1. VERTICAL & HORIZONTAL JAW RELATIONS FOR COMPLETE DENTURE

2. Classification Three dimensions:- Orientation relation
Vertical relation
Horizontal relation

3. Vertical Jaw relation
The facial height that exists between two arbitrarily selected points, one in the mandible & the other in the maxilla (Halperin) Or
It is the distance between the two selected points, one on fixed & one on movable member (GPT 1999)

4. Established by two things but under different conditions
- mandibular musculature
- Occlusal stops

5. Vertical jaw relation can be classified as
Vertical relation of rest.
Vertical relation of occlusion.

6. Vertical Relation of Rest
Physiologic Rest Position
It is the vertical and horizontal position the mandible assumes when the mandibular musculature is relaxed and the patient is upright (Davenport) Or
It is the mandibular position assumed when the head is in upright position and the involved muscles particularly the elevator & depressor groups are in equilibrium in tonic contraction & condyles are in a neutral unstrained position (GPT 1999)

7. Vertical Relation of Occlusion
The face height that exists when the teeth are in occlusion (Halperin) Or
It is the relation of the mandible to maxillae when occlusal stops are provided by teeth or occlusal rims (Boucher’s)

8. The difference between the vertical relation of occlusion & the vertical relation of rest is the inter-occlusal space or freeway space.

9. Clinical Significance
Constructing or assessing dentures The clinical procedure is to measure the rest vertical dimension & the occlusal vertical dimension & then calculate the freeway space.

10. Relaxation of masticatory apparatus
When the mandible is in the rest position &
the teeth are out of contact there is no
strain on the temporomandibular joint
If new dentures have no freeway space
If an excessive freeway space

11. Variables of the rest position
Short term variables
Long term variables

12. Short term variables
Variables Rest vertical dimension Patient supine Reduced Head tilted -Back Increased -Forward Increased Insertion of lower denture or record block Increased Stress Reduced Pain Reduced Drugs Variable

13. Long Term Variables
Prosthetic treatment has an important long term influence on the rest position.
It has been shown that an average 7 mm reduction in occlusal vertical dimension.

14. Methods of recording vertical relation

15. Common factors The position of the mandible
Patient should be calm, cool and relaxed when the jaw relations are recorded.
Rest position is a position in space not to be maintained for definite period of time.
Advisable to use several methods and compare the results

16. Classification The methods for determining the vertical
relation can be grouped into two categories:
Mechanical Methods
Physiologic Methods

17. Methods for recording vertical jaw relation
Mechanical methods:
Ridge relation: a) distance of incisive papilla from mandibular incisors b) parallelism of ridges
Measurement of former dentures
Pre-extraction records-
Profile radiographs
Profile photographs
Casts of teeth in occlusion
Facial measurements
2) Physiologic methods
Physiologic rest position
Phonetics & esthetics as guide
Swallowing threshold
Tactile sense

18. Mechanical methods Ridge relation: Incisive papilla – stable landmark
Paralleling of max. & mandibular ridges plus 5 degree opening.
Clinical crowns of anterior & posterior teeth- same length
Disadvantage: absence of lower anterior teeth – cannot be used.

19. Measurement of former dentures:
Dentures –measured---correlated ---patient’s face.
Measurements - b/w borders of maxillary & mandibular denture------Boley gauge.

20. PRE – EXTRACTION RECORDS:
profile radiograph
Disadv: exposure to radiation & time consuming
2)Profile photographs
disadv: angulation of photograph
enlargement
3)casts of teeth articulated in occlusion

21. Willis measurements (1939)
Proportional measurement
Lower border of septum of nose – lower border of chin =
outer canthus of eye – corner of mouth.

22. Physiologic methods Silverman closest speaking space
CENTRIC OCCLUSAL LINE
Measured before loss of the remaining natural teeth
Draw centric occlusal line on lower anterior teeth
at horizontal level of Incisal edge of opposing upper anterior teeth.
Sibiliant sounds – s, z, sh, zh, fish, church, judge
Closest speaking space– measurement for vertical dimension
CLOSEST SPEAKING LINE

23. missipi Physiologic methods Electromyography
Methods for determining physiologic rest position
Swallow & relax
Fatigue
Use of phonetics – M sound
Electromyography
Myomonitor
TENS
missipi
Electromyography
demonstrate their activation potential
visual & audio signs– mandibular position
TENS

24. Methods for determining VDO
Niswonger’s method: (1934)
interocclusal distance : 2-4mm at first premolar region.
Two marks-
Base of nose
Chin
Disadvantages;
Marks on skin – move –difficult – constant measurement.
Lack of permanent reference points.

25. Tactile methods
patient’s tactile sense as a guide
Lytle method
Boos biometer gnathodynamometer
Swallowing threshold

26. Lytle method (1964) Central bearing device attached to record bases
Central bearing screws – palate of max. denture base/occlusal rim
Central bearing plate- mand.
Patient participation – very important.
Disadvantage:
Can’t be used in very sensible patients & impaired neuromuscular patients.
Patients tended to register a reduced vertical dimension.
Relied on pt’ muscular perception.

27. Swallowing threshold
Theory: swallows – teeth come together –
very light contact
A cone of soft wax on lower denture base-
contact upper occlusal rims - Jaw too wide open
Flow of saliva - stimulated

28. Effect of increased vertical dimension
Increased risk of trauma- clenching of teeth.
Discomfort to patient
Teeth are liable to contact – causing clicking during speech
Trauma & pain – basal seat areas of denture
Loss of freeway space- muscular fatigue
Clicking sound
Elongated appearance of face
Bone resorption
Loss of retension & stability of dentures
Generalised hyperemia.

29. Effect of decreased vertical dimension
Reduced masticatory efficiency
Poor esthetics
Cheek biting/ tongue biting/ lip biting
Denture look
Angular chelitis
Pain in TMJ
Coston’s syndrome
prognathism

30. Tests to aid in confirming correct vertical relation
Judgement of facial support
Visual observation of space b/w rims
Observation – sibiliant words.

31. Horizontal jaw relations
Eccentric relation
Centric relation
Protrusive record
Lateral record
Centric relation: -- GPT -8
Centric relation is defined as a maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior superior position against the shapes of articular eminences. This position is independent of tooth contact. This position is discernible when mandible is directed superiorly and anteriorly and restricted to a purely rotatary movement about a transverse horizontal axis.

32. Methods of recording centric relation
Boucher's :
A) static methods-
Interocclusal record
Central bearing device
Tracing devices
B)functional methods—chew –in technique
Needles technique
House technique
Essig technique
Patterson technique

33. Static method Causes minimal displacement of recording bases
Intraoral interocclusal records- without central bearing point –using plaster/wax.

34. Preparing Occlusion Rims
Place 3 widely separated lines between the rims in the centric position
CRITICAL! Check that record base heels/rims do not touch

35. Line up Marks
Eliminate contact with record bases

36. Registering Centric Relation
Max & Mand Occusion Rims
Two sharp “V”-shaped notches in the molar/premolar area of each sided wax
Depth 1-2 mm
1-2 mm

37. Ensure Adequate Notch Depth
Too Shallow
- no undercuts

38. Registering Centric Relation
Rehearse making the record without recording medium
Place occlusion rims intraorally
PVS registration material (Memoreg) over entire occlusal rim

39. Thin Layer of Material
Too Thick
Good

40. Thin Layer Want flat record, no excess on sides of rims
Excess material recording of the sides of the rim can cause deflection when checking record

41. Making the Record Have patient close into record
Ensure smooth arc of closure, no horizontal deviations
Use index fingers to stabilize lower record base

42. Alternate Medium
Alluwax
Must be dead soft

43. Registering Centric Relation
Place Alluwax into a 1-2mm slot in maxillary rim
Fill to slight excess
Ensure wax is dead soft
Hot water bath for softening (use care)

44. Keep Wax Neat

45. Registering Centric Relation
Stabilize mandibular record base using index fingers on the flange (or in a recess in the rim) and the thumbs under the symphysis

46. Registering Centric Relation
Patient opens, relaxes,
and slowly closes

47. Registering Centric Relation
Gently arc the mandible in a hinge-like motion
There should be:
No translation
No splinting

48. Registering Centric Relation
Patient slowly closes
Operator uses tactile senses to ensure the mandible does not translate

49. Registering Centric Relation
Patient closes until rims are almost touching (1 mm separation)
Ask patient to stop as soon as this position has been reached
Some may not be able to tell when they contact

50. Registering Centric Relation
Never instruct the patient to bite firmly
Causes translation or inaccuracy in the record

51. Registering Centric Relation
Hold position until set 1-2 min
Remove both rims together
Separate

52. Registration Should be Sharp, Not Rounded

53. Registering Centric Relation Mounting the Mandibular Cast
Ensure record is repeatable
Increase the height of incisal pin 1 mm, invert articulator
Place wax rims together, lute with sticky wax - 4 spots

54. Patterson method Mixture of ½ plaster + ½ carborundum paste.
mandibular movements-Compensating curves
Disadvantages: time consuming.
Graphic methods:
Intra oral tracing & devices–
Extra oral tracing & devices

55. Intra oral tracing Advantages:
Central bearing pins resists biting pressure
Disadvantages:
Not a visible method
Difficult to find true apex
Tracer- definitely seated in a hole
at point of the apex

56. Extra oral tracing
Always combined with an intraoral bearing point- distribute equal pressure on the bases.
More sharper
Tracing plate- mounted on mandibular rim
Adv:
Larger- apex-easily demarcated
Visible during tracing
Disadvantage:
Lack of equal pressure on the ridges

57. significance of CR
Is the ideal arch to arch relationship and an optimum functional position of jaws for the health, comfort and function of the TMJ and musculature.
Is a hinge position. In CR condyles exhibit only pure rotation without any translation.
Mandibular movements return or terminate in centric
It is thus, a reproducible position and therefore serves as a reliable reference to develop occlusion in complete dentures.
Prosthodontic treatment foe edentulous patients- zarb-bolender 12th edn.

58. significance of CR
It is a position where upper and lower teeth are braced against each other during deglutition.
Serves as a reference position for occlusal reconstruction in dentulous situations.
It is a posterior border position and the posterior limit of the envelope of mandibular motion.
Prosthodontic treatment foe edentulous patients- zarb-bolender 12th edn.

59. Eccentric relation record
Protrusive relation record
Lateral relation record

60. Methods for recording eccentric jaw relation
Functional method- needles- house & patterson technique
Graphic method
Tactile / direct check record methods

61. Protrusive relation Christensen’s phenomenon
Due to downward displacement of the condlyes along the articular slope.
Protrusive records are made of-
Direct protrusive check record
Graphic method
Functional procedures

62. Lateral jaw relations Common methods: Graphic method
With check bites of wax
With positional records of stone/plaster
Pantography
Hanau’s formula:
L = H/ L=lateral condylar inclination
H=Horizontal condylar inclination

63. Bilateral manipulation method
Method for recording centric relation
Procedure:
position the chair-lie back flat
Strech the neck by pointing the chin up
Fore fingers –both hands-lower border of mandible
Little finger-angle of mandible
Thumbs-into notch above symphysis
Condyle is forced upward & backward
Condyle –uppermost position-jaw hinge freely.
Other methods
Celluloid strip method
Softened wax method
Deep heating/ pooling method

64. Consequences of incorrect centric relation recording
Natural dentition– damage to periodontal structure, hypersensitivity, excessive attrition, hypermobility of teeth.
Pain & dysfunction of masticatory muscle, headache, neck& shoulder pain.
Dentures- not in centric relation— premature contact.
TMJ dysfunction— condyle press upon peripheral vascular & innervated part of articular disc.
Mucosal irritation & soreness.
Spasm of muscle of mastication
Resorption of residual alveolar ridges.