Clinical Removable Prosthodontics Forth Year

1. CLASSIFICATION OF JAW RELATIONS :
1.Orientation relations establish the references in the cranium
2.Vertical relations establish the amount of jaw separation
allowable for use for dentures
3.Horizontal relations establish front- to-back & side-to-side
relations of one jaw to the other

2. Once you have accepted an impression, it
will be packaged and sent to the
Laboratory for fabrication of the:
1- Master Cast
2- Trial Denture Base with an Occlusion Rim

3. If the jaw relations are incorrect,
the dentures will move in order
to occlude with each other and
– will subsequently be dislodged
from the ridges during function.

4. ORIENTATION RELATIONS :
1. Occlusal plane orientation
2. Cranio-maxillary orientation, recorded either by:
A. Following BONWILL triangle, or
B. Using face-bow transfer with adjustable
articulator

5. 1. OCCLUSAL PLANE ORIENTATION
Occlusal plane represents the mean of the curvature of
occlusal surfaces of teeth.

6. The Occlusal Plane

7. Factors affecting the orientation of Occlusal plane :
1. Esthetics
A. Height of occlusal plane, ( interiorly ).
B. Camper’s line , ( posteriorly )
C. Linea alba ( recently edentulous pt )
2. Functions:
Relation of occlusal plane to lower lip & tongue :
A. Phonetics- production of F ,V ,PH sounds
B. Chewing- the plane is below greatest convexity of tongue
3. Parallelism
-parallel to both ridges
4. Anatomical
factors
A. Upper arch, no specific landmarks posteriorly
B. Lower arch, ( Corner of the mouth & Retromolar pad )

8. Anteriorly : Occlusal plane parallel to interpupillary line
Posteriorly : Occlusal plane parallel to ala-tragus line (Camper’s line) runs
from inferior border of ala of nose to superior border of tragus of the ear

9. The Occlusal Plane
Retromolar Pad

10. The Occlusal Plane
Retromolar Pad

11. The Occlusal Plane
Position of Anterior Teeth dictated
by Esthetics and Phonetics

12. The Occlusal Plane
Camper’s Line

13. The Occlusal Plane
Retromolar Pad

14. Linea alba is hyperkeratinized zone occurs at level of occlusal
interdigitation ( a landmark to verify occlusal plane )
Lower occlusal plane when projected
behind must extend to the level between
posterior 1/3 & anterior 2/3 retromolar pad

15. Characteristics of an ideal record base:
- Strength and rigidity
1- Accuracy, The record base should not rock on the cast
2- Smooth, rounded well polished borders
- Thickness of borders and palate must resemble
those of the finished dentures
1- Palate must be 1-2 mm thick
2- Contour of the denture borders are defined by the land
area of the master cast.
3- Record base must not extend onto land area of the cast

16. Completed record base check list:
- Palate should be 1-2 mm thick and well adapted
- Retromolar pad area is covered
- Polished peripheries and palate
- No porosity or voids
- Flanges smooth and rounded
-Tissue surfaces are well adapted
Posterior aspect of upper rim
can contact ascending ramus. If
undetected, it can prevent
accurate CR or sufficient
freeway space to be obtained

17. Level of upper occlusal plane is a matter of judgement ( 2mm
below lower margin of resting upper lip
Occlusal plane guide
( Fox plane )

18. Occlusal plane must be parallel to ala-tragus line . Occlusal
plane guide provides a useful method to asses the position of
occlusal plane in relation to the face

19. Level of occlusal plane
1. It is located at the midpoint of interarch distance
2. Upper occlusal rim must be reduced 2mm below level of
upper lip during speech .
3. Lower occlusal rim must be at level of lower lip & angle of the
mouth. Posteriorly , it must be 2/3 height of retromolar pad.

20. Tentative occlusal plane is adjusted even after mounting on
the articulator . Ideally , if it is parallel to upper & lower
alveolar ridges, the denture will gain optimum stability

21. Too high occlusal rim ,hard to
position food on occlusal surface

22. 1. A little lower occlusal plane with short lips
2. A little higher occlusal plane with long lips & in the elderly

23. Nasolabial angle of 90 is desirable
depending on prominence of columella

24. Upper record block providing inadequate support
to the upper lip –nasolabial angle is obtuse.
Addition of wax to the labial face of the
upper record block providing more support
for the upper lip –nasolabial angle is 90º.

25. II VERTICAL RELATIONS
Vertical dimension
It is the vertical measurement of the face between any 2 points
located , one above and one below the mouth ,in the midline

26. VERTICAL DIMENSION OF OCCLUSION- VDO
It is the vertical dimension of the face when the teeth
or occlusion rims are in contact in centric occlusion
It is the position which must be determined before
teeth arrangement & which must be established on
articulator

27. VERTICAL DIMENSION OF REST- VDR
It is the vertical separation of the jaws or the
vertical dimension of the face when the teeth are
not in contact & the mandible is in physiologic
rest position.
VDR is used clinically as a reference position to
determine VDO of all prosthetic restorations
:

28. Interocclusal distance ( freeway space)
The distance between occluding surfaces of upper & lower
teeth when the mandible is in its physiologic rest position
Significance :
1. Relaxation of masticatory apparatus
2. Minimal activity in elevator & depressing muscles
3. No strain on TMJ capsules
4. Essential for the Health of periodontal tissues when
natural teeth are present

29. Variability of rest position
Due to hypotonicity & hypertonicity of muscles
# Short term variables affected by
1. head posture 2. stress 3. extraction of teeth
# Long-term variables are affected by
1. age & health status
2. bruxism

32. Upper lip area
protrudes
4-6mm
II
Forehead, base of
nose, chin are in line
2-4mm
I
Chin protrudes & upper
lip area retrudes
0-2mm
III

33. • Vertical dimension
at Rest (RVD)
• Vertical dimension
at Occlusion (OVD)
• Free Way Space
(FWS)

34. Interocclusal distance : FREEWAY SPACE
“VDR“-VDO” ”
Distance between occluding surfaces of maxillary and mandibular
teeth when the mandible is in its physiologic rest position
Interocclusal
distance

38. Reduction of freeway space results in :
1. Excessive loading of denture bearing tissues
2 . Elevator muscles are unable to return to their
normal resting length
3 . Continuous muscular activity results in pain
Increasing of freeway space results in :
1. Reduction of masticatory efficiency
2. Poor facial appearance & cheek biting
3. developing symptoms related to TMJ

39. Patient appeared as an Angle’s class III malocclusion & but this
is caused by overclosure of the dentures

40. Overclosure of dentures

41. OVD is too great , face looks
distorted & lips are incompetent
OVD is too small , vermilion
border appears thin & wrinkles
occur around lips & protruded
chin

42. Both patients are wearing CDs
which are in occlusion
facial appearance shows
excessive VDO
a gross loss of VDO freeway
space is approximately 10mm

43. Excessive freeway space
corrected VDO

44. Failure to provide an adequate VDO results in the anterior lower
ridge assuming a more labial relationship to the upper ridge

45. Etiology: riboflavin deficiency, overclosure
from loss of vertical dimension, oral skin
bacteria and fungi (namely Candida)

46. METHODS OF DETERMINING VDR :
1. Esthetics, ( lips, angle of the mouth, labiomental angle )
2. Phonetics
3. Patient’s tactile sense
4. Swallowing and Relaxation
5. Facial measurements
(A) willi’s Measurements
(B) Two dots technique
6. Electromyography

47. VERTICAL DIMENSION
1.Facial Measurements :
-- patient sits comfortably, looking straight ahead
-- insert maxillary record base
-- place point of reference on nose & chin
-- instruct patient to wet lips and swallow
-- mandible comes to rest position
-- measure the distance between reference points
2. Tactile Sense- where patient feels most comfortable
3. Phonetics- Repeat the letter “mm-mm” and relax
4. Facial Expression- recognize patient’s relaxed rest position
5. Anatomic landmarks- average measurements,
*No one method for determining rest position can be
accepted as being valid for all patient’s

48. Correct VD as the lips contact each other
lightly before wax rims contact when the
mouth is closed
VD affects lips appearance: amount of
vermilion border that is visible ,folds of corners
Equal proportions of the forehead & middle of
the face & lower face

49. WAX RIM CONTOUR
Before adjustment
After adjustment
With lips at rest, wax rim must project 1-2 mm below the lip line.

50. Upper record rim trimmed well to provide a good labial support,
that results in a more pleasing appearance

51. Pair of dividers will measure the distance between dots
marked on the nose & chin

53. Methods of determining VDO
1. Pre-extraction records : a) Willi’s gauge
b) Profile tracing
c) Face masks
d) Articulated study casts
e) Profile photograph
f) Radiogragh
2. Measurement of former denture
3. Power point ( BOOS Bimeter )
4. Phonetics “ closest-speaking space “
5. Ridge relationship

54. Willis gauge measures VDO before extraction & records the
distance on the pt.’s chart for future reference

55. Effects of excessively increasing the VD (Over opening )
1. Discomfort
2. Trauma
3. Instability
4. Loss of free way space
5. Clicking teeth
6. Appearance
Effects of excessively reducing the VD ( Over closure )
1. Appearance ( poor esthetics )
2. Inefficiency
3. Cheek biting
4. Angular cheilitis
5. Pain in the TMJ
6. COSTEN’S Syndrome

56. 1.
1-Insufficient
2-Correct
2.
3.
VD ,as pt. closes from rest position ( overclosure )
VD ,lips touch one another easily & naturally
3-Excessive
VD, difficult to bring the lips together ( overopening )

57. HORIZONTAL RELATIONS
CR & CO
Significance of recording CR
Eccentric relations

58. Significance of CR
1.CR is a definite learned position.
2.Pt. can voluntarily & reflexly return to this position.
3.CR can be recorded & repeated.
4.CR is a reference position in recording jaw relations & a starting
point to develop occlusion. It is a point of return.
5.Edentulous pts. use CR in mastication & other mandibular
activities ( such as swallowing).
6.Most of proprioceptors guiding the mandible in CO are lost in
edentulous pt. So, opposing artificial teeth contact in CR due to
loss of these guiding influences.

59. 7.CR can be verified
8.Occlusion is more stable if teeth occlude when the jaws are in
CR.
9.Harmonizing CO to the established CR will arrange the teeth to
meet evenly on both sides of dental arch during function. If we
fail to register this CR, we build into our restorations premature
contacts that will be very traumatic to the supporting structures
10.CR must be recorded correctly to permit accurate adjustments
of condylar guidances for other eccentric movements .
11.CR is the only relation that can be repeatedly duplicated during
treatment.
12.CR is prosthetically convenient.

60. Methods of recording CR :
1- Interocclusal check record method
2- Graphic methods
3- Functional methods ( chew-in method )
The primary requirements for making CR record:
1. Record horizontal relation of mandible to maxilla at proper VDO.
2. Exert equal vertical pressure while making the record.
3. Avoid distortion of record until casts are accurately mounted.
4. CR record can be repeated or verified

61. Interocclusal check record method

62. The commonly used materials for making interocclusal record
are : wax, impression compound, ZOE and impression plaster

65. Graphic methods: Gothic arch tracers :
1. Extra oral tracers.
2. Intra oral tracers.

66. Extra oral Gothic arch tracer

68. Intra oral Gothic arch tracer

69. Obtaining a gothic-arch tracing intraorally

73. Functional methods ( chew-in method )
Require a tentative interocclusal wax record of CR at tentative
VDO. Adjust recoding media at VD in excess to predetermined
VDO. Correct VDO is obtained as pt. closes the jaws
Patterson’s Method:
-Trench or trough is made in lower occlusal wax rim
-Abrasive-plaster mix is loaded into trench
-Occlusal rims inserted & pt. performs mandibular movements
to have compensating curves on abrasive-plaster mix
Plaster-pumice rim with occlusal height greater than recorded height for wax
rim

75. Jaw Relation Stage

78. Tooth Position
Resting
lip line.
Smiling
line.
Speaki
ng line.

80. High lip line:
The greatest height to which the lip is raised in
normal function or during the act of smiling
broadly.
Low lip line:
The lowest position of the inferior border of the
upper lip when it is at rest, OR, the lowest
position of the superior border of the lower lip
during smiling or voluntary retraction.

81. Horizontal relation
• Types: A) Centric relation
• Def, significance, ms involvement,
• Relation C R to: vertical relation, hinge axis, centric
occlusion
• Complication in recording C.R.
• Methods aid pt. to retrude mandible
• Factors affect equalization of pressure
• Methods of recording C R:
• 1.Direct check bite method (wax wafer)
• 2.Function methods: pumice& plaster, three studs, in
wax ,petterson, Ganathodynmeter)
• 3.Physiologic method
• 4. Gothic arch method (intraoral& extraoral
• 5.Recording condylar path( Stereographic& pantographic
tracing
• 6.Cephalometeric & ms conditioning