1. INTRODUCTION 2. DEFINITIONS 3. HISTORY 4. TYPES 5. COMPARISON OF 3 SURVEYORS 6. OBJECTIVES 7. PRINCIPLE 8. USES 9. PARTS 10. SURVEY LINES 11. SURVEY PROCESS 12. RECENT ADVANCES 13. SUMMARY & CONCLUSION 14. REFERANCES

1. SURVEYOR
&
SURVEYING
Dr. Shweta Pandey
PG 1st yr
GDC Indore

2. CONTENT
2

3. INTRODUCTION 1

4. INTRODUCTION
▸ A partial denture will not succeed unless it is designed and constructed in harmony with all
the physiologic and mechanical problems present in the patient's mouth.
▸ Surveying and designing are important steps towards achieving a successful restoration.
▸ A well-executed design serves as a blueprint for fabrication of the removable partial
dentures.
▸ Lack of plan, haphazard preparation and lack of abutment preparation are a few factors of
partial denture failure
4

5. DEFINITIONS 2

6. 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
SURVEYOR
An instrument used in the construction of are movable partial denture to locate and delineate the contours and
relative positions of abutment teeth and associated structures.
GPT 8
SURVEYING
An analysis and comparison of the prominence of intraoral contours associated with the fabrication of a
prosthesis.
GPT 8

7. 7
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
HEIGHT OF CONTOUR
A line encircling a tooth designating its greatest circumference at a selected position
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

8. HISTORY
&
DEVELOPMENT
3

9. 9
▸ First part of the twentieth century,
most removable partial dentures were
designed and constructed using
arbitrary technique of “EYEBALLING”
▸ Turning point in removable partial
denture service occurred in 1918
▸ Dr A. J. Fortunati introduced the dental
surveyor.
DR. W. M. RANDALL’S TECHNIQUE

10. 10
EARLY PARALLELING INSTRUMENTS
EARLY PARALLELING INSTRUMENTS
Chayes Parallelometer
soldering jig for
Griswold attachment system

11. 11
Robinson surveyor Hanau’s “dental surveying apparatus.

12. original Ney surveyor
1923
Weinstein and Roth
current model of the Ney surveyor
1937
Modified Ney Surveyor

13. 13
Wills surveyor
1937
Jelenko surveyor
Original Wills surveyor
1929

14. 14
Kings College surveyor
1940
electronic surveyor
1958
Columbia Parallelor
1940
Roach surveyor

15. BROKEN-ARM SURVEYORS
15
Retentoscope Stressograph Harvey surveyor Hagman Balancer surveyor

16. 16
Ticonium Company
Broken-arm dental surveyor
Bego Paraflex surveyor
Williams Gold Refining Company
broken-arm surveyor
Nesor broken-arm surveyor

17. BLOCKOUT INSTRUMENTS
17
Austenal Surveyor Austenal Micro Analyzer Paratherm surveying

18. MILLING MACHINES
18
A.(A) Chayes milling machine
B.(B) Austenal precision milling machine
C.(C) Galloni Isoparallelometer
D.(D) Kavo precision dental milling
machine
(A) Frey milling
A.(B) Bachman parallelometer
B.(C) Fa¨h parallelometer with cross-table
C.(D) Albrecht Linear Motor Milling

19. MICROSURVEYOR
▸ Hand held surveyor
▸ Establishes path of insertion by
tilting vertical arm hinged at the
base/platform
▸ Collapsible into individual parts for
easy
19

20. HIGHRISER RPD SURVEYOR
20
▸ Is a pendulum arm Block out/Survey Instrument.
▸ The innovative design concept allows fluid
movement.
▸ Arm can be secured to maintain it at a set vertical
height
▸ The arm can easily turn back and forth, twist, or
move up or down
▸ Spring tension is easily adjusted to individual
preference.
▸ Heating element attachment is created for simple
use, and various size tips are available.
▸ A lead holding chuck accepts a full four-inch lead
instead of the customary short pieces.

21. SKYSCRAPER SURVEYOR
▸ It is a dual pendulum Electronic
Block out / Survey Instrument.
▸ The dual-arm system has several
advantages;
▹ -The heating element need
not be removed when
surveying;
▹ -By simply rotating the
column, the modern tool is
available for use
21

22. THERMA-SCULPT
SURVEYOR ATTACHMENT
▸ It is an electronically heated arbor that can be
easily to Ney-Jelenko type surveyor.
▸ The design concept enables the technician to
produce
▸ wax sculpting businesses: from block out of
RPD,
▸ attachment and implant procedures.
▸ Capabilities:
▹ Constant temperature control allows
faster, consistent and predictable
results
▹ sculpt the wax, not just melt it
▹ It takes only seconds to install or remove
▹ Eliminates the need for bunsen burner or
alcohol torching of block-out too
22

23. RECENT INOVATIONS

24. INTRA-TEK, DALLAS, TX
SURVEYOR
▸ A beam of laser light projects
vertically downward from distal
end of horizontal arm to same as
surveyor arm, the laser light is
visible only above the height of
contours, where as the undercut
below it is cast in a dark shadow.
24

25. 3D COMPUTER AIDED
SURVEYOR
▸ Programs were written for this technique
using mathematic software
▸ (MatLab; The MathWorks, Inc, Natick, Mass)
▸ that reads the triangular facetted surface
models (using the STL file format)
25

26. 26

27. OPTICAL SURVEYOR
▸ parallel light beams
▸ Light bulbs with dense filaments & condenserlenses
▸ Contained in a box.
▸ Advantages:
▹ Changes in survey lines & undercut can beinspected easily.
▹ Better visualization Disadvantages
▸ Disadvantages:
▹ Requires dark room
▹ Light beams reflecting from cast can pose problems in
illumination
27

28. INTRA-ORAL SURVEYORS
▸ For checking tooth preparation of abutment teeth for
fixed/removable partial dentures.
▸ Accurately indicates planned path of insertion.
▸ Visual guide during tooth preparation.
▸ Inexpensive, practical & readily available method.
28

30. OBJECTIVES OF SURVEYING
▸ 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.
30

31. PARTS OF SURVEYOR
A. Platform on which the base is moved
B. Vertical arm that supports the superstructure
C. Horizontal arm from which the surveying tool
suspends
D. surveying arm
E. Mandrel for holding special tools
F. Table to which the cast is attached
G. surveying table
31

32. 32
NEY’S SURVEYOR
Horizontal arm is fixed
Surveying arm is passive
Surveying arm secured
with locking device
Undercut gauge-
JELENKO’S SURVEYOR
Revolves around vertical arm
Spring loaded
Spring tension
holds position
Fan shaped bead,
leach wing differing
WILLIAM’S SURVEYOR
Revolves around vertical
arm with a hinging joint
Spring loaded
Spring tension holds
position
Fan shaped bead,
leach wing differing

33. 33
• NEY’S SURVEYOR
• Horizontal arm is fixed
• Surveying arm is passive
• Surveying arm secured with
locking device
• cast table is moved around
surveyor platform
• JELENKO’S SURVEYOR
• Revolves around vertical arm
• Surveying arm Spring loaded
• Surveying arm secured with
Spring tension holds position
• cast table is fixed
• WILLIAM’S SURVEYOR
• Revolves around vertical arm with a hinging joint
• Spring loaded
• Surveying arm secured with Spring tension holds
• position
• cast table is moved around surveyor platform
COMPARISON

34. SURVEYING TOOLS
34
Analyzing
Rod
Carbone
Marker
Depth Gauge Wax Trimmer
Surveying Blade Used For Trimming Blockout Tapered tools, 2- and 6-degree

35. SURVEY LINE
▸ 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- Supra-bulge & Infra-bulge
35

36. SIGNIFICANCE OF SURVEY LINE
▸ rigid, nonflexible part of the prosthesis must be designed to lie above the
survey line.
▸ flexible parts may be designed to go below survey line.
▸ only terminal third of retentive clasp is placed gingival to survey line.
▸ To locate areas of undesirable tooth undercuts that must be avoided or
eliminated by contouring or placing restoration on the teeth.
36

37. TYPES OF SURVEY LINE
▸ According to Blatterfein
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
Fromocclusal 1/3rd in NZ to gingival 1/3rd inFZ
37

38. NEY'S CLASSIFICATION
▸ CLASS I
Survey line runs diagonally across the tooth surface. The type of clasp
indicated is occlusally approaching cast clasp with terminal third engaging
the undercut.
▸ CLASS II
Survey line also runs diagonally across the tooth surface but as a mirror
image of Class I line. Here a gingivally approaching clasp arm is suggested
▸ CLASS III
Survey line is parallel to the occlusal surface and lies just below it.
38

39. PATH OF INSERTION
▸ The path pursued by the denture from its initial contact with the teeth until it is
fully seated. This path corresponds with the path of withdrawal and may or may
not correspond with the path of displacement.
▸ single path of insertion ---Enough guide surfaces are contacted by the denture
▸ Multiple paths of insertion--- Guide surfaces are not employed
Abutment teeth are divergent
39

40. FACTORS THAT DETERMINE PATH OF PLACEMENT
40
Retentive
Areas
Interferance
Esthetics
Guiding
Plane

41. RETENTIVE UNDERCUTS
▸ retentive undercuts must be present on the abutment teeth
when the cast displays a horizontal tilt.
▸ because dislodging forces are always directed perpendicular
to the occlusal plane
▸ If retentive undercuts are not present they must be created
▹ full crown or porcelain bonded to metal
▹ Enamel surfaces are contoured in limited circumstances
to provide or improve retentive undercuts
▸ Ideally - 0.010-inch undercut at the most desirable location.
▹ Mesio buccal line angle, the distobuccal line angle, or the
midfacial surface
▸ wrought-wire clasp is planned, a retentive undercut of 0.015
41

42. ▸ Tilt may be changed to optimize the undercut on any
tooth
▸ Tilt is normally changed so that a retentive clasp will
be positioned no farther occlusally or incisally than
the junction of the gingival and middle thirds of the
tooth.
▹ more esthetic result
▹ decrease the torquing forces transmitted to the
abutment.
42

43. INTERFERANCE
▸ Teeth, bony prominences, soft tissue undercuts, and exostoses
▹ changing the tilt of the cast on the surveying table.
▹ surgical intervention
INTERFERENCES IN THE MAXILLARY ARCH
▸ palatal torus
▸ Exostoses and undercuts -increased accumulation of food
beneath the denture base, and decreased denture stability
43

44. 44
 Facial tipping of posterior teeth
• positioning the buccal clasp arm more difficult for esthetic and mechanical
reasons.
• Because the clasp arm must be placed farther from the rotational center of the
tooth
• lever arm is longer, and the resultant forces are likely to be more damaging

45. INTERFERENCES IN THE MANDIBULAR ARCH
▸ Mandibular tori
▹ compromise the thickness of the major connector
▹ interfere with the activities of the tongue and the movable
floor of the mouth
▸ Lingual tipping
▹ no undercuts on their facial surfaces and large undercuts
on their lingual surfaces
▹ labial bar major connector instead of a lingual bar or lingual
plate
▹ placing restorations to eliminate the offending undercuts
▹ orthodontic movement of the teeth
45

46. ▸ Areas adjacent to the pear-shaped pads
▹ UNILATERAL - slight lateral tilt of the surveying table
may eliminate the undercut
▹ BIILATERAL- tilting the surveying table will have little
effect.
▸ Bony prominences
▹ mandibular canines and premolars.
▹ produce soft tissue undercuts
▹ interfere with the placement of denture bases and
infra-bulge clasps
▹ lateral tilt of the cast may eliminate such
interferences
46

47. ESTHETICS
▸ To obtain optimum esthetics
▹ metal components must be concealed as effectively as possible,
▹ prosthetic teeth must be selected, appropriately contoured, and
properly positioned
▸ Large undercuts on the proximal surfaces of anterior
teeth
▹ modifying the tilt of the cast
▹ reshaping the proximal surfaces of teeth
47

48. GUIDING PLANE
▸ Guiding planes are formed from the proximal tooth surfaces of the
teeth and are contacted by the minor connectors or other rigid
components of the partial denture.
▹ These planes guide the prostheses for removal and placement.
▹ The guiding planes are in intimate contact with the minor
connectors, help to stabilize against the lateral forces.
▹ protect the weakened teeth from destructive forces
▸ surveyor is used to locate the potential surfaces of the teeth that can
be converted to guiding planes by selective grinding
▸ wax patterns should beshaped by the surveyor with their surfaces
parallel to the path of insertion.
48

49. USES

50. Uses of a Dental Surveyor
▸ Surveying the Diagnostic Cast
▸ Tripoding the Cast
▸ Contouring Wax Patterns
▸ Surveying Ceramic Veneer Crowns
▸ Machining Cast Restorations
▸ Placement of Intra-coronal Retainers (Internal Attachment)
▸ Placement of Internal Rest Seats
▸ Surveying the Master Cast
50

51. OBJECTIVES OF SURVEYING DIAGNOSTIC CAST
▸ To determine the most desirable path of placement.
▸ To identify proximal tooth surfaces that are or need to be made parallel
▸ To locate and measure areas of the teeth that may be used for retention
▸ To determine whether teeth and bony areas of interference need to be eliminated surgically
or by selection of a different path of placement
▸ To determine the most suitable path of placement that permits locating retainers and
artificial teeth to provide the best esthetic advantage
▸ To permit accurate charting of the mouth preparations to be made
▸ To delineate the height of contour on abutment teeth and to locate areas of undesirable tooth
undercut that are to be avoided, eliminated, or blocked out
▸ To record the cast position in relation to the selected path of placement for future reference:
51

52. STEP-BY-STEP PROCEDURES IN
SURVEYING A DIAGNOSTIC CAST
▸ 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
52

53. ORIENTATION OF CAST
▸ Casts oriented such that the anterior part is always
toward the vertical member of surveyor and away
from the operator.
▸ Can be attached to the holding table via:
▹ Soft plasticine or wax
▹ Locking screws engaging the sides of model
▹ Magnetised iron cast into base of model
53

54. 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 of survey line 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
▹ Establishes parallelism & improvises upon esthetics
54

55. BASIC CAST TILTS
▸ Dislodging forces primarily to
occlusal plane.
▸ Hence, HORIZONTAL or 0 TILT most
common (Not>10").
▸ Other tilts:
▹ Anterior
▹ Posterior
▹ Lateral
55

56. 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.
56

57. MARKING OF SURVEY LINES /SOFT
TISSUEUNDERCUTS USING CARBON MARKERS
▸ Analysis by the analysing rod is
visualized via the carbon marker
▸ 5H pencil graphites secured with
metal reinforcement sheath
57

58. UNDERCUT GAUGES USED TO MEASURE AMOUNT OF
AVAILABLE RETENTION
▸ Gauges are used to identify the specific amount
and location of desired retentive undercut on the
surface of the abutment tooth.
▸ 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 the gingival tissues.
58

59. ▸ Undercut utilization
▹ 0.01 -cast retainers
▹ 0.02-> wrought wire retention
▹ 0.03 — rarely used
▸ If no retentive undercuts are present, they must be
created by
▹ Gold Crowns
▹ Retentive Restorations
▹ Creating an undercut by tooth modification
59

60. WAX TRIMMERS
▸ Once unfavorable undercuts are blocked, to
prevent over contouring 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
60

61. PRESERVING THE TILT THROUGH
TRIPODING
▸ Once tilt has been selected for given RPD design, this tilt
should be preserved, so that it can be re-established
accurately to the surveying table. This procedure is
termed as "TRIPODING".
▸ This helps in returning the cast to the surveyor for future
reference.
▸ For purposes of tripodization, the 0.030-inch undercut
gauge is used
61

62. 62

63. Methods for tripoding a cast
METHOD 1
▸ By placing widely spaced dots on the tissue
surface of the cast using the tip of the
carbon marker, with the vertical arm of the
surveyor in a locked position
63

64. 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
64

65. 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.
▸ Once the plaster is set, vertical spindle is released from
cemented pin
65

66. ▸ 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 a round 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 marked, with readings recorded at each
tilt
66

67. 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
67

68. 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.
▸ With the bur in place, fill the hole with auto polymerizing
acrylic resin
▸ For reorientation, reposition the bur in autopolymerizing
resin for a parallel tripod record.
68

69. 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
69

70. 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 vertical perforation in
cylinder.
70

71. ▸ 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 position
71

72. CONTOURING WAX PATTERNS
▸ surveyor blade is used as a wax carver
▸ proposed path of placement may be maintained
throughout the preparation of cast restorations
for abutment teeth
▸ Those surfaces of restorations that are to
provide retention for clasp arms should be
contoured
72

73. SURVEYING CERAMIC VENEER CROWNS
Before final glaze abutment crowns should be
surveyed on a full arch cast to ensure the correct
contour of the veneered portions or to locate those
areas that need recontouring.
MACHINING CAST RESTORATIONS
73

74. PLACEMENT OF INTRA-CORONAL RETAINERS
(INTERNAL ATTACHMENT)
▸ To select a path of placement.
▸ estimating the proximity of the recess to the pulp.
▸ To carve recesses in wax patterns, to place internal attachment trays in wax
patterns, or to cut recesses in castings with the handpiece holder.
▸ To place the keyway portion of the attachment in the casting before
investing and soldering; each keyway must be located parallel to the other
keyways elsewhere in the arch.
74

75. PLACEMENT OF INTERNAL REST SEATS
Internal rest seats carved in the wax patterns and further
refined with the handpiece after casting.
75

76. SURVEYING MASTER CAST
▸ To select the most suitable path of placement by following mouth preparations that
satisfy the requirements of guiding planes, retention, noninterference, and esthetics.
▸ To permit measurement of retentive areas and to identify the location of clasp terminals
▸ To locate undesirable undercut areas that will be crossed by rigid parts of the restoration
during placement and removal
▸ To trim blockout material parallel to the path of placement before duplication.
76

77. BLOCKING OUT THE MASTER CAST
▸ any undercut areas that will be crossed by rigid parts of
denture must be eliminated by blockout.
TYPES
▸ Paralleled Blockout
▸ Shaped Blockout
▸ Arbitrary Blockout
▸ Relief
77

78. 78
SITE
• Proximal tooth surfaces to
be used as guiding planes
• Beneath all minor
connectors
• Tissue undercuts to be
crossed by rigid
connectors
• Tissue undercuts to be
crossed by the origin of
bar clasps
• Deep interproximal spaces
to be covered by minor
connectors or linguo plates
• Beneath bar clasp arms to
gingival crevice
MATERIAL
• Hard Baseplate wax or
blockout material
THICKNESS
• Only undercut remaining
below contact of the
surveyor blade with tooth
surface
PARALLELED BLOCKOUT

79. 79
SHAPED BLOCKOUT
SITE
• On buccal and
lingual surfaces to
locate plastic or
wax patterns for
clasp arms
MATERIAL
• Hard 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

80. 80
ARBITRARY BLOCKOUT
SITE
• All gingival crevices
• Gross tissue undercuts
situated below
• areas involved in the
design of denture
• framework
• Tissue undercuts distal
to the cast frame-
• work
• Labial and buccal tooth
and tissue under-
• cuts not involved in
denture design
MATERIAL
• Hard baseplate wax or
oil-based clay
THICKNESS
• Enough to just eliminate
gingival crevice
• Leveled arbitrarily with a
wax spatula
• Smoothed arbitrarily with
a wax spatula
• Filled & tapered with
spatula to within the
upper third or crown

81. 81
RELIEF
SITE
• Beneath lingual bar
connectors or the bar portion
of the linguoplates when
indicated
• Areas in which major
connectors will contact thin
tissue, such as hard areas so
frequently found on lingual or
mandibular ridges and
elevated palatal raphes
• Beneath framework
extensions onto ridge areas
for attachment of resin bases
MATERIAL
• Adhesive wax sealed to the
cast; should be wider than the
major connector to be placed
on it
• Hard baseplate wax
• Adhesive wax, well adapted to
and sealed to the cast beyond
the involved area
THICKNESS
• 32-gauge wax if the slope of
the lingual alveolar ridge is
parallel to the path of
placement; 32-gauge wax
after parallel blockout of
undercuts if the slope of the
lingual alveolar ridge is
undercut to the path of
placement.
• Thin layer flowed on with hot
wax spatula; however, if the
maxillary torus must be
covered, the thickness of the
relief must represent the
difference in the degree of
displacement of the tissues
covering the torus and the
tissues covering the residual
ridges 20-gauge wax

82. CONCLUSION 2

83. “Preservation of abutment teeth and
supporting structures of the oral cavity
depends on accurate and knowledgeable
survey and design.
The use of a dental surveyor is critical for
planning the modifications of all tooth
surfaces that will be involved with the
support, stabilization, and retention of the
prosthesis.
83