TMJ).

METHODS

A systematic search of PubMed, Medline, all Evidence Based Medicine (EBM) reviews, Embase, Web of Sciences and Lilacs identified nine articles that met the selection criteria: some type of TMJ diagnostic imaging, data from autopsy or dry skull TMJs as gold standard, absence of diagnosed systemic arthritis and evaluation of the presence of erosions and/or osteophytes. A hand search of the references of the selected articles was also performed.

RESULTS

Selected studies evaluated panoramic imaging (unenhanced and colour-enhanced digital subtraction panoramic imaging), axially corrected sagittal tomography, axially corrected frontal tomography, sagittal MRI, CT, high-resolution ultrasound and cone beam CT (CBCT).

CONCLUSIONS

Axially corrected sagittal tomography is currently the imaging modality of choice for diagnosing erosions and osteophytes in the TMJ. CT does not seem to add any significant information to what is obtained from axially corrected sagittal tomography. CBCT might prove to be a cost- and radiation dose-effective alternative to axially corrected sagittal tomography. Combining different radiographic techniques is likely to be more accurate in diagnosing erosions and osteophytes in the TMJ than using a single imaging modality. Diagnostic studies that simultaneously evaluate all of the available TMJ imaging technologies are needed.

Comparison of diagnostic accuracy of film and digital tomograms for assessment of morphological changes in the TMJ

OBJECTIVE

To compare diagnostic accuracy of tomograms obtained with film and three digital image receptor modalities for detection of morphological changes in the temporomandibular joint (TMJ).

METHODS

Lateral and frontal cross-sectional tomograms of 158 TMJs in 80 dry human skulls were obtained with four X-ray receptors: one conventional film (Agfa-Gevaert), two photostimulable phosphor (PSP) plates: VistaScan and Digora PCT and one charge-coupled device (CCD): ProMax. The film and the PSP plate tomograms were exposed in a Cranex Tome X-ray unit and the CCD tomograms in the ProMax X-ray unit. The tomograms were examined by three observers for the presence of morphological changes in the condyle, the mandibular fossa and the articular tubercle. Naked-eye inspection of the articular surfaces of the TMJs performed by the same three observers served as the gold standard for the true presence of morphological changes.

RESULTS

For examination of TMJ changes using lateral and frontal tomograms in combination and lateral tomograms separately, the ProMax modality obtained a significant lower diagnostic accuracy than the other three modalities, between which no significant differences were found. For morphological changes localized to the condyle in which the highest number of changes were present according to the gold standard, the same result was found.

CONCLUSION

The ProMax modality was significantly less accurate than the film, VistaScan and Digora PCT modalities for the detection of overall TMJ morphological bone changes as well as condylar bone changes.

Osseous abnormalities of the mandibular condyle: diagnostic reliability of cone beam computed tomography compared with helical computed tomography based on an autopsy material

OBJECTIVES

We compared the diagnostic reliability of cone beam computed tomography (3DX) and helical computed tomography (helical CT) for the detection of osseous abnormalities of the mandibular condyle, using macroscopic observations as the gold standard.

METHODS

Twenty-one temporomandibular joint autopsy specimens underwent imaging with 3DX and helical CT. The specimens were macroscopically evaluated for cortical erosion or osteophytosis and sclerosis. The images were independently assessed for the same osseous abnormalities. Observations with the two imaging modalities were compared with the macroscopic observations using the McNemar test.

RESULTS

According to the macroscopic observations, 10 of the 21 mandibular condyles and one fossa showed osseous abnormalities. 3DX detected abnormalities in eight of these condyles and helical CT identified abnormalities in seven, giving a sensitivity of 0.80 for 3DX and 0.70 for helical CT. The specificity of the condyle assessment was 1.0 for both 3DX and helical CT and hence, the accuracy was 0.90 and 0.86, respectively. No significant differences were detected between the 3DX and helical CT for assessment of osseous abnormalities of the mandibular condyle (P=0.286).

CONCLUSIONS

The cone beam CT equipment 3DX is a dose-effective and a cost-effective alternative to helical CT for the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

The angle of the articular eminence in modern dentate African-Americans and European-Americans

The purpose of this study was to determine if there were differences in the angle of eminentia of two 20th century populations based on race, age, gender, and number of teeth and whether there was asymmetry of the angles of eminentia. The sample included dry skulls from the Hamann-Todd Osteological collection as follows: 80 African-Americans (AA, 53 males and 27 females) and 62 European-Americans (EA, 49 males and 13 females), ranging in age from 16-77 years. The lateral, central, and medial aspects of the right and left slopes of the articular eminence were measured in a parasagittal plane. Independent t-tests, paired t-tests, and Pearson correlation coefficients were computed. For the AA population, the right central, lateral, and medial angles of eminentia were steeper than the corresponding left angles (paired t-test, p<0.05); for the AE males only the right lateral and medial angles were significantly steeper than the corresponding left angles (paired t-test, p<0.05). There were no significant relationships between age or number of teeth and the angle of eminentia measurements, nor were there differences in angle of eminentia by gender. There were two differences by race: the EA males had steeper left central and left medial angles than the AA males (independent t-test, p<0.05). The central angle of eminentia was consistently steeper than the medial angle (paired t-test, p<0.01), and the lateral was generally steeper than the medial.

Anatomical modifications of the temporomandibular joint during ageing

It is essential to know the normal and pathological changes of ageing in the temporomandibular joint (TMJ) because of the frequency of pathology in this joint and the increased duration of life in current populations. A study was done on 70 TMJs harvested from 35 subjects older than 75 years. These joints were studied macroscopically, radiologically and histologically. Degenerative pathology of the TMJ affected more than 50% of the subjects studied and the disc was perforated in 7%. Ageing of the TMJ without any degenerative pathology is marked by radiographic signs which are not specific to the TMJ (cortical thinning, demineralisation). Histologically, amyloid degeneration was present in nearly 50% of TMJs studied.

Relationship between sex, age, and the minimum thickness of the roof of the glenoid fossa in normal temporomandibular joints

This autopsy study investigates the minimum thickness of the roof of the glenoid fossa of grossly normal temporomandibular joints (TMJ) and correlates this to gender and age. This study was based on 49 TMJ specimens collected from 26 male and 23 female cadavers whose mean age at death was 73.8 years (range=50-96). No information was available about TMJ symptoms before death. A digital micrometer was used to measure the minimum thickness of the glenoid fossae. Comparisons were made based on gender and age. The mean value for the minimum roof thickness of all joint specimens examined was 0.8 mm. Mean values for male and female specimens were 0.8 and 0.7 mm, respectively, which were not significantly different. In addition, no age-related differences were observed. The average thickness was 0.7 mm for individuals in their fifties, 0.8 mm for those in their sixties and seventies, 0.6 mm for those in their eighties, and 0.8 mm for individuals in their nineties. Although these data indicate that the minimum thickness of the glenoid fossa of the TMJ is not significantly correlated with sex or age in patients 50 years of age and older, they nonetheless provide additional information about normal TMJ anatomy, particularly with regard to our knowledge of joint remodeling and function in the disease and non-disease states. Thickness of the glenoid fossa has also been implicated as a factor in facial trauma involving superior displacement of the mandibular condyle into the middle cranial fossa. The thickness of the glenoid fossa is also of potential interest during surgeries involving the glenoid fossa, such as TMJ arthroplasty or joint reconstruction.

Female adolescent facial pattern associated with TMJ disk displacement and reduction in disk length: part I

The aim of this study was to determine whether associations exist between temporomandibular joint (TMJ) disk displacement, and craniofacial morphology in an adolescent sample. Craniofacial lateral cephalometric radiographs and magnetic resonance images of the TMJs were obtained of 119 females between the ages of 10 and 17 years. Once the effects of age had been considered, associations between TMJ internal derangement and craniofacial morphology were studied in 5 facial regions making use of 5 separate multiple regression analyses. In females, associations between altered facial morphology and altered disk position were present within each of the facial regions investigated; the mandibular regions showed the strongest associations. This study shows that functional alteration in TMJ disk dynamics may be another factor to consider when craniofacial growth is forecasted for orthodontic treatment planning.

Age and gender differences in temporomandibular joint radiographic findings before orthodontic treatment in adolescents

OBJECTIVE

The purpose of this study was to determine whether there is a relationship between abnormal temporomandibular joint radiographic findings and age or gender in a sample of young preorthodontic patients.

STUDY DESIGN

A total of 491 consecutive patients, aged 9 to 15 years, were referred for orthodontic records. Routine preorthodontic radiographs, including corrected sagittal tomographs, were taken for each patient and viewed by an observer blinded to clinical records. Temporomandibular joint radiographic findings were classified as normal or abnormal. For comparative purposes, the study population was divided into 2 age groups (9-11 years and 12-15 years).

RESULTS

Frequency of abnormal findings ranged from 2.4% to 11.5% and was similar for both sides. Temporal component abnormalities correlated with abnormalities of condylar position, joint space, and condylar osseous morphology. The frequency of osseous abnormalities was higher in girls and highest in older girls.

CONCLUSIONS

There are significant differences between genders for some temporomandibular joint radiographic abnormalities, and in our study sample the frequency of abnormalities was highest in 12-to-15-year-old girls.

Bone volume in human temporomandibular autopsy joints with and without erosive changes

The aim was to compare the trabecular bone volume (TBV) and the total bone volume (TOBV) of human temporomandibular joints (TMJ) with erosive changes with those of joints without erosive changes. We examined 35 TMJ autopsy specimens from 19 individuals aged 66 88 years. Sagittal sections of the joints were analyzed microscopically for erosive hard-tissue changes. The TBV and the TOBV of the sections were assessed with the aid of computerized image analysis. A significant increase in trabecular and total bone volume was found in condyles with erosive changes (TBV = 21%, TOBV = 54%) as compared with condyles without erosive changes (TBV = 15%, TOBV = 40%). The trabecular bone volume of the temporal component was also increased (TBV = 24%) in joints with erosive changes in the condyle as compared with joints with unaffected condyles (TBV = 16%). The findings indicate that the relative bone mass may play a role in the development of erosive changes in the TMJ.

Bone histomorphometry using interactive image analysis. A methodological study with application on the human temporomandibular joint

The aim was to develop a reproducible method for bone histomorphometry with the aid of a computerized image analysis program, and to examine the variation when assessing the total and the trabecular bone volume. Histologic sections of 18 temporomandibular joint autopsy specimens were read interactively using a cursor. The two parameters total bone volume and trabecular bone volume, of the condyle and the temporal component respectively, were estimated 2 x by 1 observer using 3 different threshold settings: an automatic, a semi-automatic and a manual technique. The threshold was based on the gray-scale distribution of the image. 2 observers read the same sections with the aid of the semi-automatic technique. The intra-observer variation expressed as coefficient of variation ranged between 1.9% and 7.1% for the different parameters, when the automatic threshold setting technique was employed, and between 2.8% and 8.7% with the semi-automatic technique. The manual technique resulted in a high intra-observer variation with a coefficient of variation between 5.2% and 19.9%. There was a systematic difference between the estimates of the 2 observers. In general, intra- and inter-observer variation was higher in the temporal component than in the condyle. The inter-section variation was moderate, the coefficient of variation ranging from 3.8% to 11.1%. The automatic and semi-automatic techniques resulted in comparable intra-observer variation, with a lower bias in the estimates of the semi-automatic technique. By letting one observer apply the semi-automatic technique, it was possible to achieve fast and reproducible analysis of the total and trabecular bone volume.

Pain, tenderness, mandibular mobility, and anterior open bite in relation to radiographic erosions in temporomandibular joint disease

The relationship between radiographic changes and clinical signs and symptoms of the temporomandibular joint (TMJ) was investigated in 39 patients with joint diseases. Radiographic erosions were found in 33% of the TMJ joints, and overall frequency of radiographic changes including remodeling was 47%. Fifty-four percent of the patients had an anterior open bite (AOB). The AOB showed statistically significant correlation to the extension of erosion of the TMJ. Pain expressed by means of a visual analog scale, tenderness to palpation of the TMJ, and pressure pain threshold showed no significant correlation to erosion, but mandibular mobility showed significant negative correlation to erosive changes. In conclusion, AOB is correlated with erosive radiographic changes in this patient group. However, the degree of local pain and tenderness showed no correlation to radiographic changes.

Association between radiographic findings in the mandibular condyle and temporomandibular dysfunction in an elderly population

Our aims were to study the prevalence of abnormal radiographic findings in mandibular condyles and the possible association between such findings and clinical signs and symptoms of temporomandibular dysfunction (TMD) and dental state. Two cohorts of 70-year-old people, 384 men and 484 women, living in Göteborg, Sweden, participated in the study. The first cohort was examined in 1972 and the other one in 1992. Besides a functional and clinical examination, a questionnaire on TMD and panoramic radiography were included. A deviation from the normal appearance of one or both condyles was found in 26% of the subjects (17% of the condyles). There was no significant difference in this respect between the two cohorts. There were in general only minor and no statistically significant differences between those with normal and deviating condylar findings with regard to various TMD signs and symptoms. The subjects in Eichner group A (with dental support in all zones) showed a slightly lower frequency of abnormal radiographic condylar findings (22%) than those in groups B (reduced dental support) and C (edentulous in one or both jaws; both B and C, 28%). It is concluded that abnormal radiographic condylar findings in these elderly people were not at all or only weakly correlated with signs and symptoms of TMD and dental status.

Concavity of the posterior surface of the temporomandibular condyle: clinical cases and autopsy correlation

OBJECTIVES

To elucidate the significance of the radiographic finding of a concavity of the posterior surface of the temporomandibular condyle.

METHODS

Three clinical cases with a concavity were followed up clinically and radiographically. A total of 39 temporomandibular joint (TMJ) autopsy specimens were examined by corrected sagittal tomography and seven condyles with a concavity of the posterior surface found. They were analysed microscopically together with three joints with a normal, rounded condyle.

RESULTS

At follow-up tomography, two of the clinical cases revealed no change while the third patient had erosive changes after 7 months. The microscopic findings of the autopsy specimens varied. The articular cartilage in three of the seven joints with a concavity was similar to that in the normal condyles. The outer surface of the articular cartilage was sometimes uneven and the cartilage thickened, with an irregular junction between the articular cartilage and subchondral bone. In three joints the cartilage in the concavity had been replaced by granulation tissue. All seven joints had increased cellular activity in the concavity.

CONCLUSIONS

The radiographic finding of a concavity in the posterior surface of the condyle is not specific. When small and well-defined it is indicative of remodelling and of osteoarthrosis when larger and with a diffuse outline.