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Maxillo-Mandibular Relationships

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Presentation on theme: "Maxillo-Mandibular Relationships"— Presentation transcript:

1 Maxillo-Mandibular Relationships
Occlusal Vertical Dimension And Hinge Axis Relation

2 Occlusal Vertical Dimension
Amount of separation between mandible & maxilla when denture teeth contact

3 Hinge Axis Location Use earbow to record relationship of maxilla to transverse horizontal axis Locate anterior reference point

4 Centric Position Relationship of maxilla & mandible
Anterior/posterior & medio-lateral) Maximum intercuspation of denture teeth

5 Programming the Articulator Protrusive Relationship
Simulate relationship of maxilla to mandible in excursions Denture teeth set in harmonious relationship for function

6 Record Bases (Baseplates) and Occlusion Rims
Used to relate casts on an articulator Record bases simulate the finished denture base

7 Record Bases and Occlusion Rims
Wax occlusion rims simulate the position of the teeth

8 Occlusion Rim Dimensions
Occlusion rims slightly bulkier Provide additional stability during record making

9 Record Base Retention Required for record making & phonetic tests
Inaccurate if loose Use denture adhesive if slightly loose Pronounced looseness - REMAKE

10 Record Base Retention Causes of Poor Retention
Poor adaptation of resin to cast Over- or under-extension Excessive block-out

11 Occlusal Vertical Dimension
Video

12 Arbitrary Adjustment of Occlusion Rims
Adjust separately using average dimensions: Maxillary - 23 mm Mandibular - 18 mm ‘Starting Point’ Fairly rapid adjustment ~ 15 minutes per arch

13 Use a Hot Scapel Blade

14 Use Hot Wax Former or Metal Spatula

15 Maxillary Occlusion Rim Adjustment
Maxillary rim slightly facial to compensate for ridge resorption

16 Maxillary Occlusion Rim Adjustment
Anterior height 1-2 mm below the lip at rest/when the patient slightly smiles

17 Wax rim/tooth display can be adjusted with sex, age, and lip length (Vig: JPD 1978).
Incisal Display 10-20mm 3-4mm 20-25mm 2mm 26-30mm 1mm >30mm Sex & Age Female Male Young Middle Old

18 Position of Maxillary Incisal Edge
Edge of rim touches wet line of lower lip when ‘F’ or ‘V’ sounds Count ‘50-60’

19 Lip Support Lips should be unstrained Naso-labial angle ≈ 90°
Philtrum depressed Vermilion border showing

20 Occlusion Rim Angulation
Occlusal plane parallel to the ala-tragus line

21 Occlusion Rim Occlusal Plane
Mediolaterally, parallels the pupils Fox plane can be used

22 Fox Plane Helps orient occlusal plane

23 Centered Occlusion Rim
Centered over ridge to maximize stability

24 Posterior Occlusion Rim Height
Posteriorly, the occlusion rim intersects 1/2 - 2/3 up the retromolar pad

25 Mandibular Rim Height Anterior height even with the corners of mouth when lip is relaxed

26 Facial Occlusion Rim Relations
1-2 mm horizontal overlap in anterior & posterior in centric position

27 Proper Lip Support Unstrained lips Vermilion border showing

28 Occlusal Vertical Dimension (OVD)
Distance between maxilla & mandible when teeth or wax rims contact in centric position

29 Physiologic Rest Position (PRP)
At rest, lips barely touching Occlusion rims should not touch Intraorally no contact

30 Interocclusal Distance (ID)
Space between wax rims at physiologic rest position Usually 2-4 mm

31 Establishing Occlusal Vertical Dimension
PRP = ID + OVD

32 Establishing Occlusal Vertical Dimension
1. Measure difference between PRP & OVD 2. Feel to ensure movement of mandible 3. Phonetics tests ‘Closest Speaking Space’ Patient sitting bolt upright

33 Establishing Occlusal Vertical Dimension
Check with three techniques to ensure acceptable OVD No one technique 100% correct

34 Patient Sits Bolt Upright Soft tissue position affected by posture

35 Measurements OVD & PRP Use external points for ease of measurement
Small dots under columnella & mid-symphisis Use Boley Gauge, not ruler

36 Measuring Occlusal Vertical Dimension
Measure the distance between dots At PRP At OVD Difference is ID Measurements change each day (position of dots)

37 Measuring Physiologic Rest Postion
Open and close until lips barely touch - Physiologic Rest Position (PRP) Measure distance between dots

38 Measuring Occlusal Vertical Dimension
Open and close until rims touch Measure distance between dots (OVD) Measurement will be different each appointment

39 Establishing OVD Feel for Interocclusal Distance
Close until lips barely touch - PRP Place finger on chin Look away Patient closes until rims touch (OVD) Feel for movement of the mandible

40 Establishing OVD Phonetics Test
Closest Speaking Space Confirms OVD Sibilant sounds ("s", "z", sh", ch") Rims should be at least 1 mm apart Don’t worry about sounds yet

41 Excessive OVD Wax Rims Too High
Insufficient interocclusal distance Remove wax from one or both of the rims Use large wax formers #5 & #7 wax spatulas Red-handled knife Bunsen burner and torch

42 Wax Rim Adjustment at OVD
Flat even contact along entire occlusal surface EXTREMELY CRITICAL If uneven contact, patient may be forced into eccentric position

43 Adjusting Wax Rim Height
Scribe lines parallel to opposing occlusal rim Use as a guides during reduction

44 Eliminating Record Base or Wax Rim Interferences
Patient in Centric Position Scribe three widely separated lines between maxillary & mandibular rims

45 Establishing OVD Remove, superimpose lines
Eliminate contacts between record bases, record base/occlusion rims/casts Only contact should be rim to rim

46 Adjusting Occlusion Rims
Continue to adjust the rims until: interocclusal distance is 2-4 mm even contact along rims in centric position.

47 Excessive Occlusal Vertical Dimension
Sore muscles Soft tissue sore spots Rapid bone resorption Dentures click during speech

48 Inadequate Occlusal Vertical Dimension
Collapsed Appearance - chin too close to the nose or protruding jaw Fatigue when chewing Sore muscles or joints

49 Hinge Axis Location Face-bow or ear-bow used
Record relationship of maxilla to transverse horizontal hinge axis of mandible

50 Hinge Axis Transferred to the articulator
Important to prevent occlusal errors, particularly when cusped teeth are used in dentures.

51 Facebow (Earbow) Transfer Mount Maxillary Cast
2 Video Clips

52 Attach cast with mounting plaster in two steps


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