Temporomandibular Joint Disorders

CHAPTER 94 Temporomandibular Joint Disorders



Bruce E. Rotter



Key Points



• Temporomandibular disorders is a collective term describing both intracapsular disorders and muscular disorders, or myofascial pain dysfunction.

• The general presenting complaints of temporomandibular disorders include facial pain, earache, and headache.

• The temporomandibular joint (TMJ) is a diarthrotic joint, with each joint incapable of independent movement.

• The TMJ is a ginglymoarthrodial joint, capable of both translational and rotational movement.

• TMJ dislocation occurs when a hypermobile joint translates anterior to the articular eminence and becomes locked in that position.

• The primary intracapsular disorders of the TMJ are (1) anteriorly displaced disk with reduction, (2) anteriorly displaced disk without reduction, and (3) degenerative disease.

• Anteriorly displaced disks (ADDs) are typically caused by frequent episodes of microtrauma such as clenching or grinding the teeth.

• ADDs with reduction are typically characterized by clicking or popping sounds on mouth opening. ADDs without reduction are typically characterized by a closed lock.

• Degenerative joint disease (DJD) is the most frequent abnormal condition affecting the TMJ.

• Absolute indications for TMJ surgery include treatment of neoplasms, growth abnormalities, and ankylosis of the joint.

• Relative indication for TMJ surgery is treatment of pain and dysfunction, which is refractory to nonsurgical therapy where there is confirmatory imaging evidence of pathology.

• Myofascial pain dysfunction (MPD) syndrome is a muscular disease that is believed to be induced by stress and muscular hyperactivity from parafunctional habits.

Temporomandibular disorders, or TMDs, is a collective term that has been used traditionally to describe multiple disorders. These include both intracapsular disorders, or true abnormalities of the temporomandibular joint (TMJ), and muscular disorders, or myofascial pain dysfunction syndrome (MPD). Additionally, some disorders have not been considered under the umbrella of TMD but either directly or indirectly affect the structures of the TMJ. Examples of these disorders are congenital and developmental deformities, trauma, and neoplastic disease.


The general presenting complaints of the temporomandibular disorders include facial pain, earache, and headache. Therefore it is important for otolaryngologists to be familiar with the diagnosis and treatment of these various conditions. Much of the difficulty encountered in the treatment of TMDs relates to the failure to distinguish between these disorders and other causes of head and facial pain because of the similarity of the signs and symptoms with which they present. The emphasis in this chapter is on the diagnosis of TMDs, with a subsequent discussion of what is known about the etiology of the various conditions, forming the basis for a rational approach to therapy.



Anatomy


The anatomy and function of the TMJ are unique in several ways. The TMJ is a diarthrotic joint. Because the mandible is hinged at both ends, each joint is incapable of independent movement. This is clinically important because dysfunction in one joint can adversely affect the function of the contralateral joint, producing bilateral symptoms.


Each individual joint consists of the condylar process of the mandible, which is housed within the glenoid fossa of the squamous portion of the temporal bone. The anterior wall of the glenoid fossa is formed by the articular eminence, which is the articulating counterpart to the condylar process. The articulating surfaces are lined with fibrous connective tissue and are enclosed by a fibrous capsule.


Interposed between the articulating surfaces of the TMJ is the articular disk. The disk is a unique structure that is concavo-convex on its superior surface and concave on its inferior surface, where it contacts the convex condylar head. The presence of the articular disk divides the joint into two distinct compartments and contributes to the dual action of this ginglymoarthrodial joint. The inferior compartment, or inferior joint space, allows for purely anterior and posterior rotational movement between the condyle and disk. The superior joint space allows for translational movement between the disk and the glenoid fossa and articular eminence. In addition to assisting movement within the joint, the disk acts to compensate for any incongruencies between the articular surfaces and acts as a shock absorber within the joint.1


The degree of condylar movement is governed by the limiting actions of the joint capsule, the articular disk, and the joint ligaments. The primary ligaments of the TMJ are the lateral, sphenomandibular, and stylomandibular ligaments. The relationship of the articulating components of the joints is also influenced by the presence of the teeth. When the mouth is in an open position, the degree and direction of movement of the joints are influenced by the components discussed earlier. However, when the teeth come into contact, this occlusal relationship determines the final position of the condyle with respect to the rest of the joint. This factor becomes increasingly important in individuals who exhibit occlusal disharmony or parafunctional habits.



Diseases and Disorders


The TMJ is susceptible to the same conditions that affect other joints in the body such as congenital and developmental anomalies, traumatic injuries, dislocations, internal derangements of the articular disk, ankylosis, various arthritic conditions, and, rarely, neoplastic diseases (Table 94-1). Although many of these conditions are treated in the same manner as in other joints, the previously described anatomic and functional differences of the TMJ often require some variations of therapy.



Table 94-1 Differential Diagnosis of Temporomandibular Joint Disorders

image


Congenital and Developmental Anomalies


Because the condyle has an important role in mandibular growth, congenital and developmental anomalies such as condylar agenesis, condylar hypoplasia, or condylar hyperplasia can produce severe facial deformity. It is important to diagnose and treat these conditions early in order to limit the degree of mandibular, as well as compensating, facial deformity. However, examination of the current concepts regarding the diagnosis, preparatory treatment, and surgical therapy of the dentofacial deformities is beyond the scope of the current discussion. The reader is encouraged to explore the many good publications that thoroughly discuss orthognathic surgery.2–10



Trauma


The condyloid process and, more specifically, the condylar neck is one of the most frequent sites of fracture after trauma to the mandible. Condylar or subcondylar fractures will usually produce preauricular pain and tenderness, difficulty in opening the mouth, and malocclusion. Unilateral fracture will produce jaw deviation to the affected side on attempted mouth opening. Bilateral fractures frequently produce an anterior open bite due to loss of structural support in the ascending ramus.


Treatment of condylar and subcondylar fractures varies on the basis of multiple factors. Nondisplaced fractures with minimal dysfunction may be treated with soft diet and guiding elastics. Moderate changes in occlusion or function may require short-term maxillomandibular fixation. In situations where the malposed segment is significantly displaced or interferes with jaw function, there are no occluding teeth on the involved side, or the condyloid processes are fractured bilaterally and grossly displaced, open reduction should be performed.11 Additional considerations for open reduction are the inability to perform maxillomandibular fixation and the presence of concomitant fractures in the mandible, maxilla, or midface.



Dislocation


Dislocation occurs when the hypermobile mandible becomes fixed in an open position with no or only the most posterior teeth contacting. Acute dislocation occurs when the condyle translates anterior to the articular eminence and becomes locked in that position. It is treated with manual reduction by applying downward pressure on the posterior mandible while placing upward and backward pressure on the chin. This manipulation is supplemented by the use of local anesthesia, intravenous sedation, or general anesthesia. Postreduction, the patient should restrict mandibular opening for 2 to 4 weeks. Nonsteroidal anti-inflammatory drugs (NSAIDs) should be prescribed for control of pain and inflammation.


Dislocation that is chronic can be treated by injection of a sclerosing agent into the TMJ capsule and lateral ligament to produce scarring of the stretched tissues,12 capsulorrhaphy, lateral pterygoid myotomy, temporal myotomy, or condylectomy.13 Decision as to the appropriate surgical procedure is based on the etiology, severity, and persistence of the dislocation.



Neoplasms


Primary neoplasms originating in the TMJ are extremely rare. Chondroma, osteochondroma, and osteoma are examples of benign tumors affecting the TMJ. Malignant tumors, which are even more uncommon, include fibrosarcoma, chondrosarcoma, and multiple myeloma. Direct extension of neoplasms from adjoining tissues and metastasis from distant neoplasms have been reported.


Tumors of the TMJ cause joint pain, restriction of opening, and malocclusion. Radiographic examination may demonstrate radiolucent, radiopaque or mixed lesions. Biopsy is necessary to establish a definitive diagnosis. Surgery is the treatment of choice for both benign and malignant neoplasms. Most malignant neoplasms that affect the TMJ are not radiosensitive, so radiotherapy is generally not considered.



Intracapsular Disorders


Intracapsular disorders of the TMJ include the following: (1) anterior disk displacement with reduction on opening the mouth, (2) anterior disk displacement without reduction, and (3) degenerative joint disease.


Anterior disk displacement is typically caused by trauma. This may be a single, macrotraumatic event or, more likely, frequent episodes of microtrauma that occur over a prolonged period. The majority of microtraumatic events are the parafunctional habits such as tooth clenching or grinding, which is also known as bruxism.14



Anterior Disk Displacement with Reduction


Anterior disk displacement with reduction is typically characterized by clicking or popping sounds on mouth opening (Fig. 94-1). Reciprocal or closing clicks are not consistently present. Patients who present with anterior disk displacement with reduction generally exhibit a normal range of mandibular motion. There may or may not be pain associated with mandibular movement. Multiple studies have shown that asymptomatic anterior displacement with reduction is common and often persists for years without signs of progression.14–16 It is believed that these asymptomatic, nonprogressive cases represent physiologic accommodation of the joint.17 They require no treatment. When pain is present, it is the general determinant of any functional limitation that exists. Treatment of these painful joints consists of soft diet, self-limitation of opening, NSAIDS, splint therapy, and physical therapy. Patients refractive to these conservative modes of therapy may be candidates for more invasive procedures such as arthrocentesis, arthroscopy, or open joint surgery.


image

Figure 94-1. Anterior displacement of the intra-articular disk with reduction. Jaw closed; condyle seated in fossa with disk anteriorly displaced (A). Condyle beginning translation (B). Opening of the mouth (C). A clicking or popping sound occurs as the disk returns to its normal position in relation to the condyle. Condyle fully translated; disk in normal position (D). During closure, the disk again becomes anteriorly displaced, sometimes accompanied by a second sound (reciprocal click) (E, F).


(Modified with permission from McCarty W. Diagnosis and treatment of internal derangements of the articular disc and mandibular condyle. In: Solberg WK, Clark GT, eds. Temporomandibular Joint Problems: Biologic Diagnosis and Treatment. Chicago: Quintessence; 1980.)



Anterior Disk Displacement without Reduction


Anterior disk displacement without reduction is characterized by a closed lock (Fig. 94-2). In the nonreducing joint, forward translation of the condyle on mouth opening forces the disk anteriorly, causing it to become a physical impediment to further opening. The maximum interincisal opening (MIO) is generally only 25 to 30 mm, and the mandible deviates toward the affected joint. Lateral excursive movements of the mandible are generally restricted to the contralateral side but not to the ipsilateral side. Pain is a common symptom, particularly on forced opening (beyond the MIO).


image

Figure 94-2. Anterior displacement of the intra-articular disk without reduction. Jaw closed; condyle seated in fossa with disk anteriorly displaced (A). Condyle beginning translation (B). Attempted mouth opening (C). The displaced disk acts as a barrier and prevents full translation of the condyle. Jaw closure; condyle returns to seated position in fossa (D, E).


(Modified with permission from McCarty W. Diagnosis and treatment of internal derangements of the articular disc and mandibular condyle. In: Solberg WK, Clark GT, eds. Temporomandibular Joint Problems: Biologic Diagnosis and Treatment. Chicago: Quintessence; 1980.)


Acutely displaced disks without reduction can often be successfully treated by manual manipulation of the mandible with coincident reduction of the disk. In chronic conditions, manual reduction is much less likely to lead to satisfactory reduction of the disk. This is generally due to loss of disk morphology. Patients who exhibit a chronically nonreducing disk should be initially treated with a stabilization splint in order to reduce the pressure on the retrodiskal tissues produced by masticatory and parafunctional forces. When pain is a significant component of this disorder, more aggressive or invasive procedures may be indicated.



Degenerative Joint Disease

Related posts:

  1. Voice Evaluation
  2. Central Neural Auditory Prosthesis
  3. Surgical Robotics in Otolaryngology
  4. Malignant Tumors of the Larynx

Stay updated, free articles. Join our Telegram channel
Tags:
Jun 5, 2016 | Posted by in OTOLARYNGOLOGY | Comments Off on Temporomandibular Joint Disorders

Full access? Get Clinical Tree
Get Clinical Tree app for offline access