Temporomandibular Joint PDF

5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad Temporomandibular joint Introduction: The temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilate...

5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad Temporomandibular joint Introduction: The temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that its name is derived. This joint is unique in that it is a bilateral joint that functions as one unit. Since the TMJ is connected to the mandible, the right and left joints must function together and therefore are not independent of each other Anatomy ( short notes ) Capsule and articular disc. The capsule is a dense fibrous membrane that surrounds the joint and incorporates the articular eminence. It attaches to the articular eminence, the articular disc and the neck of the mandibular condyle. The unique feature of the temporomandibular joint is the articular disc. The disc is composed of dense fibrocartilagenous tissue that is positioned between the head of the mandibular condyle and the glenoid fossa of the temporal bone. The temporomandibular joints are one of the few synovial joints in the human body with an articular disc,( another being the sternoclavicular joint). The disc divides each joint into two compartments, the lower and upper compartments. These two compartments are synovial cavities, which consists of an upper and a lower synovial cavity. The synovial membrane lining the joint capsule produces the synovial fluid that fills these cavities. The central area of the disc is avascular and lacks innervation, thus getting its nutrients from the surrounding synovial fluid. In contrast, the posterior ligament and the surrounding capsules along has both blood vessels and nerves. Few cells are present, but fibroblasts and white blood cells are among these. The central area is also thinner but of denser consistency than the peripheral region, 1  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad which is thicker but has a more cushioned consistency. The synovial fluid in the synovial cavities provides the nutrition for the avascular central area of the disc. With age, the entire disc thins and may undergo addition of cartilage in the central part, changes that may lead to impaired movement of the joint. The articular disc is a fibrous extension of the capsule in between the two bones of the joint. The disc functions as articular surfaces against both the temporal bone and the condyles and divides the joint into two sections,( as already described). It is biconcave in structure and attaches to the condyle medially and laterally. The anterior portion of the disc splits in the vertical dimension, coincident with the insertion of the superior head of the lateral pterygoid. The posterior portion also splits in the vertical dimension, and the area between the split continues posteriorly and is referred to as the retrodiscal tissue. Unlike the disc itself, this piece of connective tissue is vascular and innervated, and in some cases of anterior disc displacement, the pain felt during movement of the mandible is due to the condyle compressing this area against the articular surface of the temporal bone. Ligaments There are three ligaments associated with the temporomandibular joints: one major and two minor ligaments. These ligaments are important in that they define the border movements, or in other words, the farthest extents of movements, of the mandible. Movements of the mandible made past the extents functionally allowed by the muscular attachments will result in painful stimuli, and thus, movements past these more limited borders are rarely achieved in normal function. The major ligament, the temporomandibular ligament, is actually the thickened lateral portion of the capsule, and it has two parts: an outer oblique portion (OOP) and an inner horizontal portion (IHP). The base of this triangular ligament is attached to the zygomatic process of the temporal bone and the 2  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad articular tubercle; its apex is fixed to the lateral side of the neck of the mandible. This ligament prevents the excessive retraction or moving backward of the mandible, a situation that might lead to problems with the joint. The two minor ligaments, the stylomandibular and sphenomandibular ligaments are accessory and are not directly attached to any part of the joint. The movement of the TMJ Rotational movement—this is the initial movement of the jaw when the mouth opens. The upper joint compartment formed by the articular disc and the temporal bone is involved in translational movement—this is the secondary gliding motion of the jaw as it is opened widely. The part of the mandible which mates to the under-surface of the disc is the condyle and the part of the temporal bone which mates to the upper surface of the disk is the articular fossa or glenoid fossa or mandibular fossa. Etiological factors of the TMJ disorder. The causes of temporomandibular disorders are complex and multifactorial. There are numerous factors that can contribute to temporomandibular disorders. Factors that increase the risk of temporomandibular disorders are called “Predisposing factors” and those causing the onset of temporomandibular disorders are called “Initiating factors” and factors that interfere with healing or enhance the progression of temporomandibular disorder are called “Perpetuating factors.” The most common factors include bruxism and orthopedic instability, macrotrauma and microtrauma,other factors like poor health and nutrition, joint laxity and exogenous estrogen.and psychosocial factors like stress. Occlusion is the first and probably the most discussed etiologic factor of temporomandibular disorders. overclosure was the cause of symptoms in temporomandibular disorders. Because of this reason the dentists adopted bite 3  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad raising dental procedures as the treatment for temporomandibular disorder, which however sometimes failed to give expected relief to the patients. The role of occlusion in the development of temporomandibular joint disorders is controversial. Today its role is widely considered as contributing by initiating, perpetuating or predisposing of temporomandibular joint disorders.Initiating factors lead to the onset of the symptoms and are related primarily to trauma or adverse loading of the masticatory system. In the perpetuating factors the following may be included: a. Behavioral factors (grinding, clenching and abnormal head posture) b. Social factors (could effect perception and influence of learned response to pain) c. Emotional factors (depression and anxiety) Not all patients need psychological evaluation and management; however, many can be helped by what dentistry cannot provide. the concern is that the psychological component of this debilitating condition is too frequently overlooked or ignored.( Perhaps ignoring the psychological component is what leads to the frustration and difficulty in managing the TMJ/TMD patient..) d. Cognitive factors (negative thoughts and attitudes which can make resolution of the illness more difficult). Predisposing factors are pathophysiologic, psychological or structural processes that alter the masticatory system sufficiently to increase the risk of development of temporomandibular disorders while the main occlusion effect include. a. Open bite b. Overjet greater than 6-7 mm c. Retruded contact position/intercuspal position with sliding greater than 4 mm d. Unilateral lingual cross-bite 4  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad e. Five or more missing posterior teeth f. Faulty restorations and ill-fitting prosthesis. Iatrogenic injuries can act as both initiating as well as predisposing factors. This can occur during any dental procedure in which there is prolonged opening like orthodontic treatment, single-sitting root canal treatment or because of factors like relapse which causes a functional imbalance between the temporomandibular joints, muscles and occlusion of the mandible and the clinical symptoms of the TMJ In the context of association between TMD and systemic diseases it has been shown that infectious arthritis, traumatic arthritis, osteoarthritis, rheumatoid arthritis and secondary degenerative arthritis can affect the TMJ. Symptoms Signs and symptoms of TMJ disorders may include: Pain or tenderness of the jaw Pain in one or both of the temporomandibular joints Aching pain in and around the ear Difficulty chewing or pain while chewing Aching facial pain Locking of the joint, making it difficult to open or close the mouth TMJ disorders can also cause a clicking sound or grating sensation when open the mouth or chew. But if there's no pain or limitation of movement associated with the jaw clicking, don't need treatment for a TMJ disorder. The jaw is controlled the temporomandibular joint (TMJ). TMJ can become tense or locked due to stress, misalignment, and teeth grinding. A locked jaw is 5  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad a painful condition that can often cause other problems like headaches and neck or face soreness. Trismus, also called lockjaw, is reduced opening of the jaws (limited jaw range of motion). It may be caused by spasm of the muscles of mastication or a variety of other causes usually temporary trismus occurs much more frequently than permanent trismus. It is known to interfere with eating, speaking, and maintaining proper oral hygiene. This interference, specifically with the patient's ability to swallow properly, results in an increased risk of aspiration. In some instances, trismus presents with altered facial appearance. The condition may be distressing and painful for the patient. Examination and treatments requiring access to the oral cavity can be limited, or in some cases impossible, due to the nature of the condition itself Clinical Significance 1. The differentiation of pain originating within the joint from that coming from extraarticular structures is essential to successful treatment. The distinction cannot always be made from the history, however, and both intra- and extraarticular structures may be involved simultaneously. The patient with stress-related MPDS usually complains of constant, dull pain that may or may not be exacerbated by mastication or mandibular movement and relieved by jaw rest. Quite often, this pain is worse in the morning, if related to nighttime parafunctional clenching or bruxism. To be more clarify for example The patient with intraarticular TMJ pain due to arthritis has the pain relieved by jaw rest and may be pain free except when moving the mandible or masticating solid food. Unfortunately, intraarticular TMJ 6  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad disease often involves the masticatory muscles secondarily so that both types of pain (intra- and extraarticular) are experienced simultaneously by the patient. 2. Joint noise. during function is highly suggestive of intraarticular disease. Grinding or crepitus often indicates an arthritic or other degenerative process and is caused by contact of roughened bony surfaces during function. Clicking or popping in the joint is usually associated with displacement of the fibrocartilaginous disk (meniscus) that separates the joint into upper and lower compartments. the followings facts should be understand by the examiner of the TMJ Jaw popping without accompanying pain is not typically a cause for concern. If certain health conditions underlie the popping, medical intervention may be needed. The cause of jaw popping is not completely understood. Jaw popping can often be treated at home, especially if there is no pain or other symptoms. However, anyone of any age or gender can experience jaw popping, which may be linked to behaviors such as: grinding the teeth chewing gum regularly or excessively nail-biting clenching the jaw biting the inside of the cheek or lip Also, several medical conditions can lead to jaw popping, including Arthritis is a disease of the joints. Two of the most common forms of arthritis are rheumatoid arthritis and osteoarthritis, both of which can result in cartilage damage in the TMJ. as a result, destruction of the TMJ cartilage tissue can make jaw movements difficult and can cause a popping sound and clicking sensation in the joint. 7  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad. 3. Limitation of mandibular opening may be due to reflex spasm of masticatory muscles secondary to MPDS, other reason fibrous or bony ankylosis of the joint, or fracture of the mandibular condyle, or to total anterior displacement of the joint meniscus that blocks normal forward movement of the mandibular condyle. In physical examination for temporomandibular disorders, measurement and recording of mandibular movements should be completed for opening, and lateral and protrusive movements. The quality and symmetry of jaw movement should be noted and diagrammed. During the clinical examination a significant differences in the amplitude of jaw opening between TMD patients and control subjects. compared active maximum mouth opening, and temporomandibular stiffness values of temporomandibular disorder patient subgroups and a control group. The temporomandibular disorder patient subgroups consisted of myogenous pain patients and arthrogenous pain patients with a "closed lock" and arthrogenous pain patients without a "closed lock." Both myogenous patients and the "closed lock" patients showed great differences for all parameters 8  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad 4. Hyper mobility can result in excessive anterior movement of the jaw and the articular disc. This will result in deviation of the jaw away from the affected side. There are usually some clicking sounds in the TMJ and there may or may not be pain. Hyper mobility may be related to connective tissue disorders such as Marfan syndrome or conditions such as Down’s syndrome and cerebral palsy. Long term hyper mobility can cause the articular disc to elongate and degenerate. The disc can then fail to reduce on closing, causing the TMJ to become stuck in an open position (Open Lock). This can often occur after opening the mouth to an extreme position, such as or yawning or after a prolonged dental procedure The diagnosis of TMJ DIAGNOSIS There are different clinical protocols used to establish TMD diagnoses but the Research Diagnostic Criteria for TMD (RDC/TMD) most commonly used. The diagnosis of TMD is based largely on history and physical examination findings. The symptoms of TMD are often associated with jaw movement (e.g., opening and closing the mouth, chewing) and pain in the preauricular, masseter, or temple region. Another source of orofacial pain should be suspected if pain is not affected by jaw movement. Adventitious sounds of the jaw (e.g., clicking, popping, grating, crepitus) may occur with TMD.Other symptoms may include dizziness or neck, eye, arm, or back pain. Chronic TMD is defined by pain of more than three months' duration. Physical examination findings that support the diagnosis of TMD may include—but are not limited to—abnormal mandibular movement, decreased 9  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad range of motion, tenderness of masticatory muscles, pain with dynamic loading, signs of bruxism, and neck or shoulder muscle tenderness. Clinicians should assess for malocclusion (e.g., acquired edentulism, hemifacial asymmetries, restorative occlusal rehabilitation), which can contribute to the manifestation of TMD. Cranial nerve abnormalities should not be attributed to TMD. A clicking, crepitus, or locking of the TMJ may accompany joint dysfunction. A single click during opening of the mouth may be associated with an anterior disk displacement. A second click during closure of the mouth results in recapture of the displaced disk; this condition is referred to as disk displacement with reduction. When disk displacement progresses and the patient is unable to fully open the mouth (i.e., the disk is blocking translation of the condyle), this condition is referred to as closed lock. Crepitus is related to articular surface disruption, which often occurs in patients with osteoarthritis. Reproducible tenderness to palpation of the TMJ is suggestive of intra-articular derangement. Tenderness of the masseter, temporalis, and surrounding neck muscles may distinguish myalgia, myofascial trigger points, or referred pain syndrome. Deviation of the mandible toward the affected side during mouth opening may indicate anterior articular disk displacement INTERNAL DERANGEMENTS OF THE TMJ The most common form of internal temporomandibular joint derangement is anterior misalignment or displacement of the articular disk above the condyle. Symptoms are localized joint pain and popping on jaw movement. Diagnosis is based on history and physical examinatio The general principle in the internal derangement of the TMJ can be clarify through the following :  5th grade oral medicine lecture 19 Mohammed mahdi M.Sc. oral medicine reference Prof. Dr. Fawaz Al-Aswad Abnormal jaw mechanics can be due to congenital or acquired asymmetries or to the sequelae of trauma or arthritis. If the disk remains anterior, the derangement is said to be without reduction. Restricted jaw opening (locked jaw) and pain in the ear and around the temporomandibular joint may result. If at some point in the joint’s excursion the disk returns to the head of the condyle, the derangement is said to be with reduction. Disc displacement with reduction In disc displacement with reduction, the articular disc has displaced anterior to the condylar head. It may also be displaced medially or laterally. The posterior most border of the disc is anterior to the 11:30 position of the condylar head. The disc remains in this position as long as the mouth is closed. When the mouth is opened, the disc is re-situated on the condylar head. The movement of the disc onto and off the condylar head may result in a clicking, snapping, and/or popping sound. This sound does not occur with every mandibular movement. Rather, it should be heard by the patient at least once in the last 30 days and by the examining dentist during at least a third of the mandibular movements. Because the disc reduces during condylar translation, range of motion is not limited. However, movements may not be as smooth as a normal TMJ because of the momentary sliding of the condyle on and off of the disc. Disc displacement with reduction with intermittent locking This condition is identical to disc displacement with reduction, with the additional feature of intermittent limited mandibular opening on the occasions that the disc does not reduce. Disc displacement without reduction with limited opening This diagnosis is given when the articular disc consistently does not reduce, resulting in limiting opening. Limited opening is defined as