1、Temporomandibular DisordersINTENDED LEARNING OUTCOMES1. Identify key clinical features of temporomandibular disorders2. Distinguish disorders of the masticatory muscles from those centred within the temporomandibular joint and from disorders of dental origin3. Distinguish those cases which may requi
2、re surgical treatment4. List possible conservative treatments and select a scheme of management for a patient with a temporomandibular disorderTMJ Anatomy Anatomical structure of TMJ -stable and flexibleCondyleGlenoid fossaArticular disc Bilaminar zone Joint capsule Ligament Lateral pterygoid muscle
3、Joint movement Rotatory movement in the lower joint space Anterior translation along the articular eminence with sliding of the disc forwardRelation of condyle and discNormal function of TMJ Many anatomy texts show the disc within the TMJ to be superior and slightly anterior to the condylar head whe
4、n the teeth are in occlusion, with the two main ridges of the disc placed one behind and one in front of the condyle. During mouth opening the condyle rotates against the disc and the disc slides forwards and downwards along the articular eminence, but the ridges on the disc remain on either side of
5、 the condylar head. This forward slide in the upper joint space is called translation. In general, much of the early part of mouth opening occurs as a hinge movement in the lower joint space and later in opening a greater part of the movement is translatory.Clinical features of TMDIntroduction The t
6、erm temporomandibular disorders (TMD) encompasses a group of conditions. The group is recognized by one or more of three principal clinical features:1. Pain associated with the temporomandibular joint (TMJ) and/or the masticatory muscles2. Noises associated with the TMJ3. Limitation of jaw movement
7、Unfortunately, each of these characteristics may take a variety of forms. This not only causes confusion for the learner but is partly responsible for the controversies concerning terminology and classification so common among the experts in the field.Pain - Clinical feature of TMD Pain of muscular
8、origin Pain from the TMJ Tenderness of the muscles or jointsPain - Clinical feature of TMD Pain of muscular origin is often described as aching, but may also be throbbing or sharp, or described as burning, stiffness, tightness, pressure, fullness or even numbness. It may be unilateral, but is the on
9、ly common pain of the head and neck experienced bilaterally. Muscular pain may be clearly localized to a trigger point centred in one muscle, or may be less well defined in distribution in the preauricular or temporal areas. Activities involving stretching or use of the masticatory muscles, such as
10、chewing, yawning, laughing or singing, usually worsen the pain. Variation over time is common, with pain often being worse in the mornings.Pain - Clinical feature of TMD Pain may also derive from the TMJ itself In this case it tends to be more localized to the joint, may be sharp, aching or throbbin
11、g, It tends to vary less during the day and is usually worsened by joint movement.Pain - Clinical feature of TMD Tenderness of the muscles or joints Sites of origin of pain are often tender to gentle palpation. Masseter and temporalis muscles are accessible to palpation over most of their surfaces.
12、Medial pterygoid can only readily be felt on the midpoint of its anterior border. Lateral pterygoid is found by passing a small finger between the maxillary tuberosity and the coronoid process of the mandible. A major difference between the sides of the face is usually of diagnostic value.Noise - Cl
13、inical feature of TMD The most common noise associated with the TMJ is clicking (or snapping, cracking, bumping or popping). Clicking TMJ is common, possibly affecting one-third of the adult population. The noise may be experienced by the sufferer only or may be audible to others, but is always asso
14、ciated with joint movement. The clinician may detect inaudible sounds by palpation or auscultation over the joints. Most people with a clicking TMJ do not suffer from their joint noise to the point that they seek help. Can clicking be regarded as an abnormality?Noise - Clinical feature of TMD Other
15、noises encountered come under the general term crepitus捻发音 and may be described by the patient as grating, grinding, crackling, rubbing and other terms. Such noises are rarely audible to others, but again may be detected by palpation or auscultation. These noises should be clearly distinguished from
16、 clicking-type noises as they almost certainly represent different aspects of disease.Limitation of jaw movement Clinical feature of TMD This may take the form of stiffness or pain on attempted mouth opening, thus restricting mobility. Where this is associated with muscular problems, it is often slo
17、w in onset and variable in severity. Locking is very sudden in onset and, if relieved, recovery is also fast. A reasonable measure of the lower limit of interincisal opening for an adult with a class 1 occlusion is 40 mm, measured between the upper and lower incisal edges. Lateral excursive and pro-
18、trusive movements may be less affected. Lower limits for these measures are approximately 7 mm.CAUSES of TMD Causes of TMD are unclear as TMD usually involves more than a single symptom and rarely has a single cause. TMD is believed to result from several factors acting together, including : jaw inj
19、uries (trauma) tooth clenching and grinding (bruxism) joint disease (arthritis) improper bite emotional unstability Overuse injury Dental Procedures Patients mouth must be opened quickly and widely in order to achieve the treament. The jaw may remain open and fixed in place for a prolonged period of
20、 time. This can lead to an overuse injury of the jaw joint. Bruxism Clenching or Grinding When you grind or clench your teeth, you can wear away the cartilage that lines the temporomandibular joint. As this happens, bone rubs on bone and creates the symptoms of TMD. This behavior may occur when you
21、are sleeping, and you might not even realize you are doing it. Grinding and clenching your teeth tends to occur more if you are stressed.Joint disease Arthritis Degenerative arthritis, such as osteoarthritis, can lead to the displacement or dislocation of the disk. This dislocated disk can lead to c
22、licking, grating or popping sounds. It can limit jaw movement and cause pain when opening and closing mouth.Occlusal factors Improper Bite If the teeth do not properly line up when biting, there may be excess stress on the chewing muscles. If this goes untreated, you may experience pain and spasms i
23、n the muscles around the jaw. In addition, the ligaments that hold the jaw in place can become overstretched and may be unable to stabilize jaw movement.Psychological factors Anxiety, tension, anger: masticatory muscle spasm bruxism Substance P increase: vasodilation and inflammation pain Psychologi
24、cal survey: TMD paranoia 偏执, depression, hysteria 癔病Comprehensive factors TMD Relevant factors : Cold, poor posture muscle spasm AnatomyClinical features Young patients of 20-30 years old Longer duration Recurrent Self-limiting Good Prognosis No ankylosisClinical manifestation Abnormal mandibular mo
25、vement Pain of muscle & TMJ Clicking & noise Other symptoms Headache - 4th symptom Ear disease - tinnitus, earache Diagnosis of TMD Basis: history, major symptoms Auxiliary examination: X-ray (Transpharyngeal) - bone changes Arthrography (upper space) - displacement, perforation, adhesion changes Jo
26、int Endoscopy - disc erosion, perforation, synovium, bone surface MRITranspharyngealArthrographyJoint EndoscopyDifferential Diagnosis1.Tumor: condylar chondrosarcoma, infratemporal fossa tumors, pterygopalatine fossa tumors, maxillary sinus cancer, parotid gland tumors2.Arthritis: purulent pain & sw
27、elling, rheumatoid multiple joint3.Ears borne diseases: the external auditory canal carbuncle, otitis media4.Cervical disease: pain unrelated to with chewing5.Dental origin: pulpitis, periodontitis, periocoronitisPAIN OF DENTAL ORIGIN In general, pain of dental origin is of relatively rapid onset (h
28、ours to days) and very well localized to the causative quadrant of the mouth or even to the tooth itself. Pulpal pain is typically worsened by thermal stimulation. Periodontal pain (apical or lateral) is associated with tenderness of (usually) one tooth to biting or to finger pressure. There are oth
29、er specific features that may be sought, such as caries, loss of vitality and radiographic signs of periodontal bone loss. Even in the case of more difficult diagnoses such as cracked teeth, local signs may be elicited.Principles of management1. Conservative therapy: symptomatic, for the cause - com
30、prehensive treatment2. Improve the physical and mental state: Psychotherapy3. Instruction: self treatment & self-protection4. Follow a reasonable treatment course: Reversible (drugs, physical therapy, occlusal appliance, rinse)Irreversible (occlusal adjustment, orthodontics) SurgeryOcclusal Applianc
31、e Therapy An occlusal appliance is a removable device, usually made of hard acrylic, which is custom fit over the occlusal surfaces of the mandibular or maxillary teeth. The physiologic basis of treatment is that the occlusal splint can effectively decrease the loading on the TMJs and reduce the neu
32、romuscular reflex activity. There are generally two types of appliances: stabilization (flat plane) and anterior repositioning.Hard acrylic full-coverage occlusal splints does not change the anterior/posterior jaw position.Stabilization appliance. The lingual ramp engages the mandibular incisors and
33、 guides the lower jaw forward. Maxillary repositioning applianceThe purpose of these appliances is to alter the structural condyle-disk-fossa relationship in an effort to decrease joint loading.Occlusal Adjustment There is a limited role for occlusal adjustment or selective grinding in the treatment
34、 of TMD. The purpose of selectively grinding the teeth is to permanently position the dentition into a better occlusion. It is an irreversible process and is best suited for the acute TMD symptoms arising from overcontoured restorations or postorthognathic surgery.Classification of TMD The classific
35、ation used in this chapter is based on that recommended by the American Academy for Orofacial Pain (McNeil 1993).Temporomandibular disorders Clinical stages： . Muscular dysfunction . Internal derangement . Degenerative diseaseMasticatory muscle disorders Types:1. Lateral pterygoid muscle hyperfuncti
36、on2. Lateral pterygoid muscle spasm3. Masticatory muscle groups spasm4. Myofascial pain dysfunctionStage 1. Lateral pterygoid muscle hyperfunction Symptoms: Clicking (articular disc is pulled excessively over the articular eminence) Too large openingsubluxation Deviation Treatment: Adjust muscle fun
37、ction（ 0.5-1% procaine 5ml, block therapy, once a day, 5-7 times as a course) Muscle training: the suprahyoid muscle groups2. Lateral pterygoid muscle spasm Symptoms: Pain when opening or chewing Dull pain, no spontaneous pain Moderate opening limitation Passive opening is larger than natural openin
38、g Unilateral mandibular movement deviation Treatment: Relieve spasms (physiotherapy, block therapy, herbs hot dressing, massage)3. Masticatory muscle groups spasm Symptoms: more common in closed muscle groups severe limited opening (Trismus), no pain Identification: opening difficulties tumors, teta
39、nus, hysteria Treatment: Relieve spasms (physiotherapy, block, herbal hot compress, massage) Mental relaxation, rest, sedation(diazepam), muscle relaxants, analgesics (aspirin) 4. Myofascial pain dysfunction Symptoms: Localized, persistent dull pain, opening pain It is predominantly a young patients
40、 condition and affects women far more commonly than men. Muscles are painful, particularly during use, often particularly so in the mornings. Specific tender spots (trigger points) may be found in individual muscles, or many muscles may be tender. The condition often develops over weeks to months bu
41、t with some degree of variation in severity over that time. Mouth opening is often restricted, but interincisal opening is rarely less than 15 mm.Trigger point A trigger point is an area of hyperirritability in a tissue that, when compressed, is locally tender, hypersensitive, and gives rise to refe
42、rred pain and tenderness. Trigger point development may be due to trauma, sustained contraction, or acute strain. When a needle penetrates this area it may cause a twitch response and referred pain.4. Myofascial pain dysfunctionTreatment: Reassurance and explanation to patientsJaw rest and soft diet
43、Sedation (diazepam), analgesic (aspirin)Tenderness - physiotherapy , block therapySecond line is the soft vinyl mouthguard (for about 6 weeks)Trigger Points and Muscle Injections Injection of local anesthetic agents without epinephrine may cause a temporary anesthesia, which enables the clinician to
44、 stretch the muscles in the affected area. A vasodilator effect of the local anesthetic may improve perfusion to the area, thus allowing harmful metabolites which may induce pain to be more readily removed by the vasculature. Internal derangement Secondary to muscle disorder Types1. Disc displacemen
45、t with reduction2. Disc displacement without reduction 3. Expansion of the joint capsule & loosening of disc attachments Stage Joint structure disordersAnterior disc displacement and deformation1. Disc displacement with reductionTwo clicks The disc is anteriorly displaced when the teeth are in occlu
46、sion. On mouth opening the disc moves back and the condyle forward relative to each other, in a sudden movement, resulting in the click and a normal relationship between the condyle and the disc. When the individual with a reducing disc displacement closes their teeth together the disc is again disp
47、laced anteriorly and lead to the click again.Diagnosis Plain radiographs are of no value in determining the position of the disc. This may be done by arthrography, arthroscopy or MRI But for almost all cases, diagnosis on clinical grounds alone is quite satisfactory.Disc displacement with reduction
48、Reduction of disc displacement on mouth openingMRI of disc displacement, mouth closed.Treatment A clicking joint may be considered normal. No treament other than reassurance and explanation can be given to the patient with symptomless click. Where disc displacement with reduction appears to be the c
49、ause of suffering, it can be treated with relatively conservative methods. The anterior repositioning appliance, occlusal splints, to interfere with parafunction may offer some help. Physiotherapy Anterior repositioning splint in place, retained with ball cleats to the lower premolars.2. Disc displa
50、cement without reduction Symptoms History of joint pain associated with the clicking, worsens over weeks to years and leads to locking, often as a sudden event. In these situations, the disc remains anteriorly displaced despite the patients best effort at opening;in other words, there is no reductio
