2 Surgical anatomyThe temporomandibular joint consists of glenoid fossa on the skull base, the condyle, the articular disk separating the fossa and the tubercle, a capsule, and ligaments connected to the capsule. Both the glenoid fossa and the condyle are covered by hard, fibrotic, cartilaginous tissue, which is the thickest deep in the fossa.The condyle of the mandible is cylindrical, it becomes narrower in the posterior direction, its greatest diameter, in the mediolateral direction is about 2 cm. With a narrow neck, it passes through into the condylar process.It was earlier believed that the cartilaginous surface covering the condyle behaved as the epiphyseal plate, and that the growth centre of the mandible was situated here. It has recently been proved, however, that the growth of the capitulum is a function of the functional matrix surrouning it. This functional matrix involves the joint function of the articulation, the masticatory muscles and the soft tissues. If some restraining effect is experienced anywhere in the matrix, the condyle and also the whole of the mandible undergo a retardation of growth.
3 Surgical anatomyFrom a side view the articular disc covering the mandibular condyle is like a biconcave cap. The joint space is divided into an upper and a lower compartment. The disk consists of dense, fibrotic, cartilaginous tissue.The capsule of the articulation joint is supported by temporomandibular, stylomandibular and sphenomandibular ligaments. The last has an important role as a surgical indicator, for the maxillary artery and the auriculotemporal nerve run between the mandibular neck and the sphenomandibular ligament.The blood supply of the condyle is ensured from the superficial temporal artery and the branches of the maxillar artery
4 Diagnostic imaging procedures relating to the TMJ Many types of diseases can affect the TMJ, but the location and structure of the normal TMJ mean that it is extremely difficult to examine it with some imaging system. At present however numerous devices and methods are available that can help to get the diagnosis.
6 Functions of TMJThe TMJ is the only paired joint in the body that performs its functions in a syncronised and coordinated way.It functions are influenced by three fundamental factorsAnatomic structure of the TMJNeuromuscular mechanismDental occlusion
7 The functions of TMJAs a result of the hinge movement, the mouth opens about mm, in consequence of combination of rotating and gliding movements, the distance rises to mm.The rotation is produced by the contraction of the anterior belly of the digastric muscle and the geniohyoid muscleSliding in the anterior direction is mainly due to the lateral pterygoid muscleSliding to posterior direction depends on the functions of the deep fibers of the masseteric muscle and the posterior fibres of the temporal muscleParts are played in the closure by the paravertebral muscles and by the stylohyoid, geniohyoid and infrahyoid muscles. The most important roles are played by the masseteric muscle and the medial pterygoid and temporal muscles.
8 Temporomandibular disorders Keith classification Congenital and acquired growth disturbancesInfectionsAnkylosisTraumatic laesionsDislocation (luxation)Internal derangementDegenerative diseasesTumors
9 Congenital growth disturbances Unilateral disordersHemifacial microsomiaHemifacial microsomia is unilateral hypoplasia or aplasia of the TMJ, it is an asymmetric, progressive deficiency which relates to both soft tissues and the bony sceleton of the scull. The developmntal problem of the first and second branchial arches can cause this disease.It is classified in three groupsType I. :”minimanbible” All parts of the mandible are present and the arch is normal, but they are smallType II.: Small and anomalously arched ramus, and hypoplastic, anteriorly and medially situated condyleType III.: total unilateral absence of the condyle and ramus
10 Congenital grows disturbances Bilateral developmental anomalies of the first and second branchial archTreacher Collins syndrome (mandibulofacial dysostosis)It is characterized by a bilateral hypoplastic TMJ a short ramus and a decreased face height. This syndrome is a dominantly inherited abnormality. Its rate of occurance is 1: Clinical appearance is always bilateral. Retractions may be observes on eyelids, the lower eyelashes may be missing. The external ear is hypoplastic, hearing disturbance exists.
11 Acquired TMJ deformities Condylar hyperplasiaIt is the most frequent postnatal abnormality of TMJ . It appears in the years before puberty.It is assumed that the cause of the changes lies in the more active metabolism of the condyleTwo different growth tendencies may be distinguishedVertical The mandible grows mainly in vertical direction, which results vertically long ramus and body.Rotational Besides the enlarged condyle and vertically long ramus, the convex enlargement of the body leads to a crossbite and mouth opening deviation. The enhanced metabolism may be proved by bone scintigraphic examination.
12 InfectionsBefore the advent of antibiotics, infectious diseases of the TMJ were much common than today. Description from the 19th and 20th centuries revealed that infections of the ear and teeth often spread to the joint. The primary causes of TMJ were infectious diseases of childhood (scarlet fever, chickenpox, diphteria, etc.)Symptoms:Intense painThe most comfortable position for the patient is the opened mouthOedema, erythema above the joint, than fluctuationThe cronic state was indicated by a fistula in the region of TMJ.
13 Ankylosis There is a lot of expression, which means the disability of the movement of TMJtrismus,pseudoankylosis,ankylosis.
14 Trismus: This is an anomaly based on muscle spasm. Extracapsular process, the TMJ itself is not effected. Classic examples of the lesion are the complications that arise in the course of conduction anaesthetization. (infection, bleeding or nerve damage)Pseudoankylosis:Intraarticular cause: fibrosus ankylosis.Extraarticular cause: Include the hyperplasia of the coronoid process or its unification with the maxillary tuber or with the zygomatic bone, or a fractured zygomatic arch. It may occur as a chronic scar contracture of the temporal muscle as a consequence of irradiation or surgery.Ankylosis: This is a bony unification of the condyle and the glenoid fossa.
15 Ankylosis Etiology: Trauma Rheumatoid arthritis Infection Tumors In childhood there are a lot of vessels in the joint, which runs between the condyle and the capsule. In the event of trauma haemarthrosis will develop, which undergoes ossification.In adulthood 51% of the cases of polyarticular rheumatoid arthritis affect the TMJ. ( usually only one) In childhood, the most serious consequece of ankylosis caused by RA is the facial deformity due to the damage to the growth centre. The development of the lower third of the face is retarded and a „birdface” results.
16 Ankylosis Infections: This is now rare as a cause. Tumors: Are similary rarely observed in the TMJ
18 TreatmentIn childhood there are 4 groups in ankilosys and the treatment vaies group to group,1.On the X ray the articular gap is narrowed, but it can be followed.2.The lateral parts of the articular surface there are much more synostosis but on the medial deeper parts of the TMJ the cartilaginous surfaces are preserved and the disk may be distinguished3. There is a bridge-like synostosis between zygomatic arch and ramus of the mandible. The medial part of the capitulum is intact and able to function.4. The extent of synostosis is such that the TMJ can no longer be recognized.
19 TreatmentThe first step in treatment is surgery. The TMJ is usually exposed from preauricular incision.In cases belonging to the first two groups the TMJ can be easily recognised after exposure.After closure and postoperative period the second step is functional treatment.
20 Treatment In adulthood To avoid reossification some „interposit” is recommended between the reformed articular fossa and condyle. This may be the temporal muscle, cartilage or alloplastic material.
21 InjuriesDislocation takes place most often in the anterior direction, the condyle becomes positioned in front of the articular tubercule.Subluxation- The dislocatio is not complete, the condyle can return to the glenoid fossaRecurrant luxation - The luxation or subluxation occurs on a number of occasions but there is no psychological factor inducting compulsive movement.Habitual luxation is coused by compulsive movements.The terms luxation, distorsion and dislocation are used when the articular surfaces are totally separated from one another and the joint is fixed in this extraarticular position. It may be induced by an external ( hit, extraction) or an internal action (huge yawn, vomiting, singing, dental procedure).The direct cause of spontaneous luxation is sudden disturbance of the coordination of the muscles movement.
22 Symptoms The patient cannot close his or her mouth The mandible is elastically fixatedThe articular fossa is emptyModerate pain in the joint
23 TreatmentAcute, chronically persistent, recurrent and habitual luxation demand different modes of treatmentAcute: Reposition- The earlier the repositioning is attempted the more easily succedes. The thumbs are wrapped in gauze and placed on the occlusal surface of the mndibular molars or alveolar ridges. By pressing firmly on the molars and elevating anteriorly with simultaneous backward pressure, the condyle is relocated.Chronically persisting luxation: Reposition under general anaesthesia, when the reposition is unsuccessful, condylectomy may be consideredRecurrent: The reposition is generally easy but it is difficult to avoid repetition of the luxation. Conservative or surgical treatment.Habitual: It is difficult to know how to alter psychological component that includes the compulsive movement.
24 Internal derangement The internal derangement means intracapsular damage of the TMJ which primary arises from the incorrect movement of the articular disk together with the secondary changes of movement. The disease does not belong to developmental anomalies or to other diseases of the TMJ.
25 Internal derangementThe healthy articular disc allows the appropriate distance between the condyle and the glenoid fossaFirstly the articular disc displaces, the posterior fibers of the disc becomes loosened, the condyle will be posteriorly positioned
26 Internal derangementA further change occure if the disc streches and becomes thinner and the articular gap is reduced progressively in both posterior and anterior directionThe following step is the rupture of the disc, so the glenoid fossa and the condyle come into direct contactThe condyle slowly becomes pointed in the anterior and posterior direction and finally degenerative changes occur in the bone
27 Internal derangement Symptoms pain, deviation, repeated clicking when the mouth is opened and reciprocal clicking when closedTreatment is primary conservative and only rarely surgicalMedication: NSAID, night bite guard (bite raising appliances)
28 Degenerative diseases Osteoarthrosis (arthrosis deformans, osteoarthritis).It is a non-inflammatory degenerative diseases which mainly affects the articular surfaces but it also induces reconstruction of and changes in the bone beneath the articular surface.Symptoms: Pain, crepitation, restriction of articular movement Rheumatoid arthritisAutoimmune disease of the small periferial joints. In women it is three times common than in men. In 10-15% of the cases involve a progressive variant with articular destruction and deformities. The inflammation of the synovial membrane is carasteristic. The inflammatoric process damages the joint and the scar tissue impedes the movements.Symptoms: Intermittent pain, swelling and progressive restriction of the articular movement. Typical that the small joints of the hand and foot become involve first.
29 Other degenerative diseases GoutThis is a metabolic disease, uric acid crystals are deposited in and around the joints and these causes inflammatory symptoms. Above the joint the skin is red and swollen and in particular movement gives rise to pain.Other degenerative diseasesSpondylitis accompanied by ankylosis It differs from RA that here primarily the ligaments around the joint undergo calcification and osification.Psoriatic arthritis: symmetric polyarthritis and negative rheumatoid factorsPosttraumal arthritis: Arthritis may develop as a consequence of traumaCondyle resorption: after bilateral condyle fracture or as a consequence of otitis media
30 Degenerative diseases TreatmentConservative-pain killers-normalisation of the occlusion-interocclusal plates-sedatives-steroid intraarticularySurgical- condylectomy- arthroplasty
31 Tumors of TMJ The tumors of TMJ are very rare. These could develop from some parts of the joint or may spread from the environment of the joint.Benign tumors The condyle may be enlarged for many reasons, e.g.:acromegalia,fibrosus dysplasia,condylar hypertrophia,osteoma, osteochondroma,chondroma stb.Common typical symptoms:Slow restriction of the movement of the jointPainless swelling in the region
32 Metastases Primer tumor could be in prostata, breast, kidney, malignant melanoma,lung,pancreasetc.