This document discusses the history and evolution of dental surveyors from their introduction in 1918 to modern computer-aided designs. It outlines key developments in surveyor models over time from early prototypes to current instruments. The purposes of surveyors are to determine the optimal path of insertion for removable partial dentures, identify areas requiring modification, and delineate retentive undercuts and interferences.

1. 1

2. • Introduction
• Historical Perspective
• Definitions
• Objectives of Surveying
• Parts of a Surveyor
• Surveying Tools
• Survey Lines
• Purposes of Surveyors
• Summary & Conclusion
• References
2

3. • Success in the practice of Removable
Partial Dentures(RPD) – knowledgeable &
guided planning of each structural detail of
the prosthesis.
• Until the early 1900s most RPDs were
designed by “eye balling”-a prosthesis
made on the basis of educated guesses.
• The turning point-introduction of dental
surveyors in 1918. 3

4. • 1860 – Dr.J.Richardson
• 1890 – Dr.W.M. Randall’s Technique
• 1905 – Dr.Herman E.S. Chayes’
Parallelometer
• 1918 - Dr.A.J.Fortunati - Bridge
Parallelometer
• 1920 - Robinson surveyor by Philadelphia
Dental Clinic Club
• 1923 – The Original Ney Surveyor
by Weinstein & Roth 4

5. • 1937 – Ney Surveyor-the Current Model
• 1929 – The Original Wills Surveyor by
Noble G Wills
• 1937 – Wills Surveyor-the Current Model
• 1942 – Kings’ College Surveyor
• 1944 – The Roach Surveyor
5

6. >The Electrome >The Retentoscope
>The Stressograph
>Broken-arm > Pendulum Surveyor
>Optical
Surveyor
6

7. • Dr. A.J. Fortunati - the first person to
employ a mechanical device to determine
relative parallelism of tooth surfaces.
• In 1918, he demonstrated the advantages of
using a mechanical device to “map’’ the
of abutment teeth.
• The he used was
originally designed for precision attachment
work
7

8. • The has
been recognized as the first
instrument designed and built
specifically for dental cast
surveying.
• No patent was issued for this
surveyor.
• No references have been found
in the dental literature
8

9.  The first such device to be
produced commercially
 The J.M. Ney Company
introduced this benchmark of
surveyor design to the dental
community in 1923
• U.S. Patent was granted to Dr.
Lewis J. Weinstein of New York
City for this instrument in 1923
9

10. 10

11. MICROSURVEYOR
• Hand held surveyor
• Establishes path of insertion by tilting
vertical arm hinged at the base/platform
• Collapsible into individual parts for easy
storage
11

12. The Wills surveyor
by Jelenko is second
most widely used.
12

13. 13

14. WILLIAMS SURVEYOR
In this table is
adjustable to any
desired tilt and that
degree of inclination
can be recorded for
positioning the cast
at any time.
The distinct
advantage of this
table over universal 14

15. It is equipped with
gauge to provide exact
exact determination of
the undercut being
and so that it makes it
possible to produce
balanced retention
The cast attached
on the table can be
raised and lowered 15

16. 17

17. It consists of two
vertical holders.
One for measuring
undercut and one for
measuring the survey
line.
This is a more
instrument than 20

18. Galloni Isoparallelometer model 1020
More
complicated
cast surveyors
have
attachments
that hold milling
and drilling 21

19. Micro Analyzer
• More
sophisticate
d instrument
• Measure
undercut
electronicall
y in
millimeters 22

20. OPTICAL SURVEYOR
Cast can be surveyed by parallel
instead of the vertical rod.
Parallel light beams are produced by
light bulbs with small dense filaments
and condenser lenses contained in a
The beams are made parallel with
vertical rod of the conventional
by fixing the box to an iron bar. 23

21. The cast is placed on the table and surveyed in a
dark room using parallel light beam.
The survey line is the border of the bright and
dark zones – the line where the light beams are
tangent to the cast creates a shadow
By tilting the table to establish various paths of
insertion undercuts and survey, lines may be
inspected without drawing on the cast.
After securing the most favorable path of
insertion, the table of the surveyor is locked and
survey lines are marked with lead marker. 24

22. INTRA ORAL SURVEYOR
“Intra oral surveyor” is used for
for checking tooth preparation of
abutment teeth for fixed or removal
removal partial dentures. The
quickly and accurately indicates the
planned path of insertion of the
prosthesis intra orally and serves as
visual guide during the preparation
25

23. 26

24. WHAT’S NEW?? - THREE
DIMENSIONAL COMPUTER
AIDED SURVEYING
J Prosthet Dent 2004;92(3):408-412
28

25. • Programs were written
for this technique using
mathematic software
(MatLab:The Math
Works, Inc, Natick,
Mass)
• The program identified
all downward facing
surface triangles on
scan as –ve & upward
facing as +ve, the 29

26. • Tilting the cast
allows for
accurate re-
record of the
new survey line.
• 20˚ tilt
• This can then
be reproduced
onto the digitally30

27. • To reveal favourable and
unfavourable physical characteristics
of the mouth that favour successful
prosthesis design.
• To determine a guided path of
insertion free of interferences
• To determine a design that resists
unseating forces reasonably.
• To delineate unfavourable undercuts 33

28. PATH
OF
INSERT
ION
RETENTIVE
UNDERCUT
S
INTERFERE
NCES
ESTHETICS
GUIDING
PLANES
DESIGN OF
THE
PROSTHESI 34

29. PLATFO
RM
CAST HOLDER/
SURVEYING
TABLE
VERTICAL
ARM
HORIZONTA
L ARM
MAND
REL
SURVEYIN
G ARM
35

30. COMPARISON
NEY’S
SURVEYOR
JELENKO’S
SURVEYOR
WILLIAM’S
SURVEYOR
Horizontal arm
is fixed
Revolves around
vertical arm
Revolves around
vertical arm with a
hinging joint
Surveying arm
is passive
Spring loaded Spring loaded
Surveying arm
secured with
locking device
Spring tension
holds position
Spring tension holds
position
Undercut
gauge-
Fan shaped bead,
each wing differing
Fan shaped bead,
each wing differing
36

31. • Analyzing Rod
• Carbon Marker
• Undercut Gauge
• Wax Trimmer
37

32. 1. Carbon marker
2. Mandrel
3. Analyzing rod
4 – 7. Undercut
Gauge
8. Trimming Knife
BASIC
TOOLS

33. • Used for preliminary survey of the
cast.
• Assessment of degree of undercuts
on hard & soft tissues.
• Assessment of angulation of teeth.
• In distal extension cases, allows
judgement of whether the distal
abutment undercuts are sufficient to
indicate that a tilt may be beneficial.
39

34. • Basically allows visualisation of the
analysing rod’s work.
• Used for drawing survey lines around all
teeth involved in clasp design or that have
proximal undercuts to be eliminated
• To mark the extent of bony/soft tissue
undercuts for prosthetic mouth
preparation if required.
• Light pressure without erosion.
40

35. • Used to measure the location
and horizontal depth of
undercuts on the analysed and
marked teeth in three dimensions
• Stewart-0.01”, 0.015”. 0.02”
• McCracken-0.01”, 0.02’, 0.03”
• Same shank, only the size
• of the tip/bead varies(except 41

36. • Used to trim off excessive wax while
surveying the wax patterns.
• To prevent overcontoured blockout of
unfavourable undercuts.
• To demarcate the exact planned clasp arm
location to be duplicated.
• To create a gap/self cleansing area
using a 25
.
trimmer.
42

37. • Survey lines primarily
stand for the height of
contour of abutment
teeth marked by a
carbon marker during
surveying in a particular
horizontal plane.
• 1916-Prothero’s Cone
Theory 43

38. • Classified as:
High
Medium
Low
Diagonal
Based on Louis
Blatterfein’s division of
abutment teeth into
NEAR ZONE(NZ) &
FAR ZONE(FZ)
J Prosthet Dent
1956;6(3):386-404 44

39. • HIGH SURVEY LINE:
From occlusal 1/3rd in NZ
to occlusal 1/3rd in FZ
• MEDIUM SURVEY LINE:
From occlusal 1/3rd in NZ
to middle 1/3rd in FZ.
• LOW SURVEY LINE: From
cervical 1/3rd in NZ to
cervical 1/3rd in FZ
• DIAGONAL SURVEY 45

40. Typical and atypical types of
survey lines (Blatterfein’s
classification)

41. MEDIUM SURVEY LINE
/TYPICAL LINE:
The line appears on the
buccal or lingual surface
of the tooth
approximately equidistant
from occlusal surface and

42. Diagonal survey line /
Atypical A
• The survey line is in the
occlusal third of the
tooth at the beginning of
the near zone, rapidly
approaches the gingival
margin at the junction of
the far and the near
zones, and is on gingival
margin in the greater
part of the far zone on
the tooth surface.
• Little undercut is present

43. HIGH SURVEY LINE /
ATYPICAL B :
• The survey line is in
occlusal third of both
the near and the far
zones.
• Lingual surfaces of
lower teeth and buccal
surfaces of upper teeth

44. LOW SURVEY LINE
/ATYPICAL C
• The survey line is at the
gingival margin in both
the near and far zones.
• It occurs due to the
marked inclination of the
tooth when it is
associated with a high
survey line.

45. NEY CLASSIFICATION OF
SURVEY LINES
CLASS I : Survey line
runs diagonally
across the tooth
surface.
Type of clasp –
occlusally
approaching cast
clasp with terminal

46. CLASS II :
Survey line
runs
diagonally
across the
tooth surface
but as a mirror
image of Class
I line.
Type of clasp :
gingivally

47. CLASS III :
Survey line
is parallel to
to the
occlusal
surface and
and lies just
just below it

48. Angle of Cervical Convergence
J Dent
2007;4(1): 15-20 55

49. PURPOSES OF A
SURVEYOR
• Surveying of diagnostic cast
• Tripoding of cast
• Surveying the master cast
• Contouring of wax patterns
• Placement of Internal Rest Seats
• Machining of cast restorations
56

50. • To determine the most desirable
path of placement.
• To identify proximal tooth surfaces
that need to be made parallel as that
they act as guiding planes during
placement and removal.
• To locate and measure areas of57

51. • To determine whether tooth and
bony areas of interference will
need to be eliminated
surgically(mouth preparation) or those
that need to be blocked out.
• To identify the height of contour
• To record the cast position in
relation to the selected path of58

52. • A color coding system for the various parts
of the removable partial denture as well as
for other items of information that should
be included on the diagnostic casts helps
prevent confusion on the part of a dental
dental laboratory technician or any one
one trying to understand the design
being proposed.
• There is not at present a universally
accepted color coding system. As result,

53. • Brown crayon pencil out line the
metallic portion.
• Blue crayon pencil out line the acrylic
portion of the denture base.
• Red crayon pencil to indicate areas on
the teeth that will be prepared.
• Solid red rests and rest seats.
 used to
denote the survey lines

55. • Orientation of cast
• Cast tilting
• Visual analysis using analysing rod
• Marking of survey lines /soft tissue undercuts
using carbon markers
• Undercut gauges used to measure amount of
available retention
• Interferences
• Wax Trimmers
• Tripoding of casts
63

56. Orientation of Cast
• Casts oriented such that the anterior part is
always toward the vertical member of
surveyor and away from the operator
• Position for description is fixed for either cast.
• Can be attached to the holding table via:
oSoft plasticine or wax
oLocking screws
engaging the sides of model
oMagnetised iron cast into
base of model
64

57. Cast Tilting
• Tilting is changing the position of the cast,
which thus changes the long axis of each
tooth relative to the horizontal plane.
• Alters the contour, positions, location &
depth of undercut relative to the new plane.
• Allows:
– The most advantageous path of insertion
– Increase in desirable and decrease in
undesirable undercuts
– Distribution of available undercuts to produce 65

58. • Dislodging forces primarily to occlusal
plane.
• Hence, HORIZONTAL or 0
.
TILT most
common(Not>10˚).
• Other tilts:
o Anterior
o Posterior
o Lateral
66

59. ANTERIOR TILT
• In the anterior
tilt, the
anterior teeth
are tilted
downwards.
• The anterior
tilt increase
the mesial 67

60. POSTERIOR TILT
• In the posterior
tilt,the portion
of the cast
tilted
downwards
• The posterior
tilt will
increase the
distal 68

61. LATERAL TILT
• The right lateral tilt
increase undercuts on
buccal surfaces of
right side.
• Buccal under cuts
are reduced on left
side
69
• Left lateral tilt
will increase
undercuts on
buccal surface of
left and will

62. Visual Analysis using
Analysing Rod
• Primarily responsible for “eyeballing”
of the cast.
• Once orientation & tilt is established,
allows for a general tangential
analysis of undercuts, tooth
angulations, etc.
• Also aids the establishment
of relative parallelism of
70

63. Marking of Survey Lines /Soft
tissue Undercuts using Carbon
Markers
• Analysis by the analysing rod is visualised
via the carbon marker.
• 5H pencil graphites secured with metal
reinforcement sheath
71

64. Undercut Gauges used to
measure amount of Available
Retention• These gauges are used to identify the
specific amount and location of
desired retentive undercut on the
surface of the abutment tooth.
• Two types:
– Ney
– Jelenko
• The undercut is best viewed against
light passing through a triangle
bounded by surfaces of
abutment tooth, surveyor blade
,apex being the point of contact at the 72

65. 73

66. • Undercut utilisation
o0.01 → cast retainers
o0.02 → wrought wire retention
o0.03 → rarely used
• If no retentive undercuts are present,
they must be created by:
oGold Crowns
oRetentive Restorations
oCreating an undercut by tooth
modification 74

67. Interferences
• Seen in both maxilla & mandible
• Maxilla:
oTorus Palatinus-surgical removal
advised, tilting does
not provide relief
oBuccally Tipped Teeth-
Tilting+Recontouring
• Mandible:
oTorus Mandibularis
Labial Bar
75

68. Wax Trimmers
• Once unfavorable undercuts are blocked,
to prevent overcontouring, wax trimmers
are used.
• In case of distal extension cases, to create
a gap/self cleansing area under the
saddle, a 25
.
trimmer is used in
conjunction.
• Wax patterns for casting can also be
carved accordingly.
76

69. Tripoding of Casts
• Once all this is done,
the final cast position
must be recorded so
that the cast may later
be repositioned
precisely. This
procedure is referred
to as TRIPODING.
• Seven primary
methods.
J Prosthet Dent
1976;35(4):267-269 77

70. • METHOD 1
– Three cross marks (each
line 3mm wide) / dots on the
tissue portion of the cast,
lingual to the teeth, at widely
apart points with vertical arm
of the surveyor maintained at
fixed position
– Marks encircled with
coloured pencil for easy
identification.
– Marker tip to be trimmed at
45. 78

71. • METHOD 2
–Scour 2 sides and the
dorsal aspect of the
base of the cast with a
sharp instrument/
marking pencil held
against the surveyor
blade.
–Marks don’t interfere
with the design
–Easy duplication 79

72. • METHOD 3
– A hole about 10 mm in
diameter and 10 mm deep
is prepared in the lingual
land area of the
mandibular cast with a
large acrylic finishing bur.
– The pin is locked in the
vertical spindle and lowered
to the bottom of the hole.
– The vertical spindle with
the pin is then locked in
this position and the hole is
filled with dental plaster. 80

73. • METHOD 4
–An instrument
reproduces the tilt of
a cast on a surveyor
using protractor
–Flat metal strip 5mm
wide and 3cm long,
one end of which
bend upward at 90˚
–Metal rod is attached
to the end of the flat
part of the strip which
J Prosthet Dent 1965;34(3)465-471
81

74. • A hole is tapped and
threaded in the middle of
the bent part of metal
strip through which a
protractor is screwed
• The protractor can rotate
around the metal rod,
acting as a pointer.
• After determining the
path of insertion, the
protractor instrument
is mounted on the
surveyor in place of 82

75. • METHOD 5
–Make a hole in the
tongue space on
mandibular cast 4-
6mm in diameter
–Hole should create
undercut but should
not perforate the
base of the cast
–Following normal
surveying J Prosthet Dent 1981;41(3):352-354
83

76. • With the bur in
place, fill the hole
with
autopolymerizing
acrylic resin
• For reorientation,
reposition the bur in
autopolymerizing
resin for a parallel
84

77. • METHOD 6
–Wax deposited
on side of cast
at 3 widely
separated
points
–Analyzing rod
used to create
imprints of
wax
J Prosthet Dent 1991;61(5):378-380
85

78. • METHOD 7
–Make a universal tray
on a cast after
adapting 2 thickness
of baseplate wax
over the teeth.
–Make a platform with
a cylinder over the
tray and insert
analyzing rod into
cylinder.
–Move the tray to and
J Prosthet Dent 1997;72(1):104
86

79. • Tray loaded with elastic
impression material,
the cylinder is attached
to the rod and locked
• After establishing tilt,
an impression is
made
• Reorientation can later
be done by placing the
impression on cast and
87

80. • Surveyed as a new cast
• Prepared proximal guiding plane surfaces
will indicate the correct anteroposterior tilt
• Any remaining interferences after mouth
preparation must be eliminated with block
out.
• Survey lines marked
88

81. Surveying in Confined
Areas
89
J Prosthet Dent 1991;61(5):378-380

82. • Orthodontic wire
can be used as a
horizontal "feeler
gauge“ in
combination with
the vertical
analyzing wire to
estimate the
adequacy of the
retentive
undercut. 90

83. Contouring of Wax
Patterns
•Surveyor blade – used as wax carver
•Proposed path of placement maintained
throughout preparation of cast restorations for
abutment teeth.
•Surfaces of restorations that provide
reciprocation for clasp arms have to be
contoured to permit their location well below
occlusal surfaces and on non retentive areas
91

84. BLOCK OUT
• After the establishment of path of insertion
and the location of undercut areas on the
master cast, the areas that shall be crossed by
the rigid parts of the denture must be blocked
out.
• Roach carver or No.7 spatula used to adapt
the blocking wax.
• Four types:
o Parallel Blockout
o Shaped Blockout/Ledge Blockout
o Arbitrary Blockout
o Relief
92

85. • Parallel Blockout:
– Performed:
oOn interproximal surfaces to be used as
guiding planes(0/2/6˚ taper)
oBeneath all minor connectors
oOn tissue undercuts to be crossed by rigid
connectors
oBeneath bar clasp arms to gingival crevices
– Materials Used:
oHard baseplate wax
oHard inlay wax
oOil based modelling clay
– Thickness-Only undercut remaining gingival
to contact of surveyor blade with tooth surface
93

86. • Shaped/Ledge Blockout:
–Performed:
oOn buccal & lingual surfaces to
locate plastic or wax patterns for
clasp arms
–Material:
oHard Baseplate Wax
–Thickness: Ledges for location of
reciprocal clasp arms to follow
height or convexity so that they
may be placed as cervical as 94

87. • Arbitrary Blockout:
–Performed:
oOn all gingival crevices
oOn gross tissue undercuts below areas
involved in framework design
oOn tissue undercuts distal to cast framework
oLabial & buccal tooth undercuts not involved in
denture design
–Material:
oOil Based Modelling Clay
oHard Baseplate Wax
–Thickness:Enough to just eliminate gingival95

88. • Relief
–Provided:
o Beneath lingual bar connectors or the bar portion
of linguoplates
oOn areas in which the major connector will
contact thin tissue
oBeneath framework extensions onto ridge
areas for attachment of resin bases
–Material:
oAdhesive wax
oHard Baseplate Wax
–Thickness:
o32 gauge wax(universally) 96

89. Placement of Internal
Rest Seats
• Large box shaped metallic extensions that
function as intracoronal extensions.
• Carved in wax patterns and refined further
with hand piece after casting.
97

90. Machining of Cast
Restorations
• Rotary instruments can be attached to the
surveyor via a handpiece holder for
trimming/machining of restorations.
• Surveying arm can then be rotated around
the restoration to trim excess crown material.
98

91. 99

92. 100
Novel 3D Modeling Technique of Removable Partial Denture Framework
Manufactured by 3D Printing Technology
This study was carried out to digitize the removable partial denture framework
construction using a combination of simplified novel modeling technique and a 3D
printing prototyping technology.
Dr. Mostafa Omran Hussein1, Dr. Lamis
Ahmed Hussein2

93. 101

94. 102

95. 103

96. 104
The record of path of insertion on the dental cast is part of the
dentist«SQ»s work authorization to the dental laboratory
technician for a removable partial denture. Through the years
several methods have been suggested to record and transfer
the achieved path of insertion.
In this article a simple attachment to the surveyor is explained
which can make the recording and transfer easy and repeatable
at all situations.

97. 105

98. 106

99. 107
ADVANTAGES
1.Freedom to select the points, which need not
be present in a single plane.
2.Easy and less time consuming for
reorientation.
3.Accurate lab authorization.
4.Can also be used to assess the path of
insertion if measuring rods are replaced with
analyzing rods.
5.Use of this instrument can eliminate many
errors that may happen during lab authorization.

100. 108
A procedure for recording and reproducing the cast
position on a surveyor
This article describes a simple and effective method for
recording the cast orientation on the surveyor table
and reproducing this orientation to multiple casts using
an acrylic resin index.

101. 109
(a) Put the teeth occlusal surfaces on the doughy acrylic resin; (b) The acrylic resin
occlusal index; (c) The analyzing rod is placed into the hole on the back side of the
occlusal index

102. SUMMARY &
CONCLUSION
110
Treatment planning of a removable partial
denture with the use of a dental surveyor
helps in the analysis & planning of the
denture design and accomplishment of tooth
modifications (preparation) and delineates
proper clasp placement that is critical for
optimum stability and retention and are
strongly necessary for successful favourable
fabrication of the prosthesis.

103. REFERENCES
• Brown DT, Carr AB. McCracken’s Removable
Partial Prosthodontics. 12th ed. St.Louis: Mosby;
2011
• Lammie GA, Osborne J. Partial Dentures. 4th ed.
Michigan: Blackwell; 2009
• Miller EL. Removable Partial Prosthodontics. 6th
ed. Baltimore: Wilkins; 2006
• Cagna DR, DeFreest CF, Phoenix RD. Stewarts
Clinical Removable Partial Prosthodontics. 4th
ed. Toronto:Quintessence;2008
• Engelmeier RL. The History and Development of111

104. • Engelmeier RL. The History and Development of
the Dental Surveyor: Part II. J Prosthodont
2002;11(1):122-130
• Engelmeier RL. The History and Development of
the Dental Surveyor: Part I. J Prosthodont 2004;
13(1): 195-202
• Jerome R. Tabbot MK. Three dimensional
computer aided surveying. J Prosthet Dent
2004;92(3):408-412
• Matthews CL, Philip R. Survey lines in
removable partial denture design. J Prosthet
Dent 1956;6(3):386-404
• Eghlim L, Geramy A. The Influence of Angle of 112

105. • Prentiss AL, Vockhardt M. Technique for
maintaining cast relation to surveyor for
reproduction of record. J Prosthet Dent
1965;34(3):465-471
• Jacob BS. Acrylic Bead Method for reorientation
of Master Casts. J Prosthet Dent
1981;41(3):352-354
• Arthur JM. Reinstating techniques for tripoding. J
Prosthet Dent 1991;61(5):378-380
113

106. 114