Surveyors & surveying in prosthodontics / dentistry dental implants

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INDIAN DENTAL ACADEMY
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SURVEYORS & SURVEYINGSURVEYORS & SURVEYING

ContentsContents
• IntroductionIntroduction
• History & developmentHistory & development
• TerminologyTerminology
• Types of surveyorTypes of surveyor
• Uses of surveyorUses of surveyor
• Principles in surveyingPrinciples in surveying
• Significance of survey linesSignificance of survey lines
• Parts of surveyorParts of surveyor
• Surveying the diagnostic castSurveying the diagnostic cast
• Surveying the master castSurveying the master cast
• Recent advancesRecent advances
• ConclusionConclusion
• BibliographyBibliography

INTRODUCTIONINTRODUCTION

• A partial denture will not succeed unless it isA partial denture will not succeed unless it is
designed and constructed in harmony with alldesigned and constructed in harmony with all
the physiologic and mechanical problemsthe physiologic and mechanical problems
present in the patient’s mouth.present in the patient’s mouth.
• Haphazard construction, lack of plan, lack ofHaphazard construction, lack of plan, lack of
abutment preparation is a few of the causes ofabutment preparation is a few of the causes of
partial denture failures.partial denture failures.

• A typical dental arch for which a partial dentureA typical dental arch for which a partial denture
is to be planned, consists of asymmetrical teeth,is to be planned, consists of asymmetrical teeth,
separated by edentulous areas and residualseparated by edentulous areas and residual
ridges of varied lengths.ridges of varied lengths.
• The long axis of the standing teeth usually lackThe long axis of the standing teeth usually lack
parallelism with each other, while the surface ofparallelism with each other, while the surface of
the crowns of the teeth is irregularly convex inthe crowns of the teeth is irregularly convex in
shape.shape.

• The surveying procedure is an integral part ofThe surveying procedure is an integral part of
planning process which helps the dentist toplanning process which helps the dentist to
determine which teeth are most desirable asdetermine which teeth are most desirable as
abutment for placing the rest seats for maximumabutment for placing the rest seats for maximum
support and distribute stresses withoutsupport and distribute stresses without
excessive clasping and tooth coverage.excessive clasping and tooth coverage.
• The procedure of surveying requires enormousThe procedure of surveying requires enormous
amount of learning, but time spent in study isamount of learning, but time spent in study is
worth, the reward of success that will follow.worth, the reward of success that will follow.

HISTORY &HISTORY &
DEVELOPEMENTDEVELOPEMENT

• Until 1950s most RPD were designed andUntil 1950s most RPD were designed and
constructed by time honored method of “eyeconstructed by time honored method of “eye
balling”.A prosthesis made on the basis ofballing”.A prosthesis made on the basis of
educated guesses.educated guesses.
• Before the invention of the dental surveyorsBefore the invention of the dental surveyors
dentists evaluate facial contours and undercuts ofdentists evaluate facial contours and undercuts of
teeth by visual survey of dental casts.teeth by visual survey of dental casts.
• This was accomplished by stabilizing the cast onThis was accomplished by stabilizing the cast on
table top with wax or impression compound aftertable top with wax or impression compound after
the path of placement has been determined.the path of placement has been determined.
• Its accuracy is totally dependent on theIts accuracy is totally dependent on the
operator’s ability to keep the pencils parallel andoperator’s ability to keep the pencils parallel and
steady.steady.
• The practitioner would pass a pencil lead overThe practitioner would pass a pencil lead over
the facial surfaces of the teeth to develop athe facial surfaces of the teeth to develop a
survey line at the greatest diameter of each tooth.survey line at the greatest diameter of each tooth.

• EARLY PARALLELING INSTRUMENTS:EARLY PARALLELING INSTRUMENTS:
•• Paralleling instruments were in use longParalleling instruments were in use long
before the development of a dentalbefore the development of a dental
surveyor.surveyor.
• Their purpose is to assure the properTheir purpose is to assure the proper
alignment of precision attachments.alignment of precision attachments.
• Dr. Herman E.S.Chayes developed theDr. Herman E.S.Chayes developed the
parallelometer. The instrument could beparallelometer. The instrument could be
used both intra orally and at the lab benchused both intra orally and at the lab bench
to ensure parallelism of precisionto ensure parallelism of precision
attachments. It could also be used toattachments. It could also be used to
identify non-parallel and undercutidentify non-parallel and undercut
surfaces of prepared teeth.surfaces of prepared teeth.

• The turning point in the partial dentureThe turning point in the partial denture
construction from guess work based on clinicalconstruction from guess work based on clinical
experience to scientifically based procedure wasexperience to scientifically based procedure was
the appearance of dental surveyors in 1918.the appearance of dental surveyors in 1918.

• Boston in 1918 demonstrated a method for charting correctBoston in 1918 demonstrated a method for charting correct
clasp placement by using a parallelometer.clasp placement by using a parallelometer.
• Dr. A. J. Fortunati is generally given credit for being the firstDr. A. J. Fortunati is generally given credit for being the first
to employ a mechanical device for determining the relativeto employ a mechanical device for determining the relative
parallelism of two or more tooth surfaces, in the year 1918.parallelism of two or more tooth surfaces, in the year 1918.
•The first commercial dental surveyorThe first commercial dental surveyor
to be offered to the profession wasto be offered to the profession was
designed 5 years later by engineersdesigned 5 years later by engineers
at the J.M.Ney company of Bloomfieldat the J.M.Ney company of Bloomfield
Lond(1923).Lond(1923).
•First such instrument to be producedFirst such instrument to be produced
commercially was NEYS surveyor.commercially was NEYS surveyor.
• Next came the WILLS surveyor.Next came the WILLS surveyor.

ORIGINAL WILLSORIGINAL WILLS
SURVEYOR(1929)SURVEYOR(1929)
ELECTRONICELECTRONIC
SURVEYOR(1958)SURVEYOR(1958)

• During the succeeding few decades, followingDuring the succeeding few decades, following
the introduction of the Ney instrument, a numberthe introduction of the Ney instrument, a number
of different surveying instruments were marketedof different surveying instruments were marketed
by various dental manufacturers. They are allby various dental manufacturers. They are all
constructed on the same basic principle of theconstructed on the same basic principle of the
parallelometer.parallelometer.
• Today, the Ney and Jelenko (wills) surveyors areToday, the Ney and Jelenko (wills) surveyors are
the most commonly used. Several other types ofthe most commonly used. Several other types of
surveyors have been designed and are in usesurveyors have been designed and are in use
today, many of these are more elaborate, costlytoday, many of these are more elaborate, costly
and possess little advantage than simple type ofand possess little advantage than simple type of
surveyors.surveyors.

TYPES OF SURVEYORSTYPES OF SURVEYORS ::
• The surveyor marketed by Ney dental international &The surveyor marketed by Ney dental international &
J.F.Jelenko and company dominated the market during 20J.F.Jelenko and company dominated the market during 20thth
century.century.
• By the mid 20By the mid 20thth
century many of the dental surveyorscentury many of the dental surveyors
had been developed. Mc call & Hugel reported that 11 dentalhad been developed. Mc call & Hugel reported that 11 dental
surveyors had been featured in scientific exhibits at the Americansurveyors had been featured in scientific exhibits at the American
Dental Association’s 1948 Annual meeting. These were:Dental Association’s 1948 Annual meeting. These were:
• 1. Ney 19231. Ney 1923
• 2. Brown Maier 19252. Brown Maier 1925
• 3. Wills – 19293. Wills – 1929
• 4. Lentz – circa 19354. Lentz – circa 1935
• 5. Linier – 19375. Linier – 1937
• 6. Ney – 19376. Ney – 1937
• 7. Franzwa - 19377. Franzwa - 1937
• 8. Ringle – Hiatt – Smith - 19448. Ringle – Hiatt – Smith - 1944
• 9. Mc key - 19449. Mc key - 1944
• 10. Hagman - 194410. Hagman - 1944
11. Roach - 1944

TERMINOLOGYTERMINOLOGY
SURVEYORSURVEYOR:-:- A paralleling instrument used inA paralleling instrument used in
construction of a dental prosthesis to locate andconstruction of a dental prosthesis to locate and
delineate the contours and relate positions ofdelineate the contours and relate positions of
abutment teeth and associated structuresabutment teeth and associated structures. GPT-8. GPT-8
SURVEYINGSURVEYING:-:-An analysis and comparison of theAn analysis and comparison of the
prominence of intra oral contours associated with theprominence of intra oral contours associated with the
fabrication of a dental prosthesis.fabrication of a dental prosthesis.

• Survey lineSurvey line:-:- A lineA line
produced on a cast by aproduced on a cast by a
surveyor marking thesurveyor marking the
greatest prominence ofgreatest prominence of
contour in relation to thecontour in relation to the
planned path ofplanned path of
placement of aplacement of a
restoration.restoration.

Ney surveyorNey surveyor
• It is the most widely used Surveyor.It is the most widely used Surveyor.
• In the Ney surveyor the vertical armIn the Ney surveyor the vertical arm
is retained by friction with in a fixedis retained by friction with in a fixed
bearing.bearing.
• The shaft may be moved up andThe shaft may be moved up and
down with in this bearing, butdown with in this bearing, but
remains in any vertical position untilremains in any vertical position until
again moved.again moved.

• This instrument can be converted into a milling machineThis instrument can be converted into a milling machine
by clamping a straight hand piece to the surveying arm.by clamping a straight hand piece to the surveying arm.
• Ney offers two types of clamps for this purpose.Ney offers two types of clamps for this purpose.
Replacing the instrument storage compartment on theReplacing the instrument storage compartment on the
top of the vertical arm with a ball bearing modified thetop of the vertical arm with a ball bearing modified the
Ney surveyor, allowing the horizontal arm to rotate 360Ney surveyor, allowing the horizontal arm to rotate 360
degree horizontally. This mid-1960’s modificationdegree horizontally. This mid-1960’s modification
facilitated surveying and milling.facilitated surveying and milling.

J .F. Jelenko/wills surveyorJ .F. Jelenko/wills surveyor
• Originally developed by Noble G.Originally developed by Noble G.
Wills, also known as Wills surveyorWills, also known as Wills surveyor
(circa 1937) & marketed by the(circa 1937) & marketed by the
J.F.Jelenko and company.J.F.Jelenko and company.
• Many operators preferred thisMany operators preferred this
instrument because of the springinstrument because of the spring
loaded surveying arm.loaded surveying arm.

They differ principally in that the Jelenko arm swivels whereThey differ principally in that the Jelenko arm swivels where
as the Ney arm is fixed.as the Ney arm is fixed.
•The objective of this feature is to permit movement of the armThe objective of this feature is to permit movement of the arm
in a horizontal plane rather than to depend entirely on thein a horizontal plane rather than to depend entirely on the
horizontal movement of the cast.horizontal movement of the cast.
• The vertical arm of the Jelenko surveyor is spring mountedThe vertical arm of the Jelenko surveyor is spring mounted
and returns to the top position when released.and returns to the top position when released.
• Most recent design of Jelenko surveyor still retained theMost recent design of Jelenko surveyor still retained the
spring loaded surveying arm.spring loaded surveying arm.

• Williams surveyor features gimbal stageWilliams surveyor features gimbal stage
table which is adjustable to any desiredtable which is adjustable to any desired
anterior ,posterior, or lateral tilts.anterior ,posterior, or lateral tilts.
• Advantage of this table is, center ofAdvantage of this table is, center of
rotation always remains constant.rotation always remains constant.
• Super structure of this surveyor consistsSuper structure of this surveyor consists
of jointed arm and spring supportedof jointed arm and spring supported
survey rod.survey rod.
• This surveyor is best suited forThis surveyor is best suited for
placement of internal attachments ratherplacement of internal attachments rather
than analyzing and other purposes.than analyzing and other purposes.
Williams surveyorWilliams surveyor

RetentoscopeRetentoscope
• This is a recent addition to theThis is a recent addition to the
family of surveyors.family of surveyors.
• Rotating head supports 3 horizontalRotating head supports 3 horizontal
arms.arms.
• a.a. Conventional surveying armConventional surveying arm
• b.b. Hand piece for millingHand piece for milling
• c.c. Supports a dial-undercut gauge.Supports a dial-undercut gauge.
• Work height is attached to verticalWork height is attached to vertical
arm. Table can be raised & loweredarm. Table can be raised & lowered
during surveying.during surveying. www.indiandentalacademy.comwww.indiandentalacademy.com

• The main purpose of retentoscope is to measure andThe main purpose of retentoscope is to measure and
control the undercut planes for clasp retention.control the undercut planes for clasp retention.
• This highly scientific instrument prevents theThis highly scientific instrument prevents the
employment of excessive or inadequate under cuts andemployment of excessive or inadequate under cuts and
effects an equilibration of clasp loads.effects an equilibration of clasp loads.
• It exactly determines the degree of infra bulge undercutIt exactly determines the degree of infra bulge undercut
being used.being used.

USES OF DENTAL SURVEYORUSES OF DENTAL SURVEYOR
For surveying the diagnostic castFor surveying the diagnostic cast
• To determine the most desirable path of placement and removal forTo determine the most desirable path of placement and removal for
removable partial denture.removable partial denture.
• To identify proximal tooth surface that are need to be made parallel soTo identify proximal tooth surface that are need to be made parallel so
that they act as guiding planes during placement and removal.that they act as guiding planes during placement and removal.
• To measure and locate areas of teeth that may be used for retention.To measure and locate areas of teeth that may be used for retention.
• To determine whether tooth and bony areas of interference will needTo determine whether tooth and bony areas of interference will need
to be eliminated surgically or by selecting a different path of placement.to be eliminated surgically or by selecting a different path of placement.
• To determine the most suitable path of placement that will permitTo determine the most suitable path of placement that will permit
locating retainers and artificial teeth to the best aesthetic advantages.locating retainers and artificial teeth to the best aesthetic advantages.www.indiandentalacademy.comwww.indiandentalacademy.com

• To permit accurate mouth preparation to be made toTo permit accurate mouth preparation to be made to
eliminate dental and osseous contours.eliminate dental and osseous contours.
• To delineate the heights of contours of all the teeth and toTo delineate the heights of contours of all the teeth and to
measure retentive areas.measure retentive areas.
• To record the cast position and its relation to path ofTo record the cast position and its relation to path of
placement.placement.
• To develop axial contours of wax patterns.To develop axial contours of wax patterns.
• Surveying ceramic veneer crowns (all surfaces exceptSurveying ceramic veneer crowns (all surfaces except
buccal/labial surfaces). The final glaze is done only after thebuccal/labial surfaces). The final glaze is done only after the
crowns have been recontoured.crowns have been recontoured.

• Placement of internal rest seats.Placement of internal rest seats.
• To machine guide planes.To machine guide planes.
• Surveying the master cast.Surveying the master cast.
• To select the most suitable path of insertion.To select the most suitable path of insertion.
• To measure retentive areas.To measure retentive areas.
• To locate undesirable undercut areasTo locate undesirable undercut areas
• To block out the material parallel to path of placementTo block out the material parallel to path of placementwww.indiandentalacademy.comwww.indiandentalacademy.com

Auxiliary usesAuxiliary uses
• Hold the dental hand piece in order to parallelHold the dental hand piece in order to parallel
frictional attachments in abutment teeth.frictional attachments in abutment teeth.
• Analyze the abutment teeth prior to constructingAnalyze the abutment teeth prior to constructing
a fixed prosthesis.a fixed prosthesis.
• Determine the need for alveoloplasty for anDetermine the need for alveoloplasty for an
edentulous area of the mouth.edentulous area of the mouth.

PRINCIPLES IN SURVEYING:PRINCIPLES IN SURVEYING:
• Fundamentally, surveying a tooth consists of locatingFundamentally, surveying a tooth consists of locating
accurately the height of its maximum contour in relationaccurately the height of its maximum contour in relation
to the plane, in which the model is positioned.to the plane, in which the model is positioned.
• If a vertical plane is brought into contact with a convexIf a vertical plane is brought into contact with a convex
surface they will contact at the point of maximumsurface they will contact at the point of maximum
convexity; and if the convex surface is rotated, still inconvexity; and if the convex surface is rotated, still in
contact with the plane, an imaginary line will be traced atcontact with the plane, an imaginary line will be traced at
the greatest circumference.the greatest circumference.
• This is the survey line. The area of the tooth above thisThis is the survey line. The area of the tooth above this
line is non-undercut area and the area below is theline is non-undercut area and the area below is the
undercut area.undercut area.

SIGNIFICANCE OF SURVEY LINESSIGNIFICANCE OF SURVEY LINES

• The significance of survey line is that anyThe significance of survey line is that any
rigid, nonflexible part of the prosthesis mustrigid, nonflexible part of the prosthesis must
be designed to lie above the survey line,be designed to lie above the survey line,
and only flexible parts may be designed toand only flexible parts may be designed to
go below it.go below it.
• Normally only the terminal third of theNormally only the terminal third of the
retentive clasp is placed gingival to theretentive clasp is placed gingival to the
survey line.survey line.
• The survey line also helps to locate areasThe survey line also helps to locate areas
of undesirable tooth undercuts that must beof undesirable tooth undercuts that must be
avoided or eliminated by contouring oravoided or eliminated by contouring or
placing restoration on the teeth.placing restoration on the teeth.

HEIGHT OF CONTOURHEIGHT OF CONTOUR
• The term first used by KENNEDY.The term first used by KENNEDY.
• It represents the greatest bulge ofIt represents the greatest bulge of
diameter of a crown when vieweddiameter of a crown when viewed
from a specific angle or changes asfrom a specific angle or changes as
the vertical position of the tooththe vertical position of the tooth
changed.changed.
• Tipping or tilting the cast will causeTipping or tilting the cast will cause
the height of contour to movethe height of contour to move
accordingly.accordingly.

• DE VAN 1935 used someDE VAN 1935 used some
clarifying terms toclarifying terms to
describe retention.describe retention.
• He referred to the surfaceHe referred to the surface
of a tooth that is occlusalof a tooth that is occlusal
to the height of contour asto the height of contour as
SUPRA BULGE andSUPRA BULGE and
surface inclining cervicallysurface inclining cervically
as INFRA BULGE.as INFRA BULGE.

NEAR ZONE & FAR ZONENEAR ZONE & FAR ZONE
• If the buccal and lingual tooth surfaces are divided into twoIf the buccal and lingual tooth surfaces are divided into two
halves by vertical line through long axis, the near zone ishalves by vertical line through long axis, the near zone is
that half which lies nearer to the saddle and far zone isthat half which lies nearer to the saddle and far zone is
away from the saddle.away from the saddle.

HIGH SURVEY LINEHIGH SURVEY LINE
• ThisThis appears much nearer to theappears much nearer to the
occlusal than gingival of the tooth inocclusal than gingival of the tooth in
both near and far zone.both near and far zone.
• It passes from the occlusal third inIt passes from the occlusal third in
the near zone to the occlusal third inthe near zone to the occlusal third in
the far zone.the far zone.
• More commonly it results fromMore commonly it results from
inclination of tooth.inclination of tooth.
• It is frequently found on the buccalIt is frequently found on the buccal
surfaces of the uppers teeth.surfaces of the uppers teeth.
• In this condition the undercut will beIn this condition the undercut will be
deep and hence a wrought wiredeep and hence a wrought wire
clasp is used.clasp is used. www.indiandentalacademy.comwww.indiandentalacademy.com

MEDIUM SURVEY LINEMEDIUM SURVEY LINE
• This appears on the buccal orThis appears on the buccal or
lingual surface of the tooth,lingual surface of the tooth,
approximately equidistanceapproximately equidistance
from the occlusal surface andfrom the occlusal surface and
gingival margin.gingival margin.
• It passes from the occlusal thirdIt passes from the occlusal third
in near zone to the middle thirdin near zone to the middle third
in far zone.in far zone.
• This indicates the use ofThis indicates the use of
occlusally approaching clasp.occlusally approaching clasp.

LOW SURVEY LINELOW SURVEY LINE
• Frequently occurs as aFrequently occurs as a
result of marked inclinationresult of marked inclination
of the tooth, when it isof the tooth, when it is
associated with the highassociated with the high
survey line of the oppositesurvey line of the opposite
side.side.
• A tooth surface with the lowA tooth surface with the low
survey line cannot bearsurvey line cannot bear
retentive clasp arm.retentive clasp arm.

DIAGONAL SURVEY LINEDIAGONAL SURVEY LINE
• Lies nearer the occlusalLies nearer the occlusal
surface in near zone of thesurface in near zone of the
tooth,to the cervical third oftooth,to the cervical third of
the far zone.the far zone.
• Commonly found in buccalCommonly found in buccal
surfaces of canines andsurfaces of canines and
premolars.premolars.
• A reverse circlet clasp isA reverse circlet clasp is
used.used.

PARTS OFPARTS OF
SURVEYORSURVEYOR
• Platform:-Platform:- on which the base ison which the base is
moved.moved.
• Vertical armVertical arm :-supports the super:-supports the super
structure.structure.
• Horizontal armHorizontal arm :-from which the:-from which the
surveying tools suspends.surveying tools suspends.
• Surveying ArmSurveying Arm: it carries the: it carries the
mandrelmandrel
• Locking deviceLocking device

TOOLS OF SURVEYORTOOLS OF SURVEYOR
• Analyzing rodAnalyzing rodA solid cylindrical metalA solid cylindrical metal
rod Used to analyze the cast to establish therod Used to analyze the cast to establish the
path of insertion.it is a diagnostic surveyingpath of insertion.it is a diagnostic surveying
tool.tool.
• Undercut gaugesUndercut gaugesavailable in threeavailable in three
colors.Used to measure the undercut on thecolors.Used to measure the undercut on the
cast.cast.
silver color:-0.01 inch or 0.25mm undercut.silver color:-0.01 inch or 0.25mm undercut.
gold color-0.02 inch or 0.50 mm undercut.gold color-0.02 inch or 0.50 mm undercut.
black color-0.03inch or 0.75 mm undercut.black color-0.03inch or 0.75 mm undercut.

• Carbon marker-Carbon marker-
used to scribe the line onused to scribe the line on
the cast.the cast.
• Carbon marker shieldCarbon marker shield
• Wax knifeWax knifeused in the lateused in the late
stages of RPD construction tostages of RPD construction to
eliminate or block out areas ofeliminate or block out areas of
undesirable undercuts with waxundesirable undercuts with waxwww.indiandentalacademy.comwww.indiandentalacademy.com

SURVEYING THE DIAGNOSTICSURVEYING THE DIAGNOSTIC
CASTCAST

COLOR CODINGCOLOR CODING ..

• A color coding system for the various parts ofA color coding system for the various parts of
the removable partial denture as well as forthe removable partial denture as well as for
other items of information that should beother items of information that should be
included on the diagnostic casts helpsincluded on the diagnostic casts helps
prevent confusion on the part of a dentalprevent confusion on the part of a dental
laboratory technician or any one trying tolaboratory technician or any one trying to
understand the design being proposed.understand the design being proposed.
• There is no universally accepted color codingThere is no universally accepted color coding
system. As result, any system agreed tosystem. As result, any system agreed to
understood by laboratory and submittingunderstood by laboratory and submitting
dentist is considered acceptable.dentist is considered acceptable.

• Brown crayon pencilBrown crayon pencil out line the metallic portion.out line the metallic portion.
• Blue crayon pencilBlue crayon pencil out line the acrylic portion ofout line the acrylic portion of
the denture base.the denture base.
• Red crayon pencilRed crayon pencil to indicate areas on the teethto indicate areas on the teeth
to be prepared.to be prepared.
• Solid redSolid red rests and rest seats.rests and rest seats.
• Black pencil and carbon markerBlack pencil and carbon marker used to denoteused to denote
the survey linesthe survey lines

STEP BY STEPSTEP BY STEP
PROCEDURE.PROCEDURE.

• Examine theExamine the
occludedoccluded
diagnosticdiagnostic
casts.casts.

• Indicate the proposedIndicate the proposed
rest areas by shortrest areas by short
vertical lines on thevertical lines on the
cast below the toothcast below the tooth
with black pencil.with black pencil.

• Indicate by outliningIndicate by outlining
in red any cuspalin red any cuspal
relief that will berelief that will be
needed to provideneeded to provide
adequate occlusaladequate occlusal
clearance for restclearance for rest
spaces.spaces.

• Examine the lingualExamine the lingual
aspect of the occludedaspect of the occluded
casts for adequatecasts for adequate
space for lingual rests,space for lingual rests,
indirect retainers. Useindirect retainers. Use
black pencil forblack pencil for
marking.marking.

• Indicate with pencil, using the following symbols,Indicate with pencil, using the following symbols,
the type of tooth replacement.the type of tooth replacement.
•Tube tooth.Tube tooth. TT
•FacingFacing F.F.
•Metal ponticMetal pontic M.M.
•Rein forced acrylic ponticRein forced acrylic pontic
RAP.RAP.
•Place these symbols on thePlace these symbols on the
soft tissue portion of the cast,soft tissue portion of the cast,
adjacent to the edentulousadjacent to the edentulous
area.area.

• Place the cast on the cast holder at horizontalPlace the cast on the cast holder at horizontal
tilt. Examine the teeth to be clapsed fortilt. Examine the teeth to be clapsed for
favorable retentive undercuts as well as thefavorable retentive undercuts as well as the
shape and contour of the proposed abutmentshape and contour of the proposed abutment
teeth.teeth.
• If the shape and contour of these teethIf the shape and contour of these teeth
necessitate recontouring indicate the locationnecessitate recontouring indicate the location
and extent of proposed alteration with redand extent of proposed alteration with red
crayon pencil.crayon pencil.
• Determine the most favorable tilt of the cast thatDetermine the most favorable tilt of the cast that
will permit convenient and proper placement ofwill permit convenient and proper placement of
clasps, minor connectors anterior teeth, andclasps, minor connectors anterior teeth, and
denture base areas.denture base areas.www.indiandentalacademy.comwww.indiandentalacademy.com

CAST TILTINGCAST TILTING ..

• Tilting is simply changing the position ofTilting is simply changing the position of
the cast, which thus changes the long axisthe cast, which thus changes the long axis
of each tooth on the cast relative to theof each tooth on the cast relative to the
horizontal plane.horizontal plane.

• Change in the tilt then changes the position ofChange in the tilt then changes the position of
survey line and location and extent of thesurvey line and location and extent of the
undercut.undercut.

• Tilting is used to obtain the most favorable path ofTilting is used to obtain the most favorable path of
insertion and also used to increase the desirableinsertion and also used to increase the desirable
undercuts and decrease the undesirableundercuts and decrease the undesirable
undercuts.undercuts.

• Through tilting, it isThrough tilting, it is
possible to increasepossible to increase
the undercuts on onethe undercuts on one
side of the tooth whileside of the tooth while
decrease them ondecrease them on
other side of theother side of the
tooth.tooth.

• It is important to remember that when tilting oneIt is important to remember that when tilting one
must examine effect of tilt to establish a moremust examine effect of tilt to establish a more
desirable undercuts on other teeth involved indesirable undercuts on other teeth involved in
the design.the design.

• Tilting can also usedTilting can also used
to distribute availableto distribute available
undercuts to produceundercuts to produce
more uniformmore uniform
retention through outretention through out
the availablethe available
abutment.abutment.

BASIC CAST TILTSBASIC CAST TILTS ..

• The basic position orThe basic position or
tilt of the cast ontilt of the cast on
surveyor should besurveyor should be
the horizontal tilt.the horizontal tilt.
• In the horizontalIn the horizontal
tilt,occlusal surfacestilt,occlusal surfaces
of the teeth are at orof the teeth are at or
near parallel to thenear parallel to the
horizontal plane.horizontal plane.

• In the anterior tilt, theIn the anterior tilt, the
anterior teeth areanterior teeth are
tilted downwards.tilted downwards.

• The anterior tiltThe anterior tilt
increase the mesialincrease the mesial
undercut on teeth.undercut on teeth.

• In the posterior tilt,the occlusal plane is lower inIn the posterior tilt,the occlusal plane is lower in
posterior region.posterior region.

• The posterior tilt willThe posterior tilt will
increase the distalincrease the distal
undercuts, andundercuts, and
decrease the mesialdecrease the mesial

• In the right lateral tiltIn the right lateral tilt
right portion of theright portion of the
cast tiltedcast tilted
downwards.downwards.
• The right lateral tiltThe right lateral tilt
increase undercuts onincrease undercuts on
buccal surfaces ofbuccal surfaces of
right side.right side.
• Buccal under cuts areBuccal under cuts are
reduced on left side.reduced on left side.

• In the left lateral tilt the left portion of the castIn the left lateral tilt the left portion of the cast
tilted downwards.tilted downwards.

• Left lateral tilt willLeft lateral tilt will
increase undercuts onincrease undercuts on
buccal surface of leftbuccal surface of left
and will decreaseand will decrease
undercuts on buccalundercuts on buccal
surfaces of right.surfaces of right.

DETERMINATION OF PATH OFDETERMINATION OF PATH OF
INSERTIONINSERTION

• DEFINITIONDEFINITION :The direction in which the:The direction in which the
restoration moves from the point of initialrestoration moves from the point of initial
contact of its rigid parts with supportingcontact of its rigid parts with supporting
teeth to it’s terminal resting position.teeth to it’s terminal resting position.

• The principle thatThe principle that
governs the functiongoverns the function
of a dental surveyorof a dental surveyor
requires that therequires that the
surveying rod (stylus)surveying rod (stylus)
be at a 90 degreebe at a 90 degree
angle (perpendicular)angle (perpendicular)
to the platform of theto the platform of the
surveyor.surveyor.

• positioning the castpositioning the cast
with the occlusalwith the occlusal
plane parallel to theplane parallel to the
platform of theplatform of the
surveyor establishessurveyor establishes
a perpendiculara perpendicular
relation between therelation between the
surveying rod and thesurveying rod and the
occlusal plane, whichocclusal plane, which
would accommodatewould accommodate
a path of insertiona path of insertion
perpendicular to theperpendicular to the
occlusal plane.occlusal plane.
19.jpg

• The selection of a path perpendicular to theThe selection of a path perpendicular to the
occlusal plane is considered to be favorableocclusal plane is considered to be favorable
because, against the advice of their dentist,because, against the advice of their dentist,
many patients insert their RPD’ s with a bitingmany patients insert their RPD’ s with a biting
force and because this orientation of the castforce and because this orientation of the cast
facilitates the mouth preparation necessary tofacilitates the mouth preparation necessary to
make the prosthesis function as it is intended,make the prosthesis function as it is intended,
once it is fabricated.once it is fabricated.

• Regardless of the path ofRegardless of the path of
insertion determined forinsertion determined for
any RPD, there is alwaysany RPD, there is always
a potential path ofa potential path of
dislodgment (PPD)dislodgment (PPD)
resulting from masticatoryresulting from masticatory
function that pulls thefunction that pulls the
prosthesis in a directionprosthesis in a direction
perpendicular to theperpendicular to the
occlusal plane time whenocclusal plane time when
the patient completesthe patient completes
each chewing stroke andeach chewing stroke and
begins the next one, afterbegins the next one, after
closing his mouth, opensclosing his mouth, opens
it again in theit again in the
continuation of thecontinuation of the
masticatory cycle.masticatory cycle.
18.jpg

• Thus the path of insertion (PI) is ofThus the path of insertion (PI) is of
fundamental clinical importancefundamental clinical importance
because it predetermines thebecause it predetermines the
placement of clasp arms inplacement of clasp arms in
retentive undercuts, whichretentive undercuts, which
provides the retention and helps inprovides the retention and helps in
stabilizing the prosthesis duringstabilizing the prosthesis during
function.function.
• This clasp design will provideThis clasp design will provide
adequate retention and stabilityadequate retention and stability
because the relatively long guidebecause the relatively long guide
planes at this PI are parallel toplanes at this PI are parallel to
each other and the facialeach other and the facial
undercuts for clasp retention areundercuts for clasp retention are
approximately equal to each otherapproximately equal to each other
and are equidistant below theand are equidistant below the
survey line.survey line.

• There is a considerable undercut onThere is a considerable undercut on
the facial surface of the abutment onthe facial surface of the abutment on
the left side and total absence of anthe left side and total absence of an
undercut on the abutment on theundercut on the abutment on the
right side.right side.
A framework designed at this zeroA framework designed at this zero
inclination would not have adequateinclination would not have adequate
retention.retention.
• Inclining the cast to the right sideInclining the cast to the right side
should result in a better distributionshould result in a better distribution
of the undercut surfaces betweenof the undercut surfaces between
the two abutments, creating athe two abutments, creating a
medium undercut surface on themedium undercut surface on the
facial surface of each abutment.facial surface of each abutment.
21.jpg

24.jpg 26.jpg

• If the edentulous space is tooth bounded it will haveIf the edentulous space is tooth bounded it will have
only one path of insertion.only one path of insertion.
• If the edentulous space is distal extension bases onIf the edentulous space is distal extension bases on
both sided the path of insertion are multiple.both sided the path of insertion are multiple.
• If it is both tooth bounded and tissue bounded theIf it is both tooth bounded and tissue bounded the
path of insertion is determined by modificationpath of insertion is determined by modification
space.space.
• The component of the denture that governs theThe component of the denture that governs the
path of insertion is the minor connector that joinspath of insertion is the minor connector that joins
the clasps to the major connector.the clasps to the major connector.

• The minor connector is normally the only portion ofThe minor connector is normally the only portion of
the prosthesis that contacts the guiding planes onthe prosthesis that contacts the guiding planes on
the teeth;it should be in continual contact with thethe teeth;it should be in continual contact with the
guiding planes through out process of seating andguiding planes through out process of seating and
removing the partial denture.removing the partial denture.
• The body and the shoulders of the clasp may exertThe body and the shoulders of the clasp may exert
some influence on the path of insertionsome influence on the path of insertion

FACTORS INFLUENCING THEFACTORS INFLUENCING THE
PATH OF INSERTIONPATH OF INSERTION ..

The following four factors must be considered beforeThe following four factors must be considered before
path of insertion is selected:path of insertion is selected:
• 1.Retentive undercuts.1.Retentive undercuts.
• 2.Interferences.2.Interferences.
• 3.Esthetics.3.Esthetics.
• 4.Guiding planes.4.Guiding planes.

RETENTIVE UNDERCUTSRETENTIVE UNDERCUTS ::
• The first unchangeable rule toThe first unchangeable rule to
remember when surveyingremember when surveying
diagnostic cast for removablediagnostic cast for removable
partial denture is that retentivepartial denture is that retentive
undercuts must be present onundercuts must be present on
abutment teeth when the castabutment teeth when the cast
displays a horizontal tilt.displays a horizontal tilt.
• This is necessary becauseThis is necessary because
dislodging forces are alwaysdislodging forces are always
directed perpendicular to thedirected perpendicular to the
occlusal plane.occlusal plane.

• With the analyzing rod attached toWith the analyzing rod attached to
the vertical arm,each abutmentthe vertical arm,each abutment
tooth is examined for the presencetooth is examined for the presence
of retentive undercuts.of retentive undercuts.
• Resistance to this dislodging forceResistance to this dislodging force
must be present when the cast is atmust be present when the cast is at
a horizontal position.a horizontal position.
• The surveying procedure is always started with the cast to beThe surveying procedure is always started with the cast to be
analyzed positioned in the cast holder so that the occlusalanalyzed positioned in the cast holder so that the occlusal
surfaces of the remaining teeth are parallel to the surveyingsurfaces of the remaining teeth are parallel to the surveying
table or base of the surveyor.table or base of the surveyor.

• If retentive undercuts are not presentIf retentive undercuts are not present
they must be created.The obviousthey must be created.The obvious
method is by the use of full crown ormethod is by the use of full crown or
porcelain bonded to metal.porcelain bonded to metal.
• If either of these types of crowns areIf either of these types of crowns are
planned, it must be placed on theplanned, it must be placed on the
surveyor as it is being formed andsurveyor as it is being formed and
contoured to satisfy the requirement ofcontoured to satisfy the requirement of
partial denture.partial denture.
• Enamel surfaces are contoured inEnamel surfaces are contoured in
limited circumstances to provide orlimited circumstances to provide or
improve retentive undercuts.improve retentive undercuts.

• Ideally proposed abutment teeth should haveIdeally proposed abutment teeth should have
0.010 inch undercut at the most desirable0.010 inch undercut at the most desirable
location,either the distobuccal or mesiobuccal linelocation,either the distobuccal or mesiobuccal line
angle and in the gingival third of clinical crown ofangle and in the gingival third of clinical crown of
the tooth.the tooth.
• Once retentive undercuts have been found at theOnce retentive undercuts have been found at the
horizontal tilt,the tilt may be changed to alter thehorizontal tilt,the tilt may be changed to alter the
amount of undercut on any given tooth.amount of undercut on any given tooth.
• It must be remembered changing the tilt to alterIt must be remembered changing the tilt to alter
the amount of undercut on one tooth will affect thethe amount of undercut on one tooth will affect the
undercuts on the remaining teeth.undercuts on the remaining teeth.

• The tilt is given because the retentive and reciprocalThe tilt is given because the retentive and reciprocal
arms are placed gingival or occlusal third of thearms are placed gingival or occlusal third of the
abutment, which in turn helps in the esthetic resultabutment, which in turn helps in the esthetic result
and also helps in reducing the torquing or rotationaland also helps in reducing the torquing or rotational
forces.forces.

INTERFERENCESINTERFERENCES
INTERFERENCES IN MANDIBLEINTERFERENCES IN MANDIBLE ::
• Mandibular tori can produce significantMandibular tori can produce significant
problems in RPD Therapy,surgicalproblems in RPD Therapy,surgical
removal is needed.removal is needed.
• One of the greatest errors in planning is,One of the greatest errors in planning is,
attempting to position the majorattempting to position the major
connector to avoid a lingual torusconnector to avoid a lingual torus
especially if a lingual bar is planned asespecially if a lingual bar is planned as
the major connector.the major connector.
• Relief or nonrigid connector is theRelief or nonrigid connector is the
alternative planning for the framework.Butalternative planning for the framework.But
the thickness of the bar is compromisedthe thickness of the bar is compromised
and damage to the remaining teeth ifand damage to the remaining teeth if
nonrigid connector is used.nonrigid connector is used.www.indiandentalacademy.comwww.indiandentalacademy.com

• Another frequent problem commonly seen isAnother frequent problem commonly seen is
lingually inclined teeth.lingually inclined teeth.
• If the lingually inclined teeth are bilateral,theIf the lingually inclined teeth are bilateral,the
space available for the major connector isspace available for the major connector is
reduced.This influences the tongue space.reduced.This influences the tongue space.
• One answer to this problem would be to plan aOne answer to this problem would be to plan a
labial bar major connector in place of linguallabial bar major connector in place of lingual
bar.bar.
• The bulk of the labial bar causes anThe bulk of the labial bar causes an
comfortable and unattractive plumping of thecomfortable and unattractive plumping of the
lower lip.lower lip.
• Another answer to this problem is contouringAnother answer to this problem is contouring
the lingual surfaces or placing the restorations.the lingual surfaces or placing the restorations.

INTERFERENCES IN THEINTERFERENCES IN THE
MAXILLA:MAXILLA:
• One of the major sources ofOne of the major sources of
interferences in maxilla is torusinterferences in maxilla is torus
palatinus.palatinus.
• Torus interferences with theTorus interferences with the
placement of major connector.placement of major connector.
• Usually the design of majorUsually the design of major
connector must be changed toconnector must be changed to
avoid the torus;if not possibleavoid the torus;if not possible
surgical intervention must besurgical intervention must be
accomplished.accomplished.

• Bony exostoses orBony exostoses or
undercuts buccal to theundercuts buccal to the
posterior edentulous ridgeposterior edentulous ridge
are encounteredare encountered
frequently.frequently.
• Surgical procedures areSurgical procedures are
followed for thesefollowed for these
• Buccally or facially tippedBuccally or facially tipped
teeth are also source ofteeth are also source of
interferences.interferences.

• If these buccally tilted teeth are present on one sideIf these buccally tilted teeth are present on one side
of the arch tilting the surveying table away from theof the arch tilting the surveying table away from the
teeth may lower the height of contour sufficiently toteeth may lower the height of contour sufficiently to
permit the clasp to be located in a nearly idealpermit the clasp to be located in a nearly ideal
position.position.
• If these inclined teeth are present both sides ofIf these inclined teeth are present both sides of
arch,changing the tilt of the cast will have no helpfularch,changing the tilt of the cast will have no helpful
effect. If the tipping is not severe,contour the enameleffect. If the tipping is not severe,contour the enamel
surface or full crown restoration is given in case ofsurface or full crown restoration is given in case of
severe tipping.severe tipping.

ESTHETICSESTHETICS
• To obtain optimum esthetics, the metal,usually inTo obtain optimum esthetics, the metal,usually in
the form of clasp arms must be concealed withoutthe form of clasp arms must be concealed without
compromising necessary support and stability ofcompromising necessary support and stability of
the prosthesis.the prosthesis.
• The artificial teeth must be placed in the mostThe artificial teeth must be placed in the most
natural position possible.natural position possible.

• Avoiding unnecessary display of theAvoiding unnecessary display of the
metal,the tilt of the survey tablemetal,the tilt of the survey table
should be such that the survey lineshould be such that the survey line
on teeth that are visible be as closeon teeth that are visible be as close
to the gingival margin.to the gingival margin.
• The ideal position of the clasp forThe ideal position of the clasp for
the retentive purpose is gingivalthe retentive purpose is gingival
third of the tooth.third of the tooth.
• When lost anterior teeth are notWhen lost anterior teeth are not
replaced immediately, the spacereplaced immediately, the space
remaining is frequently less than theremaining is frequently less than the
space occupied by the missingspace occupied by the missing
because of mesial drifting ofbecause of mesial drifting of
remaining teeth.remaining teeth.

• To counter this esthetic shortcoming,the use ofTo counter this esthetic shortcoming,the use of
dental surveyor is necessary.dental surveyor is necessary.
• When determining the final tilt of the cast, theWhen determining the final tilt of the cast, the
space of missing anterior teeth must be given highspace of missing anterior teeth must be given high
priority.priority.
• Tooth bounded partial denture always determinesTooth bounded partial denture always determines
the path of insertion. This means that the surveyorthe path of insertion. This means that the surveyor
must be used to determine the whether tooth has tomust be used to determine the whether tooth has to
contoured, or disking in the proximal surfaces hascontoured, or disking in the proximal surfaces has
to be done to restore the mesiodistal width of theto be done to restore the mesiodistal width of the
missing teeth.missing teeth.

• The choice is the placement of the full crownThe choice is the placement of the full crown
restorations.restorations.
• The surveyor is necessary for the determining theThe surveyor is necessary for the determining the
amount of recontouring that will be needed toamount of recontouring that will be needed to
reduce these undesirable undercuts and to re-reduce these undesirable undercuts and to re-
establish the space required for optimum results.establish the space required for optimum results.

GUIDING PLANESGUIDING PLANES
• Guiding planes are formed fromGuiding planes are formed from
the proximal tooth surfaces of thethe proximal tooth surfaces of the
teeth and are contacted by theteeth and are contacted by the
minor connectors or other rigidminor connectors or other rigid
components of the partial denture.components of the partial denture.
• These planes guide the prosthesisThese planes guide the prosthesis
for removal and placement.for removal and placement.
• When denture is completelyWhen denture is completely
seated in the mouth, the guideseated in the mouth, the guide
planes are in intimate contact withplanes are in intimate contact with
the minor connectors,help tothe minor connectors,help to
stabilize against the lateral forces.stabilize against the lateral forces.

• They also help to protect the weakened teeth fromThey also help to protect the weakened teeth from
destructive forces.destructive forces.
• The surveyor is used to locate the potentialThe surveyor is used to locate the potential
surfaces of the teeth that can be converted tosurfaces of the teeth that can be converted to
guiding planes by selective grinding.guiding planes by selective grinding.
• The teeth for which guiding planes are plannedThe teeth for which guiding planes are planned
receive cast restoration, the wax patterns should bereceive cast restoration, the wax patterns should be
shaped by the surveyor with their surfaces parallelshaped by the surveyor with their surfaces parallel
to the path of insertion.to the path of insertion.

PRESERVING TILT THROUGHPRESERVING TILT THROUGH
TRIPODINGTRIPODING
• Once tilt has been selectedOnce tilt has been selected
for given removable partialfor given removable partial
denture design, this tilt shoulddenture design, this tilt should
be preserved, so that it canbe preserved, so that it can
be reestablished accuratelybe reestablished accurately
to the surveying table.to the surveying table.
• This procedure is termedThis procedure is termed
TRIPOIDING. This helps inTRIPOIDING. This helps in
returning the cast to thereturning the cast to the
surveyor for future reference.surveyor for future reference.

Different methods to doDifferent methods to do
tripoding:-tripoding:-
METHOD 1METHOD 1
• Place 3 widely divergent dotsPlace 3 widely divergent dots
on the tissue surface of the caston the tissue surface of the cast
with the tip of the carbonwith the tip of the carbon
marker, having the vertical ofmarker, having the vertical of
the surveyor in a lockedthe surveyor in a locked
position.position.
• Preferably these dots shouldPreferably these dots should
not be placed on the areas ofnot be placed on the areas of
the cast involved in frame workthe cast involved in frame work
designing.designing. www.indiandentalacademy.comwww.indiandentalacademy.com

• On returning the cast toOn returning the cast to
the surveyor, it may bethe surveyor, it may be
tilted until the tip of thetilted until the tip of the
surveyor blade onsurveyor blade on
diagnostic stylus againdiagnostic stylus again
contacts the 3 dots in thecontacts the 3 dots in the
same place.same place.
• This method is tripoiding.This method is tripoiding.

METHOD 2METHOD 2
• Score two sides and dorsal aspect of the base ofScore two sides and dorsal aspect of the base of
the cast with a sharp instrument held against thethe cast with a sharp instrument held against the
surveyor blade.surveyor blade.
• By tilting the cast until all three lines are againBy tilting the cast until all three lines are again
parallel to the surveyor blade, the original positionparallel to the surveyor blade, the original position
can be re-established.can be re-established.
• Fortunately the scratch lines will be reproduced inFortunately the scratch lines will be reproduced in
duplication, there by permitting any duplicate castduplication, there by permitting any duplicate cast
to be related to the surveyor in a similar manner.to be related to the surveyor in a similar manner.

Method-3Method-3
• Cast position can also beCast position can also be
tripoded by marking linestripoded by marking lines
on the base of the caston the base of the cast
with the surveyor andwith the surveyor and
carbon marker after thecarbon marker after the
tilt has been selected.tilt has been selected.
• This method has an dis-This method has an dis-
advantage of smudgingadvantage of smudging
the lines during handlingthe lines during handling
of the castof the cast

• Place the carbonPlace the carbon
marker in the verticalmarker in the vertical
arm of the surveyorarm of the surveyor
and scribe the surveyand scribe the survey
line on teeth that willline on teeth that will
be contacted on thebe contacted on the
diagnostic cast.diagnostic cast.

• With red pencil drawWith red pencil draw
in the extent of restin the extent of rest
areas to be preparedareas to be prepared
in the mouthin the mouth

• If teeth requireIf teeth require
recontouring outline inrecontouring outline in
red,exact location andred,exact location and
extent of proposedextent of proposed
alterationalteration

• Out line the exactOut line the exact
positioning of the denturepositioning of the denture
base area. Blue pencilbase area. Blue pencil
indicates acrylic base;indicates acrylic base;
Brown pencil indicatesBrown pencil indicates
metal denture base.metal denture base.
• With brown pencil outlineWith brown pencil outline
the frame work design tothe frame work design to
harmonize and join theharmonize and join the
major connector, restmajor connector, rest
seats, indirect retainersseats, indirect retainers
and minor connectors.and minor connectors.

• Replace the carbonReplace the carbon
marker withmarker with
appropriate under cutappropriate under cut
gaugesgauges

• Complete designedComplete designed
casts.casts.

SURVEYING THE MASTERSURVEYING THE MASTER
CASTCAST

• The master cast for aThe master cast for a
removable partial denture isremovable partial denture is
made following the completionmade following the completion
of mouth preparation that wasof mouth preparation that was
indicated from design drawn onindicated from design drawn on
the diagnostic cast.the diagnostic cast.
• Mouth preparation may haveMouth preparation may have
included the placement ofincluded the placement of
crowns or other restorations oncrowns or other restorations on
abutment teeth,theabutment teeth,the
development of the guidingdevelopment of the guiding
planes,contouring the waxplanes,contouring the wax
enamel surfaces, and theenamel surfaces, and the
placement of the rest seatplacement of the rest seat
preparations.preparations.

• Before the master cast is sent to the laboratory forBefore the master cast is sent to the laboratory for
construction of removable partial denture frameconstruction of removable partial denture frame
work, it must be surveyed to determine whether thework, it must be surveyed to determine whether the
mouth preparation accomplished all it as supposedmouth preparation accomplished all it as supposed
to with the master cast mounted on the surveyingto with the master cast mounted on the surveying
table at the same tilt at which the diagnostic casttable at the same tilt at which the diagnostic cast
was designed.was designed.

Objectives of surveying master castObjectives of surveying master cast
• To select the most suitable path of placement by followingTo select the most suitable path of placement by following
mouth preparations that satisfy the requirements of guidemouth preparations that satisfy the requirements of guide
planes, retention, non interference and esthetics.planes, retention, non interference and esthetics.
• To permit measurements of retentive areas and to identify theTo permit measurements of retentive areas and to identify the
location of clasp terminals.location of clasp terminals.
• To locate the undesirable undercut areas that will be crossedTo locate the undesirable undercut areas that will be crossed
by rigid parts of the restoration during placement andby rigid parts of the restoration during placement and
removal,that must be eliminated by blockout.removal,that must be eliminated by blockout.
• To trim blockout material parallel to the path of placementTo trim blockout material parallel to the path of placement
before duplication.before duplication. www.indiandentalacademy.comwww.indiandentalacademy.com

. BLOCKING OUT THE MASTER
CAST
After establishment of the path of
placement and the location of undercut
areas, any undercut areas that will be
crossed by rigid parts of the denture
must be eliminated by block out. This
provides relief under frame works and
ledges on which clasp patterns are to be
placed.
Parallel block out is necessary cervical
to guiding plane surfaces and overall
undercut areas that will be crossed by
major or minor connectors. Hard base
plate wax is used for this purpose.

• Shaped blockoutShaped blockout ::
On buccal and lingualOn buccal and lingual
surfaces to locate plastic orsurfaces to locate plastic or
wax patterns for clasp arms,wax patterns for clasp arms,
hard baseplate wax is usedhard baseplate wax is used
for blockout.for blockout.

Arbitrary blockoutArbitrary blockout
• Sites-Sites-
• All gingival crevicesAll gingival crevices
• Gross tissue undercuts situated below areasGross tissue undercuts situated below areas
involved in design of dental framework.involved in design of dental framework.
• Tissue undercuts distal to cast framework.Tissue undercuts distal to cast framework.
• Labial and buccal tooth and tissue undercutsLabial and buccal tooth and tissue undercuts
not involved in denture design.not involved in denture design.

Relief areas:Relief areas:
• Sites-Sites-
• Beneath lingual bar connectors or theBeneath lingual bar connectors or the
bar portion of linguoplates.bar portion of linguoplates.
• Areas in which major connectors willAreas in which major connectors will
contact thin tissuecontact thin tissue
• usually found on lingual or mandibularusually found on lingual or mandibular
ridges and elevated palatal raphae.ridges and elevated palatal raphae.
• Hard baseplate wax is used forHard baseplate wax is used for
blockout.blockout.
• Adhesives wax is sealed to cast,shouldAdhesives wax is sealed to cast,should
be wider than major connector to bebe wider than major connector to be
placed on it.placed on it.

. DESIGN OF PROSTHESIS
When all the mouth preparation
has been completed, the definitive design
of the prosthesis is drawn on the cast and
then processed.


CONTOURING THE WAXCONTOURING THE WAX
PATTRENSPATTRENS

• The surveyor blade is used as a waxThe surveyor blade is used as a wax
carver during this phase.carver during this phase.
• The proposed path of placement may beThe proposed path of placement may be
maintained throughout the preparation ofmaintained throughout the preparation of
cast restorations for abutment teeth.cast restorations for abutment teeth.
• Guiding planes on all proximal surfacesGuiding planes on all proximal surfaces
of wax patterns adjacent to theof wax patterns adjacent to the
edentulous areas should be madeedentulous areas should be made
parallel.parallel.
• The surfaces of restoration on whichThe surfaces of restoration on which
reciprocal and stabilizing components willreciprocal and stabilizing components will
be placed should be contoured to permitbe placed should be contoured to permit
their location well below occlusal surfacestheir location well below occlusal surfaceswww.indiandentalacademy.comwww.indiandentalacademy.com

• Those surfaces ofThose surfaces of
restorations that are torestorations that are to
provide retention for theprovide retention for the
clasp arms should beclasp arms should be
contoured so that retentivecontoured so that retentive
clasps may be placed in theclasps may be placed in the
cervical third of the crowncervical third of the crown
and to the best estheticand to the best esthetic
advantage.advantage.
• Generally a small amountGenerally a small amount
of undercut 0.02 inch orof undercut 0.02 inch or
less is sufficient forless is sufficient for
retentive purposes.retentive purposes.

CONTOURING CROWNS ANDCONTOURING CROWNS AND
CAST RESTORATIONSCAST RESTORATIONS

• Surveying ceramic veneerSurveying ceramic veneer
crownscrowns::
• Ceramic veneer crowns are often used toCeramic veneer crowns are often used to
restore abutment teeth on whichrestore abutment teeth on which
extracoronal direct retainers will beextracoronal direct retainers will be
placed.placed.
• The surveyor is used to contour all areasThe surveyor is used to contour all areas
of the wax pattern except the buccal orof the wax pattern except the buccal or
labial surface.labial surface.
• Using a porcelain veneer restoration is toUsing a porcelain veneer restoration is to
develop an esthetic replica of a naturaldevelop an esthetic replica of a natural
tooth.tooth.
• Ceramic veneer portion can be fabricatedCeramic veneer portion can be fabricated
exactly to the form required for theexactly to the form required for the
planned placement of retentive claspplanned placement of retentive clasp
arms without some reshaping witharms without some reshaping with
stones.stones.

• Before the final glaze is accomplished,the abutmentBefore the final glaze is accomplished,the abutment
crowns should be returned to the surveyor on a full archcrowns should be returned to the surveyor on a full arch
cast.cast.
• Locate the areas that need recontouring.Locate the areas that need recontouring.
• The final glaze is accomplished only after the crownsThe final glaze is accomplished only after the crowns
have been recontoured.have been recontoured.

• The working cast with restorations isThe working cast with restorations is
placed on the surveying table.placed on the surveying table.
• A hand piece holder is attached to theA hand piece holder is attached to the
vertical arm of the surveyor.vertical arm of the surveyor.
• The hand piece will be parallel to theThe hand piece will be parallel to the
selected path of insertion and guidingselected path of insertion and guiding
planes can be refined by movingplanes can be refined by moving
surveying table so that the mountedsurveying table so that the mounted
stone contacts the guiding plane of thestone contacts the guiding plane of the
crown restoration.crown restoration.
• A final check also made with analyzingA final check also made with analyzing
rod to determine the height of contourrod to determine the height of contour
and retentive undercuts remain asand retentive undercuts remain as
plannedplanned www.indiandentalacademy.comwww.indiandentalacademy.com

PLACING INTERNALPLACING INTERNAL
ATTACHMENTS AND RESTSATTACHMENTS AND RESTS

• The surveyor is used to position the intra coronalThe surveyor is used to position the intra coronal
retainers or internal attachments, in the wax crownretainers or internal attachments, in the wax crown
pattern on abutment teeth as the patterns are beingpattern on abutment teeth as the patterns are being
formed.Absolute parallelism among all theformed.Absolute parallelism among all the
attachment is essential.attachment is essential.
• Internal rests,exaggerated occlusal rest with verticalInternal rests,exaggerated occlusal rest with vertical
walls and flat floors,can be created by usingwalls and flat floors,can be created by using
surveyor as a form of drill press.surveyor as a form of drill press.
• A hand piece is attached to the vertical arm of theA hand piece is attached to the vertical arm of the
surveyor by means of hand piece holder.surveyor by means of hand piece holder.

• The internal rests can beThe internal rests can be
machined in the waxmachined in the wax
patterns for crowns on thepatterns for crowns on the
abutment teeth.abutment teeth.
• After the crowns are castAfter the crowns are cast
same hand piece and burssame hand piece and burs
are used to refine the rests.are used to refine the rests.

RECENT ADVANCESRECENT ADVANCES

Electronic surveyingElectronic surveying

• A 3-dimensional computer model of a conventionalA 3-dimensional computer model of a conventional
cast from a patient is obtained using an opticalcast from a patient is obtained using an optical
surface capture device (a scanner).surface capture device (a scanner).
• The shape of number of components of aThe shape of number of components of a
removable partial denture framework was modeledremovable partial denture framework was modeled
on the 3-dimensional scan electronically, usingon the 3-dimensional scan electronically, using
computer-aided design software.computer-aided design software.
• A physical plastic shape of the components wasA physical plastic shape of the components was
produced using a Rapid Prototyping machine andproduced using a Rapid Prototyping machine and
used as a pattern.used as a pattern.

• As work progressed, a “barrel” shape was usedAs work progressed, a “barrel” shape was used
for development. The program defined thefor development. The program defined the
surface area of teeth apical to the survey line bysurface area of teeth apical to the survey line by
identifying the downward facing triangles. Theidentifying the downward facing triangles. The
upper boundary of this area defined the surveyupper boundary of this area defined the survey
line.line.
• As in physical dental cast surveying, theAs in physical dental cast surveying, the
electronic survey line is affected by theelectronic survey line is affected by the
inclination of the cast. A series of rotationalinclination of the cast. A series of rotational
transformations allowed survey lines at varioustransformations allowed survey lines at various
tilts of the cast to be identified. shows the barreltilts of the cast to be identified. shows the barrel
with a tilt of 20 degrees.with a tilt of 20 degrees.

• The effects when these programs areThe effects when these programs are
transferred to larger files of surface models of atransferred to larger files of surface models of a
scanned tooth and a cast Techniques to allowscanned tooth and a cast Techniques to allow
digital cast surveying before the production ofdigital cast surveying before the production of
patterns were also developed.patterns were also developed.
• RP [rapid prototyping] processes creates aRP [rapid prototyping] processes creates a
pattern of a removable partial denture frameworkpattern of a removable partial denture framework
in the typical dental laboratoryin the typical dental laboratory
• The results show that digital dental surveyingThe results show that digital dental surveying
and machine-produced sacrificial patterns canand machine-produced sacrificial patterns can
be accomplished.be accomplished.

Use of cad-cam technology to fabricate aUse of cad-cam technology to fabricate a
removable partial denture frameworkremovable partial denture framework
• This is the first patientThis is the first patient
fitted cobalt-chromiumfitted cobalt-chromium
RPD frameworkRPD framework
produced by cad-camproduced by cad-cam
and rapid prototypeand rapid prototype
technology.technology.

The Highriser surveyor is a pendulum arm
Blockout/Survey Instrument for fabricating removable
partial dentures.
•The arm can freely swing back and forth, rotate,
or move up or down
•Arm can be locked to hold it at a set vertical
height
•Spring tension is easily adjusted to individual
preference
•Heating element attachment is designed for easy
use and various size tips are available
•A convenient attachment holder on the column for

The SKYSCRAPER surveyor is a
dual pendulum Electronic
Blockout/Survey Instrument for
fabricating removable partial dentures.
ADVANTAGES
•The heating element does not have to
be removed when surveying;
By simply rotating the column the new
tool is ready for use

ConclusionConclusion
• When performing oral rehabilitation with removable partialWhen performing oral rehabilitation with removable partial
dentures, the objective of the dentist should be to make adentures, the objective of the dentist should be to make a
prosthesis that the patient can easily seat and remove fromprosthesis that the patient can easily seat and remove from
the mouth and yet, when seated, the prosthesis should resistthe mouth and yet, when seated, the prosthesis should resist
the dislodgment potential caused by masticatory function,the dislodgment potential caused by masticatory function,
especially mastication of sticky foods.especially mastication of sticky foods.
• The problem involves an interaction of engineering andThe problem involves an interaction of engineering and
biologic elements, so a biomechanical approach should bebiologic elements, so a biomechanical approach should be
used for its solution. On this basis, it is imperative thatused for its solution. On this basis, it is imperative that
diagnostic casts for all removable partial dentures should bediagnostic casts for all removable partial dentures should be
analyzed with a dental parallelometer (surveyor), theanalyzed with a dental parallelometer (surveyor), the
instrument that permits accurate planning of each structuralinstrument that permits accurate planning of each structural
detail of the prosthesis.detail of the prosthesis.

BIBLIOGRAPHYBIBLIOGRAPHY
• Text Book of Partial Dentures – Applegate.Text Book of Partial Dentures – Applegate.
• Text Book of Partial Dentures –Text Book of Partial Dentures –
McCracken.McCracken.
• Text Book of Partial Dentures – Osborne &Text Book of Partial Dentures – Osborne &
Lamee.Lamee.
• Text Book of Partial Dentures – Millers.Text Book of Partial Dentures – Millers.
• Text Book of Partial Dentures – A.A.Grant.Text Book of Partial Dentures – A.A.Grant.
• Clinical removable partial prosthodontics –Clinical removable partial prosthodontics –
Kenneth L. StewartKenneth L. Stewart
• Dental laboratory procedures – Rudd &Dental laboratory procedures – Rudd &
MorrowMorrow

The history and development of the dental surveyor:The history and development of the dental surveyor:
Part 1:Robert L. Engelmeir, J.P.D.2002;11;11-Part 1:Robert L. Engelmeir, J.P.D.2002;11;11-
18.18.
Part 2: “Part 2: “
J.P.D.2002;11:122-130.J.P.D.2002;11:122-130.
Part 3: “Part 3: “
J.P.D.2004;13:195-202.J.P.D.2004;13:195-202.

A technique for fabricating patterns for removableA technique for fabricating patterns for removable
partial denture frameworks using digitized castspartial denture frameworks using digitized casts
and electronic surveyingand electronic surveying
The Journal of Prosthetic DentistryThe Journal of Prosthetic Dentistry
Volume 91, Issue 1 , January 2004, Pages 85-88Volume 91, Issue 1 , January 2004, Pages 85-88
Surveying removable partial dentures: the importanceSurveying removable partial dentures: the importance
of guiding planes and path of insertion for stabilityof guiding planes and path of insertion for stability
The Journal of Prosthetic DentistryThe Journal of Prosthetic Dentistrywww.indiandentalacademy.comwww.indiandentalacademy.com

Surveyors & surveying in prosthodontics / dentistry dental implants

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