Clinical Steps for Complete Denture Construction 4- Steps of recording jaw relation E- Centric Jaw Relation Registration

3. Dr. Amal Fathy Kaddah
Professor of Prosthodontic,
Faculty of Dentistry
Cairo University

4. When you realize you've made a mistake,
take immediate steps to correct it.

5. RECORDING JAW RELATIONSHIPS
1. Check denture foundation.
2. Establish facial contour.
3. Establish occlusal plane.
4. Maxillary face-bow record.
5. Determination of vertical dimension of
centric occluding relation.
6. Determine centric relation at the accepted
vertical dimension.
7. Locking device ( Recording the C.O.R.)

6. 1. Orientation relations
2. Vertical relation, and
3. Antero - posterior relation
Three - dimensional record
Boucher classified jaw relations into three groups

7. 1- ORIENTATION RELATIONS
• Orientation of maxilla in relation to base
of skull and the hinge axis
The axis can be located by the facebow.
2- Vertical relation
• Orientation of occlusal plane

8. Orientation of occlusal plane
and the Vertical relation
• Help in achieving esthetic, phonetics
and mastication.
• Affect stability of complete denture &
ultimately result in alveolar bone
resorption if not properly achieved.

9. Methods of determination
of centric relation

10. Jaw
Relations
Static
Methods
Wax wafer
method
Graphic
tracing
Dynamic
Methods
Jaw Tracking
Devices
Functional
recording

11. • Occlusal blocks and facial contour
• Occlusal Plane
• Vertical Dimension
• Centric Relation
• Eccentric Relations
Wax registration method
(Wax wafer method)

12. Wax Registration Method
I- Check denture foundation
For Extension, Retention and Stability

13. Check Bite Method
II-Establish facial contour and
orientation of occlusal plane

14. III- Determination of occlusal plane
3- Physics and mechanics (leverage action
and parallelism)
Regarding:
1- Aesthetic appearance
of the teeth
2- Function (chewing and
speech)

15. III- Determination of occlusal plane

16. The interpupillary plane The Ala-tragus line
III- Determination of occlusal plane

17. III- Determination of occlusal plane

18. Check Bite Method
Guide lines
1- Central line
(midline)
2- The corner line
(canine line)
3- The high lip line
and low lip line

19. Check Bite Method
Notch Preparation

20. Occlusion rim notched
to aid stabilizing the
record bases

21. IV- Mounting to the upper
cast
V. Determination of the
Vertical dimension of
occlusion

22. 2 to 4 mm
Vertical Dimension
V D O = V D R - F W S

23. VI. Centric Jaw Relation
Registration

24. Centric Relation Registering
1- Patient in a Slightly Supine
position

25. 2. CRITICAL! Check that record
base heels/rims do not touch
Eliminate contact with record
bases

26. 3- Equalize pressure of occluding
forces
Maintain even contact between the upper
and lower occlusion blocks without
displacement of denture supporting tissues,
at the predetermined
vertical dimension of
centric occluding
relation.

27. 4. Remove 2 mm. of wax from the
lower occlusion block. Replace
them by 4 mm. softened wax.

28. 5. Evenly soften the wax by tapping it
with the edge of a heated wax spatula.

29. 6- Both rims should be inserted into the
mouth and Stabilized using index fingers on
the flange and the thumb under the
symphysis to held it firmly in place

30. 7- Guiding the mandible into centric position
a. Index fingers on the rim, thumbs under
symphysis

31. Centric Relation Registering
b. Jiggle the mandible to freely arc
c. Allow the patient to close into contact
d. Ask the patient to
bite or close on
your fingers
posteriorly to close
the rims together

32. – Do NOT push the mandible or
dislodge the record base
– Medium must be dead soft
– Minimal closing pressure
(Yurkstas and Kapur)
Centric Relation Registering

33. e- Let the patient occlude lightly in
centric and displace 2 mm from the
soft wax
8-The vertical dimension is re-checked.

34. Check Bite Method
9. Mark the Central line and canine
lines extending from upper rim to
lower rim in centric relation position

35. Check Bite Method
10- Remove occlusion blocks together, Rinse.
A sharp imprint of the V-shaped notches should
be recognize.
11. Remove all displaced wax outside the occlusal
surface of the lower block. It may act as
inclined planes, Rinse.
Registration Should be
Sharp, Not Rounded
Keep Wax Neat

36. 12- Return occlusion blocks to the mouth to
check correctness of centric occluding
relation record. The midline of the mouth
should be rechecked and scored with a knife
on the occlusion rim
Recheck the registration repeatedly

37. 13. Assemble the two occlusion blocks together
outside patient’s mouth according to the
locking projections. The trial denture bases
should not be touched posteriorly, Rinse.

38. Locking device
The imprints of V-shaped
notches are used to lock upper
and lower occlusion blocks.

39. Methods to guide the mandible
in centric relation
1- Patient in a Slightly Supine position.
2- Tongue retrusion.
3- Swallowing.
4- Biting operator’s fingers.
5- Relaxation.
6. Fatigue X
7- The temporalis muscle check X

40. Guiding the patient to close in centric relation is done
by saying to the patient, "Close on your back teeth".
If the thumb is not placed against the chin, most
patients will close anteriorly to the centric occlusal
position. However, strong pressure should not be used
on the chin, otherwise the jaw will protrude
1- Chin push guidance (CPG) (Kabnacell 1964)
Thumb at the menton

41. Guiding the patient to close in centric relation is
done by asking the patient to touch a wax knob
placed on the posterior border of the maxillary
base in the midline by the tip of his tongue
(tongue retrusion).
Knob for tongue retrusion
2- Tongue retrusion
Thumb at the menton
Helkimo et al 1973

42. 3- Using index and thumb fingers of the left
hand to stabilize the upper flange and the
index fingers of the right hand to stabilize the
lower flange and the thumb under the
symphysis to held it firmly in place

43. 4- Bimanual guidance or manipulation
Using index fingers on the flange and the
thumbs under the symphysis to held it firmly
in place

44. 5- Ramus assisted chin point guidance
Simon and Nicholls (1980)
Thumb at the chin (posterior pressure) while
index and second finger on the lower border
(upward pressure)

45. Take Care during Making the Record
1. Ensure wax is dead soft
2. Ensure smooth arc of closure, no
horizontal deviations ( e.g. due to pain)
Have patient close into record correctly
3. Use index fingers and thumb to stabilize
the record bases.
4. Do NOT push the mandible or dislodge
the record base

46. 5. Patient opens, relaxes, and slowly
closes (Jiggle the mandible)
• Gently arc the mandible in a hinge-
like motion
• Operator uses tactile senses to
ensure the mandible does not
translate
Take Care during Making the Record

47. 6. Never instruct the patient to
bite firmly nor quickly >>
Causes translation or
inaccuracy in the record.
Take Care during Making the Record

48. 7. Ask patient to stop as soon as you
asked him to stop (the correct position
has been reached)
Some may not be able to tell when wax
records contact.
8. The trial denture bases should not be
touched posteriorly
Take Care during Making the Record

49. laboratory Procedures

50. 1. The articulator still locked in centric, the incisal pin should be
flush with the upper member of articulator and the upper
mounting being properly secured in place.
2. Seal upper and lower occlusion rims in the proper relation before
attaching the lower cast to the mounting ring with plaster.
3. Invert the articulator and place the lower occlusion rim to be
properly related to the upper according to indices taken from the
patient’s mouth.
4. Both occlusion blocks are properly seated on their casts without
interference or hitting of the rears, Apply plaster on the lower
cast and close the upper member upon it.
5. Trim the mounting neatly and wash all plaster off the articulator,
never present a dirty articulator or rough untidy mounting

51. Wax Registration Method