Tempromandibular joint disorderLecture 2

جراحة الفم والاسنان -المرحلة الخامسة

رياض الطائي. د: الاستاذ المساعد فرع جراحة الفم والوجه والفكين

كلية طب الاسنان

•Temporomandibular joint (TMJ) disorders are common and affect between 25% and 40% of the population.Of those who require treatment, 95% will

require only conservative treatment.

• TMJ disorders can be classified into functional and structural disorders.• TMJ dysfunction is the most common non infective pain disorder of the orofacial region.• The treatment of TMJ disorders almost always should be nonsurgical in nature, in the first instance.

HISTORY

The history should focus on five key areas: pain, function, diet, medical history, and social history. It will give some clues as to the nature of the disorder:inside the joint (internal derangement)or outside (TMJ dysfunction syndrome).

The following should be established during the pain history

Site: Ask the patient to indicate with one finger where thepain originates. Onset: Is the onset gradual or sudden? Character: Would they characterize the pain as sharp (like aknife), dull (like an ache), or electric? Radiation: Where does the pain travel? Associated features: Is the pain associated with locking? Timing: Does the pain happen every day or most days? Howoften in a day does the pain occur? Is the pain continuous? Exacerbating or relieving features: Do pain killers alleviate symptoms?Is it exacerbated by certain functions or parafunctions (e.g., yawning, singing, eating)? Severity

EXAMINATION OF THETEMPOROMANDIBULAR JOINT

The focused examination of the TMJ is divided into four steps:(1) observation, (2) palpation,(3) auscultation,(4) examination of the occlusal function.

(distance between the maxillary and mandibular incisor edges on maximum mouth opening, which normally ranges between 42 and 55 mm), maximum protrusion, and lateral excursion(normally 7 mm for each) are measured.

Wear facets. Mandibular teeth.Wear facets. Maxillary teeth.

Tongue scalloping.Linea alba.

INVESTIGATION OF THETEMPOROMANDIBULAR JOINT

Radiological investigations include: orthopantomogram (OPG), computed tomography (CT) or cone beam CT

scan (to visualize the bones), magnetic resonance imaging (MRI) scan (for

the joint and soft tissues).

Lab investigations These include :

a full blood count (FBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RhF), antinuclear antibody (ANA), anti–double stranded deoxyribonucleic acid

(antidsDNA),

TEMPOROMANDIBULAR JOINTDYSFUNCTION SYNDROME (FUNCTIONALTEMPOROMANDIBULAR JOINT DISORDER)

TMJ dysfunction is the most common noninfectivepain disorder of the orofacial region.

Its prevalence has been suggested to increase toward the mid-40s to late 50s and then gradually fall.

There is a female predisposition, especially in the third and fourth decade of life.

It is characterized by pain within and around the TMJs andadjacent muscles of mastication. It is typically diffuse, cyclical,and worse in the morning. Patients are often anxious andcomplain about the clicking of the joint. It can be accompaniedby limitation of mouth opening, crepitus, and/or locking ofthe joint.

TMJ dysfunction is exacerbated by parafunctional habits(teeth clenching, grinding, lip biting), occlusal anomalies,trauma, and stressful life events.The history and examination will point toward a musculardisorder.

Treatment

The treatment goals are;

alleviate pain, decrease adverse joint loading, restore mandibular function, reduce or eliminat joint noise, and allow the patient to return to normal daily activities.

Treatment options include the following: homecare practices, analgesia, occlusal readjustment, splint therapy, and psychological/psychiatric intervention.

A bite raise appliance.

STRUCTURAL DISORDERS OF THETEMPOROMANDIBULAR JOINT

In structural TMJ disorders (or internal joint derangement), the pain is typically continuous, localized to the TMJ, and exacerbated by jaw function. Mechanical interference can often be observed with clicking and locking. It will often result in mandibular deviation on opening and closing initially toward the affected side, pain on loading the TMJ, as well as a decreased range of movement.

Internal joint derangement can be secondary to a range of pathological conditions including

dislocation, displacement/degeneration of the articular disc, inflammation, infection, trauma or ankylosis of the joint, condylar hyperplasia, or any neoplastic process (which can be either benign or malignant).

Temporomandibular Joint Dislocation

TMJ dislocation usually occurs in a forward direction (i.e., a position anterior and superior to the articular eminence) and can be unilateral or bilateral.

It can occur in a normal joint following trauma or in any condition where the ligaments are lax.

The patient is unable to bring their teeth into occlusion.When the dislocation is unilateral, the mandible deviates to the opposite side.

Palpation will reveal the condyle anterior to the articular eminence.

Radiographs (OPG and posteroanterior [PA]) can confirm the diagnosis

Computed tomography (CT) showing temporomandibularjoint (TMJ) dislocation.

Patients should be reassured and relocation of the joint attempted as early as possible (to avoid the effects of musclespasm). This may be facilitated by intra-articular local anesthetic or intravenous (IV) sedation (midazolam).

If the reduction is delayed, a period of inter maxillary fixation may be needed to de-function the joint following the reestablishment of its correct anatomical location.

Occasionally, reduction under general anesthetic is necessary.

Acute Trauma to the Temporomandibular Joint

Acute trauma to the joint will cause capsulitis or synovitis andwill manifest with pain, swelling around the joint, an effusionin the joint, trismus, or even a fracture.

Diagnosis will be reached through a thorough history, examination, and radiological views. During the examination of the occlusion, an open bite on the ipsilateral side of the injury is suggestive of an effusion in the joint.

An open bite on the contralateral side suggests a displaced condylar fracture with reduction of the ramus height

Treatment will focus on jaw rest, soft diet, analgesia, andtreatment of the fractures as appropriate.

Inflammatory Disorders of the Temporomandibular Joint

In inflammatory conditions, the initial changes occur in the synovial apparatus, and the cartilage is secondarily affected.

Conversely, in degenerative disease, the cartilage is primarily affected.•In rheumatoid disorder, the joint surface shows erosions and loss of joint

height, leading to collapse of the joint with contralateral open bite or anterior open bite and retrusive chin if this is bilateral.

In degenerative disease, the pain and tenderness will be localized, exacerbated by movement, and will limit mandibular movements. Patients will complain of stiffness and auscultation will reveal crepitus.

X-rays will show flattening and osteophytes of the condylar head with loss of joint space and subarticular cysts. The bony margins will proliferate and may lead to ankylosis of the joint.

Treatment includes :analgesia, rest, avoidance of overloading the jaw joints, replacement of inadequate dentures, and use of occlusal acrylic splints. Patients should be taught to use wooden spatula or a TheraBite to overcome the stiffness in the joint.

A rheumatology consultation will aid with appropriate management of a more generalized condition and disease-modifying agents may halt disease progress.

Occasionally an intra-articular steroid injection may temporarily ameliorate symptoms, but if used repeatedly, the injections can lead to the collapse of the joint.8

Meniscal (Disc) Problems

The meniscus (or disc) may be displaced, deformed or perforated.

Patients will complain of locking, clicking, and pain, especially on opening. When it is displaced, it is most commonly site anteriorly.

Initial treatment includes jaw rest, exercises, analgesia, andsplints.9 If this fails, surgery (in the form of arthroscopy, openplication/meniscopexy, or meniscectomy and so on) may beconsidered.

Infections of the Temporomandibular Joint

Infections of the TMJ are rare. either directly through an open wound or by direct spread from adjacent tissues or the blood (septicaemia).

Before the advent of antibiotics, the most common cause was middle ear infections spreading to the bone.

The causative infections are varied and include tuberculosis, typhoid fever, smallpox, scarlet fever, gonorrhea, and actinomycosis.

treatment includes drainage of any infection by means of arthrocentesis and IV antibiotics.

Ankylosis of the Temporomandibular Joint

Ankylosis can be secondary to either restriction of movementsby a pathological process within the joint (true ankylosis) or by extra-articular abnormalities (false ankylosis).

The prevalence of true ankylosis is equal between sexes with half occurring before 10 years old.Mouth opening can be severely restricted (sometimes to 5 mm) and is debilitating..

True Ankylosis of the Temporomandibular Joint

True ankylosis, which is often caused by trauma or infection,is a gradual process that declares itself over months or years. The pathological process leads to the deterioration of the disc, and the ensuing inflammatory changes lead to the formation of granulation tissue within the joint, which subsequently becomes fibrotic or ossified

Prognosis depends on the age of presentation. It is more severe in the younger patient.

The treatment depends on the nature of the union:

wooden spatula, a trismus screw a TheraBite and exercises are used to relieve fibrous union, whereas surgery is required for bony union

Computed tomography (CT) recon and axial view ofa true ankylosis of the temporomandibular joint (TMJ).

A trismus screw.A TheraBite.

False Ankylosis of the TemporomandibularJoint

False ankylosis of the TMJ may be classified into six groups: (1) myogenic (hematoma), (2) neurogenic (cerebrovascular accident [CVA]),(3) psychogenic (hysterical trismus), (4) Bone impingement (exostosis),(5) fibrous adhesions, and (6) tumors.The treatment is directed toward each particular cause.

Condylar HyperplasiaCondylar hyperplasia is defined as an uncommon abnormalityof growth of (usually) one condyle. The condyle is elongated and thin .The patient commonly presents in late puberty.

Histologically, a normal condylar architecture is seen.The etiology is poorly understood.

It presents with prognathism and rotation of the mandible to the opposite side. The contralateral masseter may hypertrophy.

Assessment includes isotope bone or positron emission tomography(PET) scanning; and if the uptake difference between sides is greater than 10%, surgical intervention by high condylar shave is considered appropriate.Subsequent deformities require orthognathic correction once growth has ceased.

Condylar hyperplasia..

Tumors of the Temporomandibular Joint

Tumors of the TMJ are rare. They can be benign or malignant.Benign tumors include osteoma chondroma, osteofibroma, osteochondroma, giant cell tumor, and hemangioma.They can be difficult to distinguish from condylar hyperplasia and will lead to facial asymmetry, an abnormal occlusion with an open bite on the affected side, a crossbite on the contralateral side, and prognathicdeviation.

•The treatment is surgical.

Three-dimensional reconstruction of a computedtomography (CT) scan showing an osteoma of the right condyle(highlighted in pink).

Malignant tumors can be either primary or secondary Primary tumors may arise from the condyle, articular fossa, capsule or disc,whereas secondary tumors may arise from direct extension or metastasis. They include chondrosarcoma, fibrosarcoma, and multiple myeloma.

They present with pain and swelling, and they may mimic TMJ dysfunction syndrome in the early stages.

The radiographic changes may resemble those of degenerative or arthritic joint disease.

The treatment includes radiotherapy and surgery.