1. Diseases affecting Temporomandibular Joint (2)
口腔病理學
Diseases affecting Temporomandibular Joint (2)
顳 顎 關 節 疾 病 (2)
陳玉昆教授: 高雄醫學大學 口腔病理科
~2755

2. 學 習 目 標 Understanding: 1. Temporomandibular joint disorders
2. Patient evaluation
3. Examination
4. Imaging
5. Main pathological conditions affecting TMJ

3. 參考資料
References:
Oral Pathology for the Dental Hygienist. Olga AC Ibsen, Joan Anderson Phelan, 4th edition, 2004, Chapter 10, p
Eric Whaites: Essentials of dental radiography & radiology 3rd edition, Chapter 29, p
自購網路資源：super_toolcool

4. Normal Joint Function
Harmonious function of temporomandibular joint depends on various factors.
Anatomic relationship of condyle-disk complex governs smooth functioning of mandible.
Whereas muscles of mastication are the machinery that powers mandibular movement, anatomic joint structures, such as condyle, articular eminence, and disk, act as the gears or bearings of the jaw.
Refs. 1, 3

5. Normal Joint Function
Normal joint function the jaw begins at a rest position of maximum occlusal contact.
In this position, condyle rests within glenoid fossa, with articular disk situated between condyle, roof of glenoid fossa, and articular eminence.
Rest
position
Mouth closed
Refs. 1, 2

6. Normal Joint Function
Rotary and translatory movements of condyle
during normal mouth opening
Rest
position
Mouth
closed
Primary
rotation
opened
Translation
initially
widely
Secondary 1 2 3 4
Ref. 2

7. Temporomandibular Disorders
Temporomandibular disorders (TMDs) are caused by abnormalities in the functioning of temporomandibular joint or associated structures and these have been a clinical & diagnostic challenge in dentistry for many years.
Most studies suggest that clinically significant TMD-related jaw pain, dysfunction, or both affects about 5% of the general population.
Significant more frequent and more severe TMD signs & symptoms are seen in women & older adults.
Ref. 1

8. Pathophysiology of Temporomandibular Joint Disorders
Trauma affecting the temporomandibular joint is classified as direct (assault), indirect (whiplash injury), or secondary to parafunctional habits (clenching, bruxism).
Other contributing factors include dentofacial deformities and psychosocial factors.
TMDs may also be the result of disorders in growth & development (condylar hyperplasia or hypoplasia).
Ref. 1

9. Pathophysiology of Temporomandibular Joint Disorders
Iatrogenic causes of TMDs include indiscriminate use of corticosteroid injection into the joint.
Numerous studies continue to dispute the significance of occlusal relationships.
TMJ abnormalities are also associated with a systemic diseases such as rheumatoid arthritis and osteoarthrities.
Ref. 1

10. Patient Evaluation History Trismus Malocclusion
Parafunctional habits (bruxing, clenching)
Dental symptoms
Extensive dental or orthodontic treatment
History of surgical treatment of jaws
Progression of symptoms (sudden, gradual)
Precipitating events (mastication, spontaneous, yawning)
Ref. 1

11. Examination Ausculation (using a stethoscope) and palpation.
Clinician relates joint noises such as clicking, crepitus (crackling), or popping to the mandibular movement cycle.
Muscles of mastication are palpated to determine tenderness.
Patient is asked to move the mandible in a normal rotation (hinge) and translatory (forward slide) cycle.
Interincisal opening is measured with any obvious deviation of motion to the right or left side.
Ref. 1

12. Examination
Patient’s ability to manipulate the mandible into right and left lateral excursions is noted.
Patient is asked to protrude mandible to determine whether any deviations or disk interferences exist within joint.
Patient’s occlusion is evaluated to determine gross abnormalities and whether occlusal abnormalities are related to patient’s temporomandibular problem.
Ref. 1

13. Investigations Conventional radiographic projections
Other techniques and investigations
Transcranial
Transpharyngeal
Panoramic
Reverse Town’s
Transorbital
Tomography, linear

14. Summary of different parts of TMJ shown by conventional projections
Transcranial Lateral aspect of:
Glenoid fossa
Articular eminence
Joint space
Condylar head
Transpharyngeal Lateral view of:
Condylar head & neck
Articular eminence
Dental panoramic Lateral view of
tomograph both condylar heads
Reverse Towne’s Posterior view of:
both condylar head & necks
Transorbital Anterior view of:
Condylar head & neck
Articular eminence
Tomography All aspects of:
Glenoid fossa Articular eminence
Joint space Condylar head
Ref. 1

15. Main pathological conditions affecting TMJ
TMJ pain dysfunction syndrome
Internal derangements
Osteoarthritis
Juvenile rheumatoid arthritis (Still’s disease)
Ankylosis
Tumors
Fractures
Developmental anomalies
(史迪爾氏症)

16. Summaries Knowing: Three factors implicated in TMD
Two symptoms suggestive of TMD
Imaging methods for TMD
Main pathological conditions affecting TMJ