Diagnostic Imaging Of The TMJ Done by: afnan zbidat , kholod fahoum , siham othman

1. Diagnostic Imaging Of The TMJDone by: afnanzbidat, kholodfahoum, sihamothman

2. Application OF Diagnostic Imaging • TMJ Imaging is needed as a supplement information obtained from the clinical examination in certain cases: • Conservative treatment has failed • Symptoms are worsening • History of trauma • Significant dysfunction and changes in occlusion • Alteration in range of motion

3. The Purposes of TMJ imaging are: • 1. TO evaluate the integrity and relationships of the hard and soft tissues. • 2.Confirm the extend or stage of progression of known disease. • 3.Evaluate the effect of treatment. As usual , by correlation the radiographic information with the Hx of the patient and the clinical findings we arrive the final diagnosis and put the tx plan according to it.

4. ANATOMY OF THE TMJ • The components of the TMJ: 1.condyle 2. Mandibularfossaof the temporal bone 3. Inter-articular disk 4.Fibrous capsule => lined with synovial membrane surrounds the joint that secrets synovial fluid which lubricate the joint 5.Ligaments & muscle => Restricted or allow movement of the condyle.

5. CONDYLE • It’s a bony structure connected to the mandibular ramus by a narrow neck.

6. Radiographs of condyles in children may show little or no evidence of cortical bone, due to absence of it’s complete calcification which is normally until 2o years of age. • In the absence of disease, the cortical borders in adults are visible radiographically

7. MADIBULAR / GLENOIND FOSSA • The inferior aspect of the squamous part of the temporal bone is composed of: • 1. The glenoidfossawhere the condyle articulates. • 2. Articular eminence

8. S-Shapewhere viewed in the sagittal plane. • The condyle and the mandibular fossa are covered with a thin layer of fibrocartilage which is not visible radiographically. • They develop during the first 3 years and reach mature shape by the age of 4 years

9. Soft tissue components of the TMJ • Inter-articular disk Posterior attachment

10. Inter-articular disk • Composed of fibrous connective tissue, it’s located between the condylar head and mandibular fossa. • It divides the joint cavity into 2 compartments, called the inferior and superior joint spaces. • A normal disk has a biconcave shape with thick anterior band, thicker posterior band and a thin middle part.

11. Posterior Attachment (Retrodiskal tissue) • Consist of a bilaminar zone of vascularized and innervated loose fibroelastic tissue, • superior lamina which is rich in elastin stretch -> disk movement forward with condylar translation. • It’s responsible for the smooth recoil of the disk posteriorly as the mandible close.

12. TMJ BONY RELATIONSHIP • Radiographic joint space contains the soft tissue components of the joint. • The condylar position within the fossa can be determined and compared by the dimensions of the radiographic joint space viewed on corrected lateral images. • When the condyle is: • 1.Centrically positioned: anterior and posterior aspects of the radiolucent joint space are uniform in width. • 2. Retruded: Post < Ant • 3. Protruded: Post > Ant

13. Retruded Centric Protruded

14. Markedly eccentric condylar positioning usually represents an abnormality, as the condyle is positioned: • 1.Inferiorly (widening joint space) => seen in cases fluids or blood within the joint. • 2. Superiorly ( reduced joint space or no space with osseous contact of joint components) => seen in cases of loss or displacement or perforation of intracapsular soft tissue components. • Posterior: disk displacement cases. • Anteriorly: Juvenile rheumatiod arthritis.

15. CONDYLAR MOVEMENT • During mandibular opening as the condyle rotates and translates downward and forward, the disk’s superior surface also moves forward together with it, and slides against the AE.

16. At maximum opening, the condyle moves downward and forward to the apex of the AE or slightly anterior to it. • At Reduced condylar translation => no downward and forward movement and condyle stays on the mandibular fossa, this seen in patients with reduced degree of mouth opening. • Hyper-mobility of the joint =>it’s the movement of the condyle more than 5 mm anterior to the AE, which may permit anterior locking or dislocation of the condyle.

17. IMAGING TECHNIQUES • Selection the type of the imaging techniques depends on several things: • 1.The specific clinical problem ( whether imaging of hard or soft tissue is desired) • 2. The amount of diagnostic information available from a particular imaging modality. • 3.The cost of the examination. • 4.Radiation dose.

18. Imaging Techniques • Soft tissue structures osseous structures

19. Osseous Structures

20. Panoramic Projection • Provides an overall view of the teeth and jaws. • Provides means of comparing left and right sides of mandible. • Serves as screening projection to identify odontogenic diseases and other disorders that may be source of TMJ symptoms. • Gross osseous changes in the condyle may be identified.

21. Dis-advatages: • Doesn’t give information about the condylar position or function. • Mild osseous changes maybe obscured. So it should be supplemental not used as a sole imaging

22. Plain film Imaging modalities • Usually consist of a combination of several projections to allow visualization of the TMJ in various planes, each one has specific position of the mandible when taken, either closed and/or opened mouth or protruded.

23. Computed Tomography • It gives a 3 dimentional images for the internal component of the joint, with an excellent images of the osseous structures. • Types: • Conventional CT (Medical CT) => Provide image of the surrounding S.T • Cone beam CT (CBCT) => ADV: Reduced patient dose compared with medical CT. Both can’t produce accurate image of the articular disk.

24. It’s useful in determining the presence and extent of: • 1.Ankylosis • 2.Neoplasms • 3.Degree of bone involvement in some arthritides.

25. Conventional Tomography • Produce multiple thin image slices that permit visualization of the osseous structures essentially free of superimposition of overlapping structures. • Deplict true condylar position and revealing osseous changes.

26. Both Plain film imaging modalities and conventional tomography are gradually being replaced with more advanced imaging such as cone beam CT.

27. Soft Tissue Structures

28. Indications : 1.TMJ pain and dysfunction are present 2.Clinical finding suggest displacement along with the symptoms and are unresponsive to conservative therapy. 3.When results are expected to influence the treatment plan.

29. Magnetic Resonance Imaging - MRI • Display the articular disk and surrounding structures. The osseous structures of the TMJ also can be displayed but not in details as the CT. • Non invasive technique and doesn’t use ionizing radiation as in Arthrography imaging, it has magnetic field instead and radio frequency pulse.

30. Contraindications: • Pacemakers • Intracranial vascular clips • Metal particles in vital structures • Inability to remain motionless and claustrophobia patients. • Pregnant woman

31. Radiographic abnormalities of the TMJ

32. Condylar hyperplasia • Developmental abnormalities results in enlargement and occasionaly deformity of the condylar head. • males. • unilateral • Discovered before the age of 20 • Tends to arrest with the termination of skeletal growth. Causes: • 1. Hormonal influences • 2.Trauma • 3.Infection • 4.Hereditary • 5.Hypervascularity

33. Radiographic Features • The condyle may appear relatively normal but symmetrically enlarged . • Condylar head & neck elongation • Increase in vertical dimension of the ramus • More radiopaque because of the additional bone present • D.D :A condylar tumor like osteochondroma

34. OPG of condylar hyperplasia involving the right side PA skull view of same patient, showing asymmetry

35. Condylarhypoplasia • Condylarhypoplasia is failure of the condyle to attain normal size . • Normal morphology but smaller in size. • Causes: • Congenital (unilateral or bilateral) or developmental (usually unilateral) abnormalities. • Birth trauma • Intra-articular inflammatory lesion • Therapeutic radiation • infection

36. Radiographic features: Radiographic Features • The condyle may be normal in shape and structure but is diminished in size. • The condylar neck and coronoid process usually are very slender. • Resulting in a mandibular asymmetry and occasional dental crowding. • D.D : Condylar destruction from juvenile rheumatoid arthritis

37. A panoramic image revealing hypoplasia of the left condyle. In this case the hypoplasia is restricted to the condylar head and neck with minimum involvement of the mandibularramus and body.

38. Juvenile arthrosis (boeringarthrosis) • It’s a condylar growth disturbance manifests as hypoplasia & morphological abnormalities. • Unilateral or bilateral. • Incidental panorama or pt may have TMD signs. • Females. • Affects the children or adolescence during the period of mandibular growth.

39. Radiographic features: • Has the characteristic of "toadstool“ appearance. • The condylar neck is shortened & sometimes its absent . • Marked flattening and elongation of the articulating condylar surface.

40. Panoramic Image of Juvenile Arthrosis. The condylar heads have a “ toadstool ” appearance and are posteriorly inclined. The condylar necks are absent.

41. Coronoid hyperplasia • There will be elongation of the coronoid process. • It can be acquired(unilateral or bilateral) or developmental(usually its bilateral). • Best seen by panorama,waters , lateral temographic views & C.T • males • It causes restriction of the condylar movements & inability to open the mouth. • Painless

42. Radiographic Features • The coronoid processes are elongated & large. • More radiopaque . (CT)Sagittal Tomogram of Coronoid Hyperplasia. The coronoid process is elongated and extends above the inferior rim of the zygomatic arch (arrow) but otherwise is shaped normally.

43. Bifid condyle • Caused by deep vertical cleft in the condylar head • Usually its unilateral • Best seen in the frontal or sagittal plane, or actual duplication of the condyle. • The mandibularfossa may remodel to accommodate the altered condylar morphology.

44. Radiographic Features • Deep depression on the condylar surface giving heart shape .

45. Soft tissue abnormality • Internal dearrangement: • which is an abnormality in the position (displacement) or the morphology of the articular disk that can interfere with the normal function. • Unknown etiology. • It can affect anyone • Unilateral or bilateral. • Technique of choice is MRI .

46. Disk displacement • In the maximum intercuspation Anterior disk displacement is the most common when the posterior band disk is located anterior to it’s normal position.

47. During displacement: Disk reduction : when the disk reduce to normal, it has rapid posterior movement with double clicking. :Disk nonreduction When the disk remains anteriorly displaced and the disc will undergo permanent deformation losing it's bioconcave shape.

48. Perforation and deformity • Perforations between superior and inferior joint spaces. • Most commonly occur in the retrodiskal tissue. • Detected by arrthrographic investigations .

49. Disk defortmities : may be accompanied by changes in the signal intensity . Sagittal MRI: Sever deformity of the disk and increase in the tissue signal (erosion)

50. Remodeling and arthritis conditions • Remodeling is an adaptive response of cartilage and osseous tissue to forces applied to the joint that may be excessive. • Occurs through adult life so it's normal unless clinical signs and symptoms of pain present & if there is sever remodeling appears in the R.G.