Hi, I'm Tania Kushner. Today I'm going to demonstrate a simple screening evaluation that can be implemented to record a patient's baseline TMJ and muscular function. Dentists providing oral appliance therapy should become familiar with head and neck anatomy and function, including the temporomandibular joint and muscles of mastication. Many patients presented for oral appliance therapy have pre-existing structural or functional abnormalities in the temporomandibular joints and muscles of mandibular movement. Furthermore, oral appliance treatment positioning can impact the same structures. Implementing a pretreatment evaluation will allow a dental sleep medicine clinician to record a patient's baseline TMJ and muscular function, in addition to making patient-specific recommendations regarding treatment options based on those findings. The evaluation consists of two components, the patient's history and the physical examination. The history can be obtained using a number of different questionnaires. Today I will utilize the Diagnostic Criteria for TMD Symptoms questionnaire. This particular questionnaire records current and historical TMJ symptoms. It is important to review the questionnaire results with the patient. This allows both patient and clinician an opportunity to discuss pre-existing or asymptomatic conditions that might lead to an increased chance of side effects. The TMJ physical examination consists of four components, mandibular range of motion, TMJ sounds, TMJ palpation, and muscle palpation. We will begin with a brief overview of the anatomy of the temporomandibular joint. The TMJ is formed by the mandibular condyle and the mandibular fossa of the temporal bone. A third component of the joint is the articular disc, which separates the two bones from direct articulation and divides the joint into superior and inferior compartments. This allows the complex movements of the joint, namely rotation and translation. The disc is avascular and composed of dense, fibrous connective tissue. It is attached to the mandibular condyle with discal ligaments on both lateral and medial poles. Posteriorly, the disc is attached to the retrodiscal ligament, which is a highly vascularized and innervated loose connective tissue. The TMJ is a synovial joint, and the movement of the healthy joint should be smooth, without sounds, restrictions, or dyskinesia. Before proceeding with the examination, it is best to establish rapport with the patient by explaining the procedure and encouraging feedback. As a part of my examination today, I will evaluate the health of your jaw joints and muscles. I will have you open your jaw wide, move it side to side, and forward. I will also take some measurements and check if there's any tenderness in muscles or joints. As we go through these motions, please let me know if you experience any pain or discomfort. Before asking the patient to move their jaw, we will gather baseline measurements with the teeth fully occluded. First, observe the patient's dental midlines and record if the upper and lower dental midlines are aligned or if there is a midline discrepancy. Any discrepancy is measured with the ruler and should be recorded in millimeters. Go ahead and open for me and bite down. This patient's midlines are aligned. Next, record the patient's overjet and overbite. Overjet is the horizontal overlap between the upper and the lower incisors. And go ahead and bite down again. This patient's overjet is two millimeters. Overbite is the vertical overlap between the incisal edges. Have the patient bite together, mark the position of maxillary incisal edge, have the patient open, and measure the distance to the mandibular incisal edge. Go ahead and open and close. And open again. This patient's overbite is four millimeters. Next, we proceed to the widest comfortable opening. It is important to observe the mandibular path of opening and record any deviation or deflection of the mandible. A deviation is an opening pathway that deflects right or left but returns to the midline at maximum opening. A deflection is an opening pathway that moves right or left and does not return to the midline at the maximum opening. To measure opening, instruct the patient to open to the widest comfortable position without any pain. Measure the interincisal distance and add the overbite measurement. Go ahead and open as wide as you can comfortably. And close. This patient has an interincisal opening measurement of 50 millimeters. When added to the overbite, we have a maximum comfortable opening of 54 millimeters. After recording lateral movements, position the ruler to align between the lower central incisors. Then instruct the patient to move the mandible to the right and to the left. Then record the distance in millimeters. To account for any midline discrepancy, add or subtract the difference. Go ahead and open and bite down. Open slightly and move your jaw to the right as far as you can comfortably. And now move to the left. This patient has the right lateral movement of measuring 10 millimeters with the left lateral movement measuring 10 millimeters. Finally, instruct the patient to protrude the mandible. Observe and record deflection or deviation if present. In this instance, I'll record the maximum protrusion from upper to the lower incisor tips, then add the previously measured overjet. Move your jaw forward as far as you can. This patient has a protrusive measurement of 5 millimeters. Adding to the overjet, there is a total of 7 millimeters. Now that we have examined the movements of the mandible, we will evaluate and record joint sounds that occur with the movements. They can be muffled and discovered mostly by feel or loud enough for another person to hear. Some patients are unaware of their joint sounds. Joint sounds can be described as either click or crepitus. A click is a single distinct sound. If loud, it can be described as pop. Crepitus is a grating, gravel-like sound. The majority of joint sounds are associated with articular disc mandibular condyle complex pathology. Joint noise can be detected on both opening and closing. The degree of opening and closing when sound occurs can provide useful clinical information and should be recorded. It can be documented as either early or late opening and or closing click. In a patient with no underlying TMD, mandibular movements should be within normal range of motion without deviations or deflections. There should be no TMJ sounds. First locate the lateral pole of the joints by placing your hands in the preauricular area. Instruct the patient to slowly open and close. You should feel mandibular condyle movement. If unsure of the correct positioning, instruct the patient to clench on their back teeth. There should be no movement of the condyle. If you detect movement, reposition your fingers posteriorly since you are likely feeling the deep masseter contraction. Joint palpation can be performed at the same time. Healthy muscle or joints do not elicit pain or tenderness when palpated or with function. It is important to remember that pain is subjective and therefore a clinician relies on a patient's feedback. Locate the lateral pole of the joint in the same way when evaluating the joint sounds. Palpate in both open and closed position applying light pressure. It is important to ask the patient for feedback and record any reported discomfort. Open. Let me know if this hurts. Any pain? And close. Any pain? A muscles examination is as important as an examination of the TMJ and its movements. There are four main muscles of mastication, masseter, temporalis, medial pterygoid and lateral pterygoid. The masseter is a rectangular muscle that originates from the zygomatic arch and extends downwards to insert into the inferior ramus of the mandible and it works to elevate the mandible. It consists of two portions based on the direction of the fibers, the deep and superficial. The temporalis is a large fan-shaped muscle that originates from the temporal fossa and the lateral surface of the skull that also works to elevate the mandible. Its fibers converge and extend downward to form temporalis tendon that inserts into the coronoid process and anterior ramus of the mandible. It is divided into three portions based on the directions of the fibers. Anterior portion is palpated above the zygomatic arch and anterior to the TMJ. Middle portion is palpated above the zygomatic arch and directly above the TMJ. Posterior portion is palpated above and behind the ear. The medial pterygoid muscle originates from the pterygoid fossa and extends downward, backward, and outward to insert into the medial surface of the mandible ramus and the angle of the mandible. Along with the masseter, it forms a muscular sling that supports the mandible at the angle and elevates the mandible. The lateral pterygoid muscle is divided into superior lateral pterygoid and inferior lateral pterygoid muscles. The inferior lateral pterygoid originates from the outer surface of the lateral pterygoid plate and inserts into the neck of the mandibular condyle. It is active in protrusion and lateral movements. The superior lateral pterygoid originates at the infratemporal surface of the greater sphenoid wing and inserts into the articular capsule, the neck of the condyle, and the articular disc. It functions to stabilize the articular disc with closing. Direct palpation of the lateral and medial pterygoid muscles is not reliable. These muscles can be assessed by evaluating symptoms during functional manipulation. When a patient's history is negative for TMD and there is no pain with palpation of temporalis and masseter, it is unlikely that the other muscles will be symptomatic. Muscle palpation is accomplished bilaterally using polymer surface of the middle finger with index finger and the ring finger resting of the adjacent area. Apply a single firm thrust for one to two seconds. Just like you did palpating the joint, ask the patient for feedback if there's any pain. Remember, pain is subjective. Please let me know if you have any pain. The deep portion is palpated just below the zygomatic arch and in front of the TMJ. If unsure about the proper placement, have patients squeeze their teeth together. You should feel muscle movement underneath your fingers. If no movement, walk your fingers slightly forward. The superficial portion is palpated slightly forward. Position your fingers below the zygomatic arch and move down towards the inferior ramus and angle of the mandible. To palpate the temporalis muscle, I will again operate bilaterally and apply and hold firm pressure. Starting with the anterior belly, I proceed to the middle and posterior bellies, feeling the tightness for knots and asking the patient for feedback. Any pain? The temporalis tendon is palpated intraorally, unilaterally. Place index finger on one hand on the anterior ramus of the mandible intraorally and another hand extraorally and move upwards towards the coronoid process. This will be repeated on the opposite side. Go ahead and open for me. Does this hurt? Mm-mm. OK. Thank you. This evaluation allows the clinician to assess and document pretreatment baseline condition of the temporal mandibular joint and related functional muscles. Findings should be discussed with the patient as a part of informed consent, although positive findings should not always be interpreted as poor candidacy for oral appliance therapy. Individual treatment decisions should be made based on a clinician's level of expertise. I hope you have found this presentation clinically useful. Thank you for joining me.

Tania Kushner

screening evaluation

TMJ

muscular function

dentists