step by step description of surveying and designing procedure for cast partial denture from Dept of Prosthodontics, VSPMDCRC, Nagpur

1. 1

2. REMOVABLE PARTIAL DENTURE
2

3. The best way to cure most of the ills of partial denture
prosthesis is to anticipate the troubles which may be
encountered & to change the conditions so that they never
happen.
There is no way more sure of accomplishing this than
by
…..Intelligent use of the
Surveying & Principles of Design.
3

4. Department of Prosthodontics
VSPM Dental College, Nagpur

5. 5

6.  Until 1918s most RPD were designed and
constructed by time honored method of “eye
balling”. A prosthesis made on the basis of
educated guesses.
 The turning point in the partial denture construction
from guess work based on clinical experience to
scientifically based procedure was the appearance
of dental surveyors in 1918
6

7.  Dr.A.J.Fortunati is thought to be first person to employ a
mechanical device to determine the relative parallelism of
tooth surfaces.
 Boston in 1918 has demonstrated a method for charting
correct clasp placement by using a parallelometer.
 First such instrument to be produced commercially was
NEYS instrument.
7

8. Basically two types of surveying methods
 Surveying by using parallelometer-
used commonly
 Optical surveying by using light beams-
rare in practice
8

9. 9

10. NEED FOR SURVEYING FOR RPD…??
10

11. 11

12. CAST SURVEYOR
 The cast surveyor is an instrument by means of which
these principles may be applied
 Dr. A. J. Fortunati is thought to be the person to
employ a mechanical device to determine the relative
parallelism of the tooth surfaces
12

13. DENTAL MODEL SURVEYOR
 The dental model surveyor is essentially a
parallelometer, an instrument used to determine the
relative parallelism of surfaces of teeth or other areas
on a cast of the jaw.
 The Ney instrument was made available in 1923, it
remains most widely used surveyor in dental field.
There are other surveyors in the market today, but in
the long run they accomplish the same purpose.
 Jelenko’s is the second most widely used.
13

14. PARTS OF SURVEYORS
14

15. Parts of Surveyor
a. Platform
b. Vertical arm
c. Horizontal arm
d. Movable vertical part
e. Cast holder
15

16. SURVEYING TOOLS
Analyzing rod
16

17. Carbon marker
17

18. Undercut gauges
18

19. Wax knife
19

20. Chisel
20

21. What are the types of surveyors?
Types of Surveyors
1. Ney Surveyor
2. Jelenko Surveyor
3. Williams Surveyor
4. Retentoscope Surveyor
5. A 2000 – Buchnann Surveyor
6. Micro analyzor
7. Stress – O-Graph
8. Optical surveyor
9. Computerized surveyor
10.Intra Oral Surveyor
21

22. 22

23. Ney Surveyor Jelenko Surveyor
1. Horizontal arm is fixed 1. Horizontal arm is movable
2. Vertical arm is retained by
friction
2. Vertical arm is spring
mounted
3. The shaft remains in any
vertical position until
again it is moved
3.Vertical arm when released
returns to its original
position. It should be held
against spring tension
4. Cast table is moved
around surveyor platform
4.Cast table is fixed with the
magnet in the surveyor
platform
Differences
23

24. THE OBJECTIVE IN SURVEYING
The objective in surveying procedure is to reveal to
the designer those physical characteristics of the
mouth which favor the design of a successful
prosthesis.
24

25. Surveying of the study cast will identify the
structures that will need to be modified in order to
make possible a design of the prosthesis that
a. Can be easily inserted and removed by the patient.
b. contribute optimally to appearance
c. resist unseating forces to a reasonable degree
d. create no undesirable food traps
THE OBJECTIVE IN SURVEYING
25

26. The degree of success achieved will depend upon
the designer’s judicious management and
correlation of four factors.
1. Retentive undercuts
2. Interferences
3. Esthetic consideration
4. Guiding plane surfaces 26

27.  When these four factors have been assessed, the
path of insertion can be decided and design of the
prosthesis established
27

28.  It should be remembered that when a laboratory technician
receives a cast from a dentist on which he is to construct a
removable partial denture , there is nothing the technician
can do but accept that cast as it is.
 He cannot alter the slope of the stone teeth to improve the
position of the height of contour.He cannot cut away the
bony exostosis.
 It is essential that dentist use the surveyor before
planning the treatment for the patient.
28

29. THE SURVEY LINE
OR
THE HEIGHT OF CONTOUR
- It is the greatest circumference of a tooth
in a given horizontal plane.
- The significance of the survey line is that
any rigid, nonflexible part of the prosthesis must
be designed to lie above the survey line and
only flexible part may be designed to go below it.
29

30.  DE VAN 1935 used some clarifying
terms to describe retention.
 He referred to the surface of a tooth
that is occlusal to the height of
contour as SUPRA BULGE and
surface inclining cervically as
INFRA BULGE.
30

31. 31

32. BLATTERFEIN’S CLASSIFICATION
OF SURVEY LINES.
32

33. 1) High survey line 2) Medium survey line
3) Low survey line 4) Diagonal survey line
NZ FZ
NZ FZ
NZ FZ NZ FZ
33

34. Surveying
Diagnostic Cast
Surveying Master
Cast
Auxiliary Uses
USES OF DENTAL SURVEYOR
34

35. SURVEYING THE DIAGNOSTIC & MASTER CAST
1. To determine the most desirable path of placement that
will eliminate or minimize interference to placement and
removal.
2. To identify proximal tooth surfaces that are or need to be
made parallel so that they act as guiding planes during
placement and removal.
3. To determine whether tooth and bony areas of
interference will need to be eliminated surgically or by
selecting a different path of placement.
35

36. 4.To locate and measure areas of the teeth that may
be used for the retention.
5.To determine the most suitable path of placement
that will permit locating retainers and artificial tooth
to the best esthetic advantage.
6.To permit an accurate charting of the mouth
preparations to be made.
36

37. 7.To delineate the height of contour on abutment
teeth.
8.To record cast position in relation to the selected
path of placement for future reference.
37

38. SURVEYING PROCEDURE
Two stages
I. Preliminary analysis of the diagnostic cast
1. determine the most advantageous path of
insertion.
2. to decide upon various types of mouth
preparation that will be required
38

39. II. Definitive design
1. Guidelines are drawn
2. Undercuts are measured and marked
3. Soft tissue undercuts are delineated
4. Design of the framework is outlined
on the cast
39

40. PRELIMINARY ANALYSIS
1. Evaluating the claspability of potential abutment (
Retentive undercut )
40

41. 2. Interferences
Interferences can be dealt with
1.Elimination
2.Alteration
3.Avoidance
4.Exploitation
41

42. A. Soft tissue obstacles
1. Mylohyoid ridge
42

43. 2.Mental ridge of the mandible
43

44. 3. Alveolar ridge with severe labial undercut
44

45. 4. Maxillary tuberosity
45

46. 5.Mandibular torus
46

47. 6. Torus Palatinus
47

48. The surveyor can be used to
determine the best means of
correlating the path of insertion of
the prosthesis with the slope of
the undercut.
48

49. PRELIMINARY ANALYSIS
B. Hard tissue obstacles
Migrated, tipped and rotated teeth may
be found anywhere in either jaw and may
interfere with the ideal design of the prosthesis
49

50. 1.Lingually inclined mandibular teeth
50

51. 2. Maxillary molars and bicuspids,
which tip buccally
51

52. PRELIMINARY ANALYSIS
1.The metal must be concealed
without compromising
support and stability of the
prosthesis
2. Artificial anterior teeth must
be placed in most natural
position.
3. Esthetics
52

53. The surveyor is used to locate existing or
potential surfaces of the teeth that can be
converted to guiding planes by selective
grinding.
Guiding plane does not need to be more than
2 or 3 mm in occluso-gingival height.
4.Guiding planes
53

54. TRIPODING
Methods
a. Tissue surface indexing
b. Art portion indexing
a b
54

55. C. CEMENTED PIN TECHNIQUE
JOHN G. KNAPP ET AL (1979)
The third method of
locating cast is
using thin retentive
pins.
The pins are placed
in the desirable
place to re-orient
the cast in the
surveyor.
55

56. Contouring of wax pattern
Survey ceramic veneer restoration
Handpiece holder attached
to the surveyor ( drill press)
AUXILIARY USES OF SURVEYOR
56

57. Milling of cast crownTapered fissure bur used to cut
Internal rests in wax pattern
AUXILIARY USES OF SURVEYOR
57

58. STEP BY STEP PROCEDURE
58

59.  Examine the occluded diagnostic casts.
59

60.  Indicate the proposed rest
areas by short vertical
lines on the cast below
the tooth with black pencil.
60

61.  Indicate by outlining in red
any cuspal relief that will
be needed to provide
adequate occlusal
clearance for rest spaces. 61

62.  Examine the lingual aspect of the occluded casts for
adequate space for cingulum rests, indirect retainers.
 Use black pencil for marking.
62

63.  Place the cast on the cast holder at horizontal tilt.
Examine the teeth to be clapsed for favorable retentive
undercuts as well as the shape and contour of the
proposed abutment teeth.
63

64. If the shape and contour of these teeth necessitate
recontouring indicate the location and extent of proposed
alteration with red crayon pencil.
Determine the most favorable tilt of the cast that will permit
convent and proper placement of clasps,minor connectors
anterior teeth, and denture base areas.
64

65. CAST TILTING. 65

66.  Tilting is changing the position of the cast,
which thus changes the long axis of each tooth
on the cast relative to the horizontal plane.
66

67. Change in the tilt then changes the
position of survey line and location
and extent of the undercut.
67

68.  Tilting is used to obtain the most favorable path of insertion.
 Tilting is used to increase the desirable undercuts and to
decrease undesirable undercuts.
68

69.  Through tilting, it is
possible to increase the
undercuts on side of the
tooth while decrease them
on other side of the tooth.
69

70. standard reference position 0 degree tilt
TYPES OF TILT
70

71.  Path of insertion is
straight downwards.
71

72.  Path of insertion is
upward and backwards.
72

73.  Path of insertion is
upward and forward.
73

74.  The ultimate goal in the partial denture service is that it has
to go to the place smoothly over the teeth and soft tissue.
 It has to function as it was planned.
 And it has to remain in the place by resisting the dislodging
forces.
74

75. SUMMARY
75

76.  Proper placement and contour of the components of design
can be achieved only through an adequate survey and well
planned mouth preparation.
 The components of RPD must be selected to control stress
to the abutment teeth and tissues caused by forces of
occlusion and movements of distal extension bases.
 Alterations in design may be dictated by the dentists’
prudent judgment.
 Compromising with the ideal principles in the location and
design of components may jeopardize the potential success
of the prosthesis.
76

78. PRINCIPLES
&
DESIGNING
OF
REMOVABLE PARTIAL DENTURE
78

79. ESSENTIALS OF DESIGN
79

80. 80

81. 81

82. PHILOSOPHY OF DESIGN
Physiologic
basing
Broad stress
distribution
Stress
equalization
82

83. Stress director : A device that allows movement
between denture base & direct retainer- (intra-
coronal / extra-coronal) .
Stress Equalization
83

84. 84

85.  a movable joint b/w
direct retainer & denture
base
e.g. hinge, ball & socket
 a flexible connection
b/w direct retainer &
denture base.
e.g. split major
connector, movable joint
85
Types Of Stress Directors

86. - Preserved
alveolar
support of
abutment
- Minimal
requirement of
direct retention
- Massaging
effect on soft
tissues.
- Complicated
design
- Tends to
Fracture
- Difficult to
repair
- Reduced
indirect
retention
- Both vertical &
horizontal
forces-
concentrated-
resorption
Disadvantages
86
Advantages

87. PHYSIOLOGIC BASING
soft tissue is
recorded in its
functioning form
by functional
impression or
relining before
denture delivery
87

88. Disadvantages:
 Compresses soft tissues at rest
 Premature contacts
 Decreased indirect retention- tissue re-bounce at rest.
Denture not well stabilized against lateral forces.
Advantages :
 Intermittent base movement - physiologically
stimulating effect on bone and soft tissue
 reduces frequency of reline or rebase the prosthesis
 Simplicity of design and construction
 Minimal retention is used
88

89. BROAD STRESS DISTRIBUTION
Snowshoe Effect
89

90. Advantages
 Forces distributed over larger area (teeth & mucosa)
 Multiple clasp assemblies: support periodontally weak
tooth.
 easier and less expensive to make.
 Lateral forces may be distributed over as many teeth as
possible
 Rigid components minimize rotational movements
and provide excellent horizontal stabilization .
 These partial denture do not require frequent relining or
rebasing.
90
Disadvantages
 Less comfortable
 Difficult to maintain oral hygiene

91. ESSENTIALS OF PARTIAL DENTURE DESIGN.
 1st step :
‘..to determine how partial denture is
supported.’
91

92. Tooth supported
Periodontal health
Crown- root morphologies
Crown : root
Location of tooth in arch
Relationship of tooth – other
support units
Opposing dentition.
92

93.  Quality of residual ridge –
mucosa
 Extent covered by denture
base
 Type & accuracy –
impression registration
 Accuracy of denture base
 Design – components of
partial denture framework
 Anticipated occlusal load
Tooth & Tissue Supported
93

94. 2nd step :
‘..to connect the tooth & tissue support units.’
- Major & minor connectors
3rd step :
‘..to determine how partial denture will be
retained.’
94

95. 4th step :
‘..to connect retention units to support units.’
5th step :
‘..to outline and join edentulous area to
established design components.’
95

96. 96

97. COLOR CODING
Present system
uses :
acrylic
metal
tripod marks, areas on
teeth that will be prepared
, relieved or contoured
rest seats
survey lines, soft
tissue under cuts
,other information
97

98. Black
Blue Brown
Red
98

99. STEPS IN DESIGNING
1) Examining and occluding diagnostic casts :
99

100. 2) Mark areas of rest seats and to be reshaped
100

101. 3) SURVEYING :
101

102. 4) Rest seats
5) Denture base

103. 7) The major & minor connectors
103

104. 8) Tissue stops
104

105. 9) Retentive elements
10) Reciprocal elements

106. Completed design

107. KENNEDY’S CLASS I PARTIAL DENTURE DESIGN
107

108. 108

109. Distobuccal undercut: T or half T clasp
Mesiobuccal undercut: wrought wire clasp
109

110. RIGID RECIPROCAL UNITS
110

111. IMPORTANCE OF INDIRECT RETAINERS
111

112. KENNEDY’S CLASS II PARTIAL DENTURE DESIGN
112

113. 113

114. KENNEDY’S CLASS III PARTIAL DENTURE DESIGN
114

115. 115

116. KENNEDY’S CLASS IV PARTIAL DENTURE DESIGN
116

117. 117

118. CLASS IV
1.The movement of this type of RPD and resulting
stresses transmitted to the abutment are unlike the
pattern seen in any other type of prosthesis.
2. Esthetic placement of teeth may necessitate their
placement anterior to the crest of residual ridge
resulting in potential tilting leverages. Shorter the
edentulous area , less will be the harmful leverages.
3. Strategic clasp position should be used
118

119. 4. Quadrilateral configuration with anterior clasp
placed anterior and posterior clasp placed as
far posterior as possible, would be the ideal.
5. Major connector should be rigid and broad
coverage should be used in maxillary arch.
6. A functional type of impression - if the
edentulous area is extensive
CLASS IV
119

120.  Aesthetics critical
 Rotational forces can be minimized by retaining
serviceable teeth
 Use of labial flange – retention
 Indirect retention- not required if ideal
quadrilateral configuration is followed.
120

121. Successful
RPD
Sound clinical
judgment
Laboratory
Support
Patient’s
Co-operation
Knowledge of
principles of
design
121

122. 122

123. 123

124. DESIGNING-KENNEDY CLASS III PARTIAL DENTURE
Applegate sub-divided Kennedy class III into 3 groups acc. to clinical
conditions
and type of treatment required :
Group A: saddles are short , abutment are healthy minimum of bone
loss around their roots
Group B: abutments not able to support & provide bracing, saddle is
long
bone resorption around abutment teeth
Group C: saddle exceptionally long , abutment unable to provide any
support 124