Orthodontic Therapy and Temporomandibular Disorders .pptx

The goal of the orthodontist is to develop an esthetic smile and a functional masticatory system.

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2. Mithila Minority Dental College and Hospital, LAHERIASARAI, Darbhanga DEPARTMENT OF ORTHODONTICS & DENTOFACIAL ORTHOPEDICS Orthodontic Therapy and Temporomandibular DisorderS 2 Presented by : DR. RAVI RANJAN PGT 1 st YEAR Guided by : DR. ABHISHEK SINGHA ROY (PROFESSOR & HOD)

3. Introduction temporomandibular joint Concept of Orthopedic Stability Finding the Musculoskeletal Stable Position Evaluating the Patient for Temporomandibular Disorders Developing the Orthodontic/ Temporomandibular Disorders Treatment Plan Managing Temporomandibular Disorders Symptoms That Arise During Orthodontic Therapy Summary REFERENCES CONTENTS 3

4. INTRODUCTION There are two main goals of orthodontic therapy: 1. Improving aesthetics Although aesthetics may be the primary goal of the patient (and parent), it is certainly not the most important goal. 2. Achieving sound masticatory function It is actually the most important treatment goal of orthodontic therapy. 4 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

5. The orthodontist is in a unique position to either improve or worsen the occlusal condition while carrying out the aesthetic goals of the therapy. Therefore, the orthodontists to be knowledgeable of normal masticatory function and the goals that need to be achieved to maintain normal function. These goals should be met in all patients, both those with and without masticatory dysfunction. 5

6. This seminar will discuss the principles of normal orthopedic stability in the masticatory system and define treatment goals that will help assure normal masticatory function, and the concepts of how orthopedic instability may relate to temporomandibular disorders (TMDs) will be reviewed, and also when orthodontic therapy may influence TMD symptoms. 6

7. TEMPOROMANDIBULAR JOINT (TMJ) The temporo-mandibular joint (TMJ) is a type of synovial joint that connects the jawbone with the skull. Present in between the glenoid fossa (mandibular fossa) of the temporal bone above and the mandibular condyle. It’s articular surfaces that are lined by fibrocartilage, rather than hyaline cartilage. Fibrocartilage is less susceptible to degeneration and has a greater repair capacity. Textbook Of Craniofacial Growth - Sridhar Premkumar

8. DEVELOPMENT OF TMJ The TMJ structures developed progressively from a block of embryonic mesenchymal cells that imposed between temporal bone and mandible. The TMJ mainly develops in between 7 th and 20 th weeks of intrauterine life . The joint can perform only simple rotation or buccal movements which appears in 8 th week of development. Textbook Of Craniofacial Growth - Sridhar Premkumar

9. FUNCTIONAL ANATOMY It’s a ginglymoarthrodial joint , a joint that is capable of hinge-type movements and gliding movements, with the body components enclosed and connected by a fibrous capsule. The articulation is formed by the mandibular condyle occupying a hollow in the temporal bone(mandibular or glenoid fossa). Textbook Of Craniofacial Growth - Sridhar Premkumar

10. Parts of Temporomandibular Joint

11. MOVEMENTS AND MUSCLES OF TMJ Movements Elevation( closing of mouth) Depression (opening of mouth) Protraction (protrusion) Name of the muscle MEDIAL PTERYGOID MESSATOR TEMPORALIS LATERAL PTERYGOID ANTERIOR BELLY OF DIGASTRIC GENIOHYOID MYLOHYOID Medial pterygoid of both sides Lateral pterygoid of both sides Human Anatomy ( Vol. 3 rd ) – B D Chaurasia - 7 th Edition

12. Movements Retraction (backward movements) Lateral / side by side movements Name of the muscle Temporalis Lateral and medial pterygoids of each side as acting alternatively. Human Anatomy ( Vol. 3 rd ) – B D Chaurasia - 7 th Edition

13. CONCEPT OF ORTHOPEDIC STABILITY In establishing the criteria for the optimum, orthopedically stable joint position, the anatomic structures of the temporomandibular joint (TMJ) must be closely examined. The TMJ is made up of the condyle resting within the articular fossa with the articular disc interposed. The articular disc is composed of dense, fibrous connective tissue devoid of nerves and blood vessels. The purpose of the disc is to separate, protect, and stabilize the condyle in the mandibular fossa during functional movements. 14 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

14. However, the articular disc does not determine positional stability of the joint. The positional stability is determined by the muscles that pull across the joint and prevent separation of the articular surfaces. The directional forces of these muscles determine the optimum, orthopedically stable joint position. This is an orthopedic principle that is common to all mobile joints. The musculoskeletally stable (MS) position is the most orthopedically stable position for the joint and can be identified by observing the directional forces applied by the stabilizing muscles. 15

15. The temporalis muscles have some fibers that are oriented horizontally; however, because these fibers must transverse around the root of the zygomatic arch, the majority of fibers elevate the condyles in a straight superior direction. 16 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

16. The masseter and medial pterygoid muscles provide forces in a supero -anterior direction, which seats the condyles superiorly and anteriorly against the posterior slopes of the articular eminences. 17 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

17. The lateral pterygoid muscles contribute to joint stability by stabilizing the condyles against the posterior slopes of the articular eminences. 18 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

18. The major muscles that stabilize the TMJs are the elevators . The direction of the force placed on the condyles by the temporalis muscles is predominantly in a superior. The three muscle groups (temporalis, masseter & medial pterygoid) are primarily responsible for joint position and stability. However, the lateral pterygoid muscles contribute to joint stability by stabilizing the condyles against the posterior slopes of the articular eminences. 19

19. The complete definition of the most orthopedically stable joint position is that position when the condyles are in their most superoanterior position in the articular fossae, resting against the posterior slopes of the articular eminences, with the articular discs properly interposed. This position is the most Musculoskeletally Stable (MS) position of the mandible . The occlusal contact pattern of the teeth also influences stability of the masticatory system. It is important that when the condyles are in their most stable position in the fossae and the mouth is closed, the teeth occlude in their most stable relationship. The most stable occlusal position is the maximal intercuspation of the teeth. This type of occlusal relationship furnishes maximum stability for the mandible while minimizing the amount of force placed on each tooth during function. 20 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

20. The criteria for optimum orthopedic stability in the masticatory system would be the simultaneous contact of all possible teeth when the mandibular condyles are in their most superoanterior position, resting against the posterior slopes of the articular eminences, with the discs properly interposed. The occlusal condition is the fact that the mandible has the ability to move eccentrically, resulting in tooth contacts. These lateral excursions allow horizontal forces to be applied to the teeth, but these horizontal forces are not generally well accepted by the dental supportive structures; yet the complexity of the joints requires that some teeth bear the burden of these less-tolerated forces. 21

21. When all the teeth are examined, it becomes apparent that the anterior teeth are better to accept these horizontal forces than posterior teeth. Of all the anterior teeth, the canines are the best suited to accept the horizontal forces that occur during eccentric movements. Due to the following reasons: They have the longest and largest roots and therefore the best crown:root ratio . They are surrounded by dense, compact bone , which tolerates the forces better than the medullary bone found around posterior teeth. 22 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

22. There are the following conditions that provide optimum orthopedic stability in the masticatory system. This represents the orthodontic treatment goals for all patients. When the mouth closes, the condyles should be in their most superoanterior position, resting on the posterior slopes of the articular eminences with the discs properly interposed. When the mandible moves into laterotrusive positions, there should be adequate tooth-guided contacts on the laterotrusive (working) side to immediately disocclude the mediotrusive (nonworking) side. The canines (canine guidance) provide the most desirable guidance. When the mandible moves into a protrusive position, there should be adequate tooth-guided contacts on the anterior teeth to immediately disocclude all posterior teeth. When the patient sits upright and is asked to bring the posterior teeth into contact, the posterior tooth contacts should be heavier than anterior tooth contacts. 23

23. Finding the Musculoskeletal Stable Position An easy and effective method of locating the musculoskeletal stable (MS) position is the Bilateral Manual-Manipulation Technique . This technique begins with the patient lying back and the chin pointed upward. Lifting the chin upward places the head in an easier position to locate the condyles near the musculoskeletal stable (MS) position. 24 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

24. The dentist sits behind the patient and places the four fingers of each hand on the lower border of the mandible at the angle. The small finger should be behind the angle with the remaining fingers on the inferior border of the mandible. It is important that the fingers be located on the bone and not in the soft tissues of the neck. 25 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

25. Next, both thumbs are placed over the symphysis of the chin so they touch each other between the patient’s lower lip and chin. When the hands are in this position, the mandible is guided by upward force placed on its lower border and angle with the fingers while at the same time the thumbs press downward and backward on the chin. 26 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

26. Downward force is applied to the chin (blue arrow), while superior force is applied to the angle of the mandible (blue arrow). The overall affect is to set the condyle superoanterior in the fossae (white arrow). 27 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

27. Another method of finding the musculoskeletal stable (MS) position is by using the muscles themselves to seat the condyles. This can be accomplished with a leaf gauge . The concept behind a leaf gauge is that when only the anterior teeth occlude (disengaging the posterior teeth), the directional force provided by the elevator muscles (temporalis, masseter, medial pterygoid) seats the condyles in a superoanterior position within the fossae. The anterior stop provided by the leaf gauge acts as a fulcrum, allowing the condyles to be pivoted to the musculoskeletal stable (MS) position in the fossae. 28 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

28. For effective use of the leaf gauge, the patient must attempt to close down on the posterior teeth with mild force. Enough leaves are placed between the anterior teeth to separate the posterior teeth slightly. The patient is instructed to close by trying to use only the temporalis muscles, avoiding any heavy masseter contraction. Once this has been achieved, the leaves are removed one by one until the teeth become closer, and therefore so that the occlusal relationship can be evaluated in the musculoskeletal stable (MS) position. 29 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

29. EVALUATING THE PATIENT FOR TEMPOROMANDIBULAR DISORDERS Temporomandibular disorder ( TMD) symptoms are common, it is recommended that every orthodontic patient be screened for these problems, regardless of the apparent need or lack of need for treatment. Orthodontic therapy will likely influence the patient’s occlusal condition, it is important to identify any dysfunction in the masticatory system before therapy is ever begun. There are following ways to evaluate the patient for TMDs: A TMD Screen History A TMD Screen Examination 30 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

30. TMD Screen History The purpose of the screening history and examination is to identify any TMD signs and symptoms of which the patient may or may not be aware. The screening history consists of several questions that will help alert the orthodontist to any TMD symptoms. The new diagnostic criteria for TMDs assessment protocol recommends the following questions to identify functional disturbances: Q1 . In the last 30 days, how long did any pain last in your jaw or temple area on either side? No pain Pain comes and goes Pain is always present 31

31. Q2. In the last 30 days , have you had pain or stiffness in your jaw on awakening? No Yes Q3. In the last 30 days , did the following activities change any pain (that is, make it better or make it worse) in your jaw or temple area or either side? Chewing hard or tough food No Yes Opening your mouth or moving your jaw forward or to the side No yes 32

32. Jaw habits such as holding teeth together, clenching, grinding, or chewing gum No Yes Other jaw activities such as talking, kissing, or yawning No Yes 33

33. TMD Screen Examination This should be relatively brief and is an attempt to identify any variation from normal anatomy and function. It begins with an inspection of the facial symmetry. The screening examination should include the following: Muscle Palpation TMJ Palpation Range Of Mandibular Movement Occlusal Evaluation 34

34. Muscle palpation The temporalis and masseter muscles are palpated bilaterally for pain or tenderness during the screening examination. Palpation of the muscle is accomplished mainly by the palmar surface of the middle finger, with the index finger and forefinger testing the adjacent areas. Soft but firm pressure is applied to the designated muscles, the fingers compressing the adjacent tissues in a small circular motion. A single firm thrust of 1kg for 2 seconds duration is usually better than several light thrusts. 35

35. 36 FIG . A, Palpation of the anterior portion of the temporalis muscle. B, Palpation of the posterior portion of the temporalis muscle. Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

36. 37 FIG . A, Palpation of the masseter muscle at the superior attachment to the zygomatic arch. B, Palpation of the masseter muscle at its attachment of the lower border of the mandible. Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

37. Temporomandibular Joint ( tmj ) Palpation The TMJs are examined for any signs or symptoms associated with pain and dysfunction. Pain or tenderness of the TMJs is determined by digital palpation of the joints when the mandible is both stationary and during dynamic movement . The fingertips are placed over the lateral aspects of both joint areas simultaneously. 38 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

38. The fingertips should feel the lateral poles of the condyles passing downward and forward across the articular eminences. Once the position of the fingers over the joints has been verified, the patient relaxes and medial force (0.5kg) is applied to the joint areas. 39 FIG . Palpation of the temporomandibular joint in the closed-mouth position. Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

39. Once the symptoms are recorded in a static position, the patient opens and closes, and any symptoms associated with this movement are recorded. 40 FIG . Palpation of the temporomandibular joint in the opened-mouth position. Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

40. As the patient opens maximally, the fingers should be rotated slightly posteriorly to apply force to the posterior aspect of the condyle. 41 FIG. Palpation of temporomandibular joint with the mouth fully open. Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

41. Joint sounds are recorded as either clicks or crepitation . A click is a single sound of short duration. If it is relatively loud, it is sometimes referred to as a pop. Crepitation is a multiple, gravel-like sound described as “grating” and “complicated.” Crepitation is most commonly associated with osteoarthritic changes of the articular surfaces of the joint. 42

42. Joint sounds can be perceived by placing the fingertips over the lateral surfaces of the joint and having the patient open and close the mouth. A more careful examination can be performed by placing a stethoscope over the joint area. It has been demonstrated that this technique can actually produce joint sounds that are not present during normal function of the joint. 43

43. A screening examination should also include evaluation of the patient’s range of mandibular movement. The normal range of mouth opening when measured interincisally is between 53 - 58 mm . The patient is asked to open mouth slowly until pain is first felt. At that point, the distance between the incisal edges of the maxillary and mandibular anterior teeth is measured. This is the maximum comfortable mouth opening. 44 Range of Mandibular Movement Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

44. The patient is then ask to open mouth as wide as possible, even if this is painful. This measurement is called the maximum mouth opening. A restricted mouth opening is considered to be any distance less than 40 mm. Only 1.2% of young adults, mouth opening less than 40 mm. 45 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

45. The patient is next instructed to move his mandible laterally. A lateral movement less than 8mm is recorded as a restricted movement . 46 FIG. Measuring the distance of lateral eccentric movement using a millimeter ruler. Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

46. Occlusal Evaluation The occlusal examination begins with an observation of the occlusal contacts when the condyles are in their optimum orthopedic position (MS position). This position is located by using a bilateral manual manipulation technique . In this position, the mandible can be purely rotated, opened and closed approximately 20 mm interincisally , while the condyles remain in their MS position. Once the MS position is located, the mandible is brought into tooth contact and the occlusal relationship of the teeth in this joint position is evaluated. 47 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

47. Once tooth contact is achieved, the patient is asked to hold the mandible on the first occlusal contact and the relationship of the maxillary and mandibular teeth is noted. Then the patient is requested to apply force to the teeth, and any shifting of the mandible is observed. If the occlusion is not stable in the MS position, a shifting will occur that carries the condyles away from their orthopedically stable positions to the more stable maximum intercuspal position. This shifting represents a lack of orthopedic stability. 48

48. DEVELOPING THE ORTHODONTIC/TMD TREATMENT PLAN All potential orthodontic patients should be evaluated for both their aesthetic needs as well as for their functional needs. Once the history and examination data are collected, this information is used to develop a treatment plan that will appropriately meet the overall needs of the patient. When a patient presents with only TMD symptoms, the orthodontic therapy is only indicated for TMD patients when it has been determined that orthopedic instability is present and this instability is contributing to the TMDs. 49 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

49. Therefore, when TMD symptoms are present, we should first attempt to determine the orthopedic instability is contributing to the TMD. The best way to identify this relationship is by first providing orthopedic stability reversibly with an occlusal appliance. It is important to remember that orthodontic therapy can only affect TMD symptoms by changing the occlusal contact pattern of the teeth and the resulting function of the masticatory system (improved orthopedic stability). If an occlusal appliance successfully reduces the TMD symptoms, often we assumes that the occlusion and its relationship to orthopedic instability are etiologic factors in the TMD. 50

50. There are several factors that may explain how occlusal appliances reduce symptoms associated with TM disorders: Alteration of the occlusal condition Alteration of the condylar position Increase in the vertical dimension Cognitive awareness Placebo effect Increased peripheral input to the CNS Regression to the mean 51 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

51. When a patient’s symptoms are reduced by occlusal appliance therapy, each of these seven factors must be considered as responsible for the success. All the permanent treatment should be delayed until significant evidence exists to determine which factor was important in reducing the symptoms. This can be accomplished by first allowing the patient to wear the appliance for 1 to 2 months to assure that the symptoms have been adequately controlled. The amount of time needed is dependent upon the type of TMD that is being treated. 52

52. If reducing the use of the occlusal appliance re-establishes the original symptoms, then factors such as the occlusal condition, condylar position, or vertical dimension may need to be considered as potential etiologic factors. The clinical evidence now suggests that a change in the occlusal condition would likely reduce the TMD symptoms, we should accurately mount the patient’s study casts on an articulator and determine the most appropriate method of achieving the goals of orthopedic stability (i.e., Orthodontic therapy). When patients have both needs, we first efforts should be directed toward resolving the TMD symptoms. We may decide to use an occlusal appliance to help reduce the symptoms. 53

53. When an appliance is used, it will not only help reduce symptoms but also assist in locating the MS position of the joint. Once the symptoms are reduced, the orthodontic treatment plan is developed with respect to the MS position of the joints, and therapy can begin. 54

54. MANAGING TMD SYMPTOMS THAT ARISE DURING ORTHODONTIC THERAPY A patient will present with TMD symptoms while actively undergoing orthodontic therapy. These symptoms may demand immediate attention, the traditional TMD therapy would be difficult and likely delay the orthodontic treatment plan. Therefore, the orthodontist needs to have some treatment strategies that will help reduce the patient’s symptoms while orthodontic therapy continues. The first important consideration with a patient who develops new TMD symptoms is to review the orthodontic progress toward achieving orthopedic stability in the masticatory system. 55 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

55. If the TMD symptoms are related to intracapsular concerns such as joint clicking. The orthodontist should locate the MS position of the condyles using a bilateral manual manipulation technique and determine the orthodontic therapy is moving toward developing a favorable inter- cuspal position in the stable joint position. One of the most important, the orthodontist can do for the patient is to provide education . The patient needs to know abouts TMD symptoms. The concept of “ lips together and teeth apart ” is powerful in reducing most acute TMD pains. 56

56. If the acute TMD symptoms are associated with pain, suggests a mild analgesic be used for 5 to 7 days to reduce the pain. An NSAID such as ibuprofen very useful. The patient should be instructed to take 400 to 600mg of ibuprofen three times a day with meals for 5 to 6 days. A conservative therapy for muscle pain is moist heat . A moist, hot towel can be placed over the painful muscles for 15 to 20 minutes and repeated several times a day as needed. This therapy can be very helpful in reducing acute muscle pain. If the patient reports poor sleep quality and is waking up with increased pain, may be suspicious of sleep-related bruxism. When this occurs, a mild muscle relaxant such as cyclobenzaprine , 5 to 10mg before sleep for 5 to 7 days, may be helpful. 57

57. For many acute TMD symptoms, these simple therapeutic interventions will be adequate to resolve the condition. There is no need to alter the orthodontic treatment. The patient should be reassessed in 7 to 10 days to make sure that the symptoms have been resolved. Once the symptoms have resolved, continue with the orthodontic therapy with the goals of establishing orthopedic stability and an acceptable esthetic. 58 Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition

58. SUMMARY The goal of the orthodontist is to develop an esthetic smile and a functional masticatory system. Although initially esthetics is often considered the most important goal, function eventually becomes far more important in the overall success of treatment. Therefore, the orthodontist must always consider how the orthodontic therapy will affect function. 59

59. To maximize sound orthopedic function, the occlusal condition must be finalized in harmony with the MS position of the TMJs. Accomplishing this goal will maximize the success of masticatory function in future years. 60

60. references Orthodontics Current Principles And Techniques- Graber, Vig , Haung , Fleming - 7 th Edition Management Of Temporomandibular Disorders And Occlusion – Jeffrey P. Okeson -8 th Edition Human Anatomy ( Vol. 3 rd ) – B D Chaurasia - 7 th Edition Textbook Of Craniofacial Growth - Sridhar Premkumar Rendell JK, N orton LA, Gay T. Orthodontic treatment and temporomandibular joint disorders. Am J O rthod Dentofacial O rthop . 1992 Jan;101(1):84-7. McNamara JA Jr. Orthodontic treatment and temporomandibular disorders. Oral S urg Oral M ed O ral P athol Oral R adiol E ndod . 1997 Jan;83(1):107-17. 61

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