Investigating the position and morphology of the condyle in patients with TMD and asymptomatic subjects, using CBCT

Dissertation for obtaining a specialized doctorate in oral and maxillofacial radiology

Abstract:

Introduction and purpose: The purpose of radiological evaluation of the temporomandibular joint (TMJ) is to depict suspected clinical disorders. This study was conducted with the aim of comparing the position and morphology of the condyle in symptomatic and asymptomatic patients with the help of CBCT. Materials and Methods: The study was descriptive and cross-sectional. In this study, based on RDC/TMD criteria, 25 patients (5 men and 20 women) who were suffering from temporomandibular joint disorders (TMD) were randomly selected during 6 months from among the patients referred to the prosthodontics department of Mashhad Dental School. Also, for the control group, they were selected from people who had normal TMJ and were referred to the radiology department for CBCT imaging in order to implant a dental implant in the posterior maxillary region. There were 21 people in this group, including 8 men and 13 women. CBCT images of the patients were taken by the promax device with the mouth closed at maximum interdental contact. Then, linear measurement of the upper, anterior and posterior articular spaces between the condyle and the glenoid cavity, as well as determining the slope of the joint prominence by the landmarks defined in the sagittal images and evaluating the morphology of the condylar head in three sagittal planes (round, anterior) flattening, posterior flattening), coronal (round, convex angulated) and axial (Elliptical, convex-concave, ovoid) and the dimensions of the condyle head were measured in axial images. The information obtained was analyzed by Fisher's exact tests, independent t, Pearson and Spearman correlation coefficients. (?=0.05) was considered.

Finding In the asymptomatic group, the average upper joint space was 3.3, anterior joint space was 2.3, and posterior joint space was 1.2 mm, and in the symptomatic group, it was measured as 3.1, 2.8, and 2.08 mm, respectively. In the normal group, the Pearson correlation coefficient between age and the anterior posterior dimension of the condyle was significant (r = -0.47 and p = 0.002). The findings showed a significant correlation between the size of the upper joint space and Posterior is present in the normal (p<0.000 and r=0.61) and symptomatic (p<0.000 and r=0.51) groups, but the correlation coefficient between the upper and anterior space dimensions was significant only in the symptomatic group. (p=0.001 and r=0.45). The results showed that there is a significant correlation coefficient only between the slope of the articular eminence and the size of the upper and posterior joint spaces in the normal group. (r=0.33, p=0.03 and r=0.42, p=0.006, respectively) Morphology groups had condyle head in the sagittal plane (p=0.003). The mean slope of the articular protrusion in the sub-groups Round with AnteriorFlattening (p=0.035), and Round with Posterior Flattening also had a significant difference. (p=0.023)

Conclusion: This study showed that the shape of the condyle in coronal and sagittal sections in asymptomatic people and Patients with TMD are related to each other. In addition, the average anterior space between these two groups had a significant difference. Therefore, CBCT imaging provides useful and effective information on the morphology and position of the condyle, which can help in the diagnosis of TMD patients and people prone to joint disorders.

Key words: temporomandibular disorders (TMD), cone beam computed tomography (CBCT), condyle morphology

Introduction:

The purpose of radiological evaluation of the temporomandibular joint (TMJ) is to depict suspected clinical disorders. Clinical evaluation of the temporomandibular joint has certain limitations. Studies show that the clinical examination alone is not able to detect all TMJ joint conditions. TMJ imaging is necessary to supplement the information obtained from clinical examination, especially when a bony abnormality is suspected and conservative treatment has failed or symptoms are worsening.2

The shape of the condyle is considerably variable. This difference in shape may cause problems in its radiographic interpretation. This issue highlights the importance of familiarizing and understanding the variations of the natural view. 2

The radiographic joint space is a general term used to describe the radiolucent area between the condyle and the temporal component. Because the external limits of the radiographic glenoid fossa and The condyle is similar to a smooth sphere and the condyle is not aligned, so the joint space varies from the inside to the outside of the joint. 2

Temporomandibular joint disorders (TMD) are the most common cause of facial pain after dental pain, and its clinical symptoms include muscle pain, joint pain, limitation in mandibular movements, and joint sounds. 2

The reason for overlapping morphological disorders in symptomatic and asymptomatic patients, radiological images should always be interpreted based on clinical findings. . Also, the choice of imaging method should be based on clinical examination. 1

Recently, CT scanners with cone beam (CBCT) have been designed for the maxillofacial areas, which are able to provide spatial resolution of less than mm, with shorter scanning times and lower radiation dose. Although CBCT does not image soft tissue, it is indirectly able to provide information in this 3.

Since there was no study on condyle morphology in patients with TMD and asymptomatic individuals in Iran, so this study aimed to compare the position and morphology of the condyle in symptomatic patients and asymptomatic individuals with the help of CBCT in the state of maximum interdental contact in Mashhad Dental Faculty.

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Temporomandibular joint:

Anatomy of the temporomandibular joint:

The mandible and the temporal bone form the bony parts of the jaw joint. The head of the condyle includes the lower part and the glenoid fossa and the articular tubercle of the temporal bone include the upper bone part. 6

Condyle:

The condyle is a bony and oval structure that is connected to the ramus of the mandible by a narrow neck. The condyle is approximately 20 mm in the internal-external dimension and 8-10 mm thick in the anterior-posterior dimension. 7

The shape of the condyle is considerably variable. This variation in shape may cause problems in the interpretation of radiographic images. This problem emphasizes the importance of knowing the range of the normal appearance of the condyle shape.