TEMPOROMANDIBULAR DISORDERS

Selection sources: American Association of Oral and Maxillofacial Surgeons. Parameters of Care: Clinical Practice Guidelines for Oral and Maxillofacial Surgery (AAOMS ParCare 2012). Journal of Oral and Maxillofacial Surgery. 2012, 70, 204-232

American Society of Temporomandibular Joint Surgeons. Guidelines for diagnosis and management of disorders involving the temporomandibular joint and related musculoskeletal structures. Cranio. 2003; 21(1):68-76.

Diagnostic Criteria for Temporomandibular Disorders (2014), Complete DC/TMD Instrument Set, International RDC/TMD Consortium, http://www.rdc-tmdinternational.org/TMDAssessmentDiagnosis/DCTMD.aspx

Peck C, J Goulet, F Lobezzoo et al.Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders. Journal of Oral Rehabilitation. 2014, 41, 2-23

Schiffman E, R Ohrbach, E Truelove et al. Diagnostic Criteria for Temporomandibular Disorders (DC/ TMD) for Clinical and Research Applications: recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group. J Oral Facial Pain Headache, 2014, 28, 6–27

Scrivani S, D Keith, L Kaban. Temporomandibular Disorders. N Engl J Med, 2008; 359, 2693-2705

The American Academy of Orofacial Pain. Orofacial pain: guidelines for assessment, diagnosis and management, 5th ed. Chicago (IL): Quintessence Publishing Co, Inc.; 2013.

Introduction

• The American Academy for Dental Research recognizes thattemporomandibular disorders (TMDs) encompass a group ofmusculoskeletal and neuromuscular conditions that involve thetemporomandibular joints (TMJs), the masticatory muscles, and allassociated tissues.

• The signs and symptoms associated with these disorders are diverse, andmay include difficulties with chewing, speaking, and other orofacialfunctions. They also are frequently associated with acute or persistentpain, and the patients often suffer from other painful disorders(comorbidities).

• The chronic forms of TMD pain may lead to absence from or impairment ofwork or social interactions, resulting in an overall reduction in the qualityof life.

• TMD is a pathology involving any or all of the following anatomicalstructures: the temporomandibular joint, muscles /ligaments/, tendonssurrounding the joint, structures surrounding the joint such as the ears,neck, cervical spine, teeth, and face.

• Although TMJ technically refers to the joint itself, any pathology or disorderrelated to this region is often medically referred to as TMJ rather thanTMD.

• TMJ is defined as any disease impacting the jaw joint, or the musclesresponsible for dental occlusion and jaw mobility.

• Problems arise when an imbalance occurs within any of the structures inand around the temporomandibular joint.

• The typical TMJ disorders are specifically defined as: pain dysfunctionsyndrome, arthritis, dysfunction due to trauma, or internalderangement involving the articular disk.

• All of these disorders typically present with the same spectrum ofsymptoms and respond in the same manner to treatment.

• Patients with TMJ often present with symptoms related to themuscles of mastication and structures involved in joining themandible to the skull (the temporal bone).

• Many of these symptoms occur as a result of the physical stress onthe structures around the joint.

0 to 10 10 to 20 20 to 30 30 to 40 40 to 50 50 to 60 60 to 70 70 to 80 80 to 90

Age distribution of TMD in USAUniversity of California, San Francisco, Center for TMD and Orofacial Pain,

1993 – 1995

Anatomical considerations

• The temporomandibular joint(TMJ) is composed of thetemporal bone and themandible, as well as aspecialized dense fibrousstructure, the articular disk,several ligaments, and numerousassociated muscles.

• The TMJ is a compound jointthat can be classified byanatomic type as well as byfunction.

TMJ AnatomyThe Temporomandibular joint(s) is one of the

most complex joints of the human anatomy. Likemany of the joints in the body, it is a synovialjoint surrounded by synovial fluid for nutritionand lubrication. It is made up of a superior andinferior compartment created by the disk ormeniscus within the joint cavity.

The joint itself is comprised of 3 mainstructures: the articular or mandibular fossa ofthe temporal bone, the mandibular condyle,and an articular disk.

The articular fibro-cartilaginous disk islocated in between the condyle of the mandibleand the mandibular fossa of the temporal bone.

In the healthy temporomandibular joint, thedisk acts to absorb stress within the joint, aswell as improve fluidity of jaw movement.

TMJ Meniscal Anatomy

•Oval-shaped fibro-cartilaginous articular disk(meniscus) between theosseous components of thejoint.

•The central, intermediateportion of the disk is thin whilethe anterior and posterioraspects, or bands, are thicker.

•The bi-laminar zone attachesto the posterior disc assists thehead of the condyle in movingforward.

Ligaments• Temporomandibular

ligament

• Stylomandibularligament

• Sphenomandibularligament

Anatomically the TMJ is a di-arthrodial joint, which is a discontinuous articulation of two bones permitting freedom of movement that is dictated by associated muscles and limited by ligaments.

• Its fibrous connective tissue capsule is well innervated and well vascularized andtightly attached to the bones at the edges of their articulating surfaces. It is also asynovial joint, lined on its inner aspect by a synovial membrane, which secretessynovial fluid.

• The fluid acts as a joint lubricant and supplies the metabolic and nutritional needs ofthe non-vascularized internal joint structures.

Cartilage and Synovium

Lining the inner aspect of all synovial joints,including the TMJ, are two types of tissue:articular cartilage and synovium.

The space bound by these two structures istermed the synovial cavity, which is filled withsynovial fluid. The articular surfaces of both thetemporal bone and the condyle are coveredwith dense articular fibrocartilage, a fibrousconnective tissue.

This fibrocartilage covering has the capacity toregenerate and to remodel under functionalstresses. Deep to the fibrocartilage, particularlyon the condyle, is a proliferative zone of cellsthat may develop into either cartilaginous orosseous tissue. Most change resulting fromfunction is seen in this layer.

Synovial fluid is considered an ultrafiltrate of plasma. It contains a high concentration of hyaluronic acid, which is thought to be responsible for the fluid’s high viscosity.

• The proteins found in synovial fluid are identical to plasma proteins.

• Functions of the synovial fluid include lubrication of the joint, phagocytosis ofparticulate debris, and nourishment of the articular cartilage.

• Joint lubrication is a complex function related to the viscosity of synovial fluid andto the ability of articular cartilage to allow the free passage of water within thepores of its glycosaminoglycan matrix.

The Articular Disk

The articular disk is composed of densefibrous connective tissue and isnonvascularized and noninnervated, anadaptation that allow pressure.

Anatomically the disk can be divided intothree general regions as viewed from thelateral perspective: the anterior band, thecentral intermediate zone, and the posteriorband.

The thickness of the disk appears to becorrelated with the prominence of theeminence.

The Articular Disk

The intermediate zone is thinnest and isgenerally the area of function between themandibular condyle and the temporalbone. Despite the designation of separateportions of the articular disk, it is in fact ahomogeneous tissue and the bands do notconsist of specific anatomic structures.

The disk is flexible and adapts to functionaldemands of the articular surfaces. Thearticular disk is attached to the capsularligament anteriorly, posteriorly, medially,and laterally. Some fibers of the superiorhead of the lateral pterygoid muscle inserton the disk at its medial aspect, apparentlyserving to stabilize the disk to themandibular condyle during function.

Articular disc, fossa, and condyle (anterior view). The disc adapts to the morphology of the fossa and the condyle. LP, lateral pole; MP, medial pole.

Lateral view and (B) diagram showing theanatomic components: RT, retrodiscal tissues;SRL, superior retrodiscal lamina (elastic); IRL,inferior retrodiscal lamina (collagenous); ACL,anterior capsular ligament collagenous); SLPand ILP, superior and inferior lateral pterygoidmuscles; AS, articular surface; SC and IC,superior and inferior joint cavity; the discal(collateral) ligament has not been drawn.

Musculature

• All muscles attached to the mandible influence its movement to somedegree. Only the four large muscles that attach to the ramus of themandible are considered the muscles of mastication; however, a totalof 12 muscles actually influence mandibular motion, all of which arebilateral.

• Muscle pairs may function together for symmetric movements orunilaterally for asymmetric movement. For example, contraction ofboth lateral pterygoid muscles results in protrusion and depression ofthe mandible without deviation, whereas contraction of one of thelateral pterygoid muscles results in protrusion and opening withdeviation to the opposite side.

Musculature

• Muscles influencing mandibular motion may be divided into two groups byanatomic position. Attaching primarily to the ramus and condylar neck ofthe mandible is the supramandibular muscle group, consisting of thetemporalis, masseter, medial pterygoid, and lateral pterygoid muscles. Thisgroup functions predominantly as the elevators of the mandible.

• The lateral pterygoid does have a depressor function as well. Attaching tothe body and symphyseal area of the mandible and to the hyoid bone is theinframandibular group, which functions as the depressors of the mandible.The inframandibular group includes the four suprahyoid muscles (digastric,geniohyoid, mylohyoid, and stylohyoid) and the four infrahyoid muscles(sternohyoid, omohyoid, sternothyroid, and thyrohyoid).

Musculature

• The suprahyoid muscles attach to both the hyoid bone and themandible and serve to depress the mandible when the hyoid bone isfixed in place.

• They also elevate the hyoid bone when the mandible is fixed in place.

• The infrahyoid muscles serve to fix the hyoid bone during depressivemovements of the mandible.

TMJ Biomechanics

• The TMJ allows the jaw to open, close, protrude, retract, and deviate laterally.

• Normal opening - 35-45 mm

• Two motions:• First 20 mm of motion is rotation. The mandible and meniscus move anteriorly together

beneath the articular eminence while opening or closing.

• Second motion is translation, which slides the jaw further forward or from side to side.

TMJ Biomechanics

• Unlike many other joints, however, this bi-articular, hinge-type joint allowsfor rotation or pivoting movement, in addition to translation or slidingmovements bilaterally within the jaw. In the upper compartment or cavity,translation, gliding or sliding movement occurs; therefore the rotation, orhinge movement takes place within the lower cavity. The rotation occursfirst from the beginning to the midpoint of movement range. The lateralpyterygoid (upper head) muscle assists with this motion by pulling the diskanteriorly preparing for the rotation of the condyle. The rotation can thenoccur between the disks and the two condylar heads. This is where the diskbecomes important in allowing for congruency and lubrication within thejoint. The second type of movement at the TMJ is the gliding component. Itoccurs as a result of translational movement of the condyle and disk alongthe articular eminence of the temporal bone. Both rotation and glidingmust occur for the jaw to fully open and close efficiently.

Panoramic X-ray for TMJ assessment

Causes

• Trauma

• Excessive stress

• Arthritis of the TMJ

• Whiplash injury

• Postural abnormality

• Ligamentous laxity

• Psychosocial distress (stresses)

• Bruxism (teeth grinding)

• Unaligned teeth

• Congenital Jaw abnormalities

• Prolonged mouth breathing

• Thumb sucking

Additional Symptoms

People with temporomandibular dysfunctions frequently report symptoms of depression, affected sleep quality, and a decrease in energy.

It may also interfere with personal relationships and normal social activities.

Etiologies -potential causes for TMD

These include: Dental malocclusion or orthodontic braces; ProlongedStress and or tension; Grinding or clinching of the teeth; Poor posture,i.e. forward head while working all day or looking at a computer forlong periods of time; Strain of face and neck muscles; Having themouth open for long periods of time; Poor diet, eating habits, longterm gum chewing; Lack of sleep; TMJ disk dislocation; trauma or ablow to the face; repeated traumas, like clenching the teeth orexcessive gum chewing, nail biting or cradling a phone between yourshoulder and the side of the head; constant muscle spasm of jawmusculature; developmental abnormalities of bones, joints, and/ormuscles.

Main symptoms and complaints :

• Biting or chewing difficulty or discomfort; Clicking, popping, or gratingsound when opening or closing the mouth; Bruxism (grinding of theteeth); Dull, aching pain in the face in and around joint; Ear ache;Frequent headaches; Point tenderness of the jaw; Hypertonicity ofthe jaw muscles; Reduced ability to open or close the mouth;Excessive movement of the jaw upon opening or closing the jaw;Neck or back pain; "trigger points" (due to contracted muscles in jaw,head, and neck); Changes of dental structure; Altered occlusionmechanics - cross-bite, under-bite, over-bite

Signs/Symptoms

• Facial pains/Muscle spasms

• Pain/tenderness in the muscles of mastication and joint

• Joint sounds (popping, clicking)

• Limited jaw motion

• Jaw locking open or closed

• Headaches

• Inability to comfortably open/close mouth

• Dizziness

• Ringing in the ears

• Visual disturbances

• Deviation of jaw to one side

• Teeth grinding

• Abnormal swallowing

RDC/TMD Research Diagnostic Criteria for Temporomandibular Disorders - Dworkin и LeResche, 1992

TMD Research Diagnostic Criteria

• A subject can be allocated one muscle disorder at the most. Inaddition, each joint can be assigned one diagnosis from each group (IIand III). Therefore, a number of diagnoses can be given to one personat one time, ranging from 0 (no TMD diagnosis) up to 5.

• However, it is uncommon to assign more than 3 diagnoses to onepatient.

• A fuller written description is contained in Dworkin’s original articleand algorithms allowing the diagnosis to be made from componentsof the RDC history and examination.

Trigger points

Ф

Clinical examination of myofascial painful trigger points –

flat and volumetric palpation

Tekscan

Myotronics K7

Anterior disk displacement

Advanced osteoarthritis

Anteriorly displaced and deformed disk with cortical osteofit and sclerosis

Completely destroyed articulatory disk

Osteoarthrosis of the left joint and myofascial pain syndrome. The 3D CT scans showdegenerative changes in the left joint.

Degenerative joint disease. Osteoarthrosis, osteoarthritis. Typical deviation of the jaw in the direction of the damaged hypomobile joint. A pronounced pain symptomatology in the damaged joint and the homolateral musculature.

Osteoarthrosis and myofascial pain syndrome in the contralateral musculature The digitalorthomantomogram shows degenerative-arthrosis changes in the right joint. Unilateralarthrosis and hypomobility of the right joint, compensatory hypermobility of thecontralateral joint with pronounced myofascial pain symptoms of the contralateralmasticatory and cervical muscles

3-D color reconstruction of hyperplastic right condyle

3-D color reconstruction of hyperplastic right condyle

A case of systemic arthropathy - rheumatoid arthritis. Severe bilateralpain symptoms

Bilateral erosions of both condyles

Subluxation. Profile radiographs show bilateral subluxation of temporomandibular joints

Manual extension of the joint.Luxation repositioning, non-reduction disc displacement.

Unilateral muscular hypertrophy in unilateral chewing

Treatment principles:

According to AADR TMD Policy Statement Revision 2010 it is stronglyrecommended that, unless there are specific and justifiable indications tothe contrary, treatment of TMD patients initially should be based on the useof conservative, reversible and evidence-based therapeutic modalities.Studies of the natural history of many TMDs suggest that they tend toimprove or resolve over time.While no specific therapies have been proven to be uniformly effective,many of the conservative modalities have proven to be at least as effective inproviding symptomatic relief as most forms of invasive treatment.Because those modalities do not produce irreversible changes, they presentmuch less risk of producing harm. Professional treatment should beaugmented with a home care program, in which patients are taught abouttheir disorder and how to manage their symptoms.

TMD Treatment

Conservative treatment commonly includes NSAID's or low-dose try-cyclic medication for pain; antidepressants; muscle relaxants; Restingthe joint; Posture training and education; jaw relaxation techniques;stress relief techniques; trigger point therapy/ischemic pressure formuscle spasm and pain;Education or purchase of maxillomandibularappliances(dental/bite guard, splint, or night guard, to prevent teethgrinding and correct bite); Avoidance of jaw movement at extremeranges; Avoidance of chewy/sticky candy and chewing gum.

Occlusal splints

Occlusal splints

Synthes Titanium Mandibular Condylar Endoprosthesis