SURVEYORS & SURVEYING PROCEDURES

1. 1Surveyors & Surveying Procedures-67

2. 2Surveyors & Surveying Procedures-67

3. • Introduction
• Historical Perspective
• Definitions
• Objectives of Surveying
• Parts of a Surveyor
• Surveying Tools
• Survey Lines
• Purposes of Surveyors
• Summary & Conclusion
• References
3Surveyors & Surveying Procedures-67

4. • 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. 4Surveyors & Surveying Procedures-67

5. • 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 5Surveyors & Surveying Procedures-67

6. • 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
6Surveyors & Surveying Procedures-67

7. >The Electrome >The Retentoscope
>The Stressograph
>Broken-arm > Pendulum Surveyor
>Optical
Surveyor
7Surveyors & Surveying Procedures-67

8. MICROSURVEYOR
• Hand held surveyor
• Establishes path of insertion by tilting
vertical arm hinged at the base/platform
• Collapsible into individual parts for easy
storage
Surveyors & Surveying Procedures-67 8

9. WHAT’S NEW?? - THREE
DIMENSIONAL COMPUTER
AIDED SURVEYING
J Prosthet Dent 2004;92(3):408-412
9Surveyors & Surveying Procedures-67

10. • 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 10Surveyors & Surveying Procedures-67

11. • Tilting the cast
allows for accurate
re-record of the new
survey line.
• 20˚ tilt
• This can then be
reproduced onto the
digitally scanned
tooth structure.
11Surveyors & Surveying Procedures-67

12. • SURVEY-”The procedure of locating or
delineating the contour and position of the
abutment teeth and associated structures
before designing a partial denture.”-GPT 8
• SURVEYING-”An analysis and comparison
of the prominence of intraoral contours
associated with the fabrication of a
prosthesis”-GPT
• SURVEYOR-”An instrument used in the
construction of a removable partial denture to12Surveyors & Surveying Procedures-67

13. • SURVEY LINE-”A line drawn on a tooth or
teeth of a cast by means of a surveyor for
the purpose of determining the positions of
the various parts of a retainer”-GPT 8
• GUIDING PLANE-”Two or more vertically
parallel surfaces of abutment teeth so
oriented as to direct the path of
placement/removal of a removable partial
denture”-GPT 8
• PATH OF INSERTION-”The direction in
which a prosthesis is placed upon and
removed from the abutment teeth”-GPT 8
13Surveyors & Surveying Procedures-67

14. • 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 for
mouth preparation.
14Surveyors & Surveying Procedures-67

15. PATH
OF
INSERT
ION
RETENTIVE
UNDERCUT
S
INTERFERE
NCES
ESTHETICS
GUIDING
PLANES
DESIGN OF
THE
PROSTHESI 15Surveyors & Surveying Procedures-67

16. PLATFO
RM
CAST HOLDER/
SURVEYING
TABLE
VERTICAL
ARM
HORIZONTA
L ARM
MAND
REL
SURVEYIN
G ARM
16Surveyors & Surveying Procedures-67

17. 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
17Surveyors & Surveying Procedures-67

18. • Analysing Rod
• Carbon Marker
• Undercut Gauge
• Wax Trimmer
18Surveyors & Surveying Procedures-67

19. • 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.
19Surveyors & Surveying Procedures-67

20. • 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.
20Surveyors & Surveying Procedures-67

21. • 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 Neys).
21Surveyors & Surveying Procedures-67

22. • Used to trim off excessive wax while
surveyin 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.
22Surveyors & Surveying Procedures-67

23. • 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
• 1955-DeVan-Suprabulge & Infrabulge
23Surveyors & Surveying Procedures-67

24. • 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 24Surveyors & Surveying Procedures-67

25. • 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 25Surveyors & Surveying Procedures-67

26. Angle of Cervical Convergence
J Dent
2007;4(1): 15-20 26Surveyors & Surveying Procedures-67

27. 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
27Surveyors & Surveying Procedures-67

28. • 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 of teeth that
28Surveyors & Surveying Procedures-67

29. • 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 of placement for future
references 29Surveyors & Surveying Procedures-67

30. • 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
30Surveyors & Surveying Procedures-67

31. 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:
o Soft plasticine or wax
o Locking screws engaging the sides of model
o Magnetised iron cast into base of model
31Surveyors & Surveying Procedures-67

32. 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
more uniform retention throughout the available
teeth & tissues 32Surveyors & Surveying Procedures-67

33. • Dislodging forces primarily to occlusal
plane.
• Hence, HORIZONTAL or 0
.
TILT most
common(Not>10˚).
• Other tilts:
o Anterior
o Posterior
o Lateral
33Surveyors & Surveying Procedures-67

34. 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 various planar surfaces.
34Surveyors & Surveying Procedures-67

35. 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
35Surveyors & Surveying Procedures-67

36. 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 height of
convexity and base of triangle being
36Surveyors & Surveying Procedures-67

37. • Undercut utilisation
o 0.01 → cast retainers
o 0.02 → wrought wire retention
o 0.03 → rarely used
• If no retentive undercuts are present, they must
be created by:
o Gold Crowns
o Retentive Restorations
o Creating an undercut by tooth modification
37Surveyors & Surveying Procedures-67

38. Interferences
• Seen in both maxilla & mandible
• Maxilla:
o Torus Palatinus-surgical removal advised,
tilting does not provide relief
o Buccally Tipped Teeth-Tilting+Recontouring
• Mandible:
o Torus Mandibularis
o Lingually Tipped Teeth
Labial Bar
38Surveyors & Surveying Procedures-67

39. 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.
39Surveyors & Surveying Procedures-67

40. 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 40Surveyors & Surveying Procedures-67

41. • 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. 41Surveyors & Surveying Procedures-67

42. • 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
– May get smudged upon
handling
42Surveyors & Surveying Procedures-67

43. • 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. 43Surveyors & Surveying Procedures-67

44. • 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 serves to fit
the instrument to the
surveyor
J Prosthet Dent 1965;34(3)465-471
44Surveyors & Surveying Procedures-67

45. • 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 analyzing rod
• 3 divergent points are 45Surveyors & Surveying Procedures-67

46. • 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 procedures,
a parallel shanked
straight handpiece bur
is suspended.
J Prosthet Dent 1981;41(3):352-354
46Surveyors & Surveying Procedures-67

47. • With the bur in place, fill
the hole with
autopolymerizing acrylic
resin
• For reorientation,
reposition the bur in
autopolymerizing resin
for a parallel tripod
record.
47Surveyors & Surveying Procedures-67

48. • METHOD 6
– Wax deposited on
side of cast at 3
widely separated
points
– Analyzing rod used to
create imprints of wax
– This can be
transferred by
duplication
J Prosthet Dent 1991;61(5):378-380
48Surveyors & Surveying Procedures-67

49. • 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
fro vertically during
setting of the material
to make a smooth
J Prosthet Dent 1997;72(1):104-107
49Surveyors & Surveying Procedures-67

50. • 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
the tilt at which the
stylus can enter the
cylinder locks the prior 50Surveyors & Surveying Procedures-67

51. • 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
51Surveyors & Surveying Procedures-67

52. Surveying in Confined
Areas
52Surveyors & Surveying Procedures-67
J Prosthet Dent 1991;61(5):378-380

53. • 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.
• Dimensions of the wire
allow for finer
measurements.
53Surveyors & Surveying Procedures-67

54. 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
54Surveyors & Surveying Procedures-67

55. 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
55Surveyors & Surveying Procedures-67

56. • 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 surface56Surveyors & Surveying Procedures-67

57. • 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
possible without becoming retentive
57Surveyors & Surveying Procedures-67

58. • 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 gingival
crevice, levelled arbitrarily with a wax spatula
58Surveyors & Surveying Procedures-67

59. • Relief
– Provided:
oBeneath 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)
o20 gauge wax for resin base attachment relief
59Surveyors & Surveying Procedures-67

60. 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.
60Surveyors & Surveying Procedures-67

61. 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.
61Surveyors & Surveying Procedures-67

62. Surveyors & Surveying Procedures-67 62

63. SUMMARY &
CONCLUSION
63Surveyors & Surveying Procedures-67
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.

64. 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 of64Surveyors & Surveying Procedures-67

65. • 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 65Surveyors & Surveying Procedures-67

66. • 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
66Surveyors & Surveying Procedures-67

67. 67Surveyors & Surveying Procedures-67