ELECTROGNATHOGRAPHY An In Depth Study

1. ELECTROGNATHOGRAPHYAn In Depth Study COMPUTERIZED JAW TRACKING

2. JT 3D Light weight Balanced Easier to place More accurate

3. JT3-D • Eight sensors • Enhanced Linearity • No Longer Simply Analog • Six to Eight Times More Sensitive • Sampling Rate Approximately 700 per Second

5. 3-D tracking of mandibular movement Monitors speed Monitors direction Monitors quantity of movement Assess jaw movement Assess the swallow Aids in determining mandibular/ condylar posture for treatment Aids in determining proper freeway space and rest position DEFINITION AND GOALS

6. SCREENING EXAM CHRONIC UPPER QUARTER PAIN JOINT “SOUNDS” MANDIBULAR DYSFUNCTION OBJECTIVE ROM RECORDING TREATMENT MONITORING IME PRE AND POST SURGERY POST TREATMENT MONITORING ARTHRITIC MONITORING INDICATIONS

7. EGN Evaluates: • Mandibular velocity and maximum opening • Bradykinesia and Dyskinesia • Mandibular vertical opening in two planes • Mandibular opening pattern in two planes • Deviations and deflections • Lateral Range of motion; protrusion • Mandibular motion in the swallow

8. Electrognathography • Three dimensional tracking of mandibular movement monitoring speed, direction, and quantity of movement • Can be displayed in an XY display or a sweep display • Up to 4 views can appear on the XY display - velocity sagittal frontal horizontal

9. XY Display Range of Motion Velocity Trace (Open wide/close fast Note: These have the same preset that we name differently for clarity: They have different Patient Instructions Four Windows in Each Trace Velocity Sagittal Frontal Horizontal Sweep Display Evaluating mandibular movement in the swallow (Do teeth occlude?) Measuring freeway space Evaluating stability of rest position Evaluating any lateral movement from rest to CO EGN Has 2 Display TypesNote: XY and Sweep Are Separate Presets

10. RANGE OF MOTION Velocity Discussion

11. VELOCITY TRACE Horizontal Discussion

12. EGN SWEEP/ JT TENS PRESET

13. Keys to QualityElectognathography Recordings • Magnet placement • Patient directions • Jaw tracker placement • Watch patient and screen at the same time • Be sure to get full opening and range of motion

15. JT-3 placement • The patient should be neither flexed nor extended • Jaw tracker placement is critical to accurate readings

16. Electrognatholgy Recording • JT-3D Jaw tracker Upper crossbar parallel to External Auditory Meatus Line. Head gear snug but not tight against the patient’s head. The side arms of the headgear should be perpendicular to the floor • Spacing of side bars equidistant

17. Magnet Placement • Align with center of frenum • Be sure it does not interfere with CO • May need to use lingual side • Must be parallel to line drawn to external auditory meatus • Check magnet during procedure • Groove on patient’s left side facing outward • Align with magnet positioner

21. Measure maximum opening Take two traces Velocity: Open Wide Close Fast Range of Motion Note Maximum Opening in ROM Trace (Active opening) Look for crossover pattern in Velocity Trace EGN XY

22. Electrognathography • Range of motion can be objectively recorded. • Inter-incisal opening is measured on the sagittal trace • Velocity is NOT a factor when looking at range of motion recordings • Practice range of motion directions with patient before recording

24. Note: Protrusive movement is helpful in evaluations for patients to receive appliances for obstructive sleep disorders; also for those who are candidates for nocturnal anterior contact appliances.

25. Electrognathography • Deflections can be observed Shift of the midline to one side that becomes greater with opening and does not return to the midline • Deviations can be observed Shift of the midline to one side that returns to midline. Can be due to either intra or extra-capsular dysfunction

26. Smooth curve Bradykinesia Dyskinesia Egg-shaped Flat terminal velocities (ideal 150 mm/second) Normal opening and closing velocity is 300 to 350 mm/second The velocity trace helps determine whether dysfunction is intra or extracapular. Many bradykinesias are due to muscle dysfunction, while dyskinesias tend to be due to intracapsular dysfunction. If both are present: think Intracapsular What to look for in Velocity Trace

27. Electrognathography • Terminal Velocity Speed of mandibular closure at the time the teeth reach centric occlusion • Normal is approximately 75 mm/sec leaving a flat spot at the top of the tracing • Decreased terminal velocity can indicate noxious occlusal stimulus, displaced disk, hyperactive muscle or a distalized condyle with retrodiscal compression on MI • Note: Discuss Patient Instructions

28. Electrognathography • Additional Diagnostic Terminology • Bradykinesia : Slow opening or closing velocity generally due to muscular dysfunction • Dyskinesia: Abrupt change in the opening or closing stroke generally due to disk disorders or articular surface irregularities • Crossover - seen on sagittal view indicating mandibular retrusion usually due to anteriormisguidance and a retruded mandible. A velocity slow down is often noted

29. Normal XY EGN VELOCITY

30. Is this a Velocity or ROM Trace? How do you know? Bradykinesia Dyskinesia Deflection

31. Normal EGNExcellent Velocity with no Deviation or Deflection

32. Normal EGN

33. Abnormal EGNBradykinesia, Dyskinesia, and Deflection

34. Abnormal Velocity TraceCross over and Decreased Terminal Velocity Timing Cross Over Slow Down Associated with Cross Over

35. Note before velocity trace Note opening pattern Treatment was long term mandibular repositioning with supportive therapy Before and After Tx Brenda B Use the Tile Horizontal Option to Display the Following Slide

37. Dyskinesia Sample Young female patient Short Term appliance Therapy Accompanied with Significant Improvement in JVA integral

40. Using Tile Option to Print • Can Have Several Windows Printed Together • Open the Windows • Choose Tile Horizontal Or Vertical Note: Highlighted Window (the one last opened) will appear first.

41. Use the Tile and Options Bar • Choose Amanda L in your TOTAL BioPAK Database • Choose the two velocity traces to compare • Open wide close fast 2/15/2000 • Open wide close fast 6/20/2000 • Create the following printout

43. Evaluate Treatment Outcome • Open Jeff R • Go to Velocity Trace Before and After Treatment to Compare • Use Horizontal Tile to Display Comparative Traces without the Horizontal Window • Be sure that the original trace is on top

44. EGN XY • Note that the maximum opening will usually be greater in the ROM trace (measuring active rather than passive opening). • Abnormal velocity patterns that demonstrate on bradykynesia should be retaken for accuracy and optimum patient function.

45. 40.9 Passive Opening ROM 38.9 Active Opening Velocity Note Maximum Openings Difference

46. Initial Trace Trace Retaken with Proper Instructions

47. Crossover Pattern / Sagittal ViewOf Velocity Trace • Due to retrusion during mandibular closure • Often to avoid anterior tooth contact (anterior misguidance) • May be due to a narrow maxillary arch or retruded mandible • Will often see slow down in velocity at or near the same time as the crossover

48. Cross Over with Bradykinesia

49. XY EGN / FRONTAL VIEW • DEVIATIONS • DEFLECTIONS • LIMITATIONS NOTED IN LATERAL EXCURSIONS TO CONTRALATERAL SIDE OF CLOSED LOCK CASES

50. 4.0 mm Deviation Question: How Large is this Deviation? Lateral: 5 mm per division DEVIATION QUESTION: HOW LARGE IS THIS DEVIATION?