Surveyor and surveying / dentistry dental implants

SURVEYORS ANDSURVEYORS AND
SURVEYING.SURVEYING.
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
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INTRODUCTIONINTRODUCTION

• 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.

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

• A dental surveyor has been designed asA dental surveyor has been designed as
an instrument used to determine thean instrument used to determine the
relative parallelism of two or morerelative parallelism of two or more
surfaces of the teeth or other parts of thesurfaces of the teeth or other parts of the
arch.arch.

• Dr.A.J.Fortunati is thought to be first personDr.A.J.Fortunati is thought to be first person
to employ a mechanical device to determineto employ a mechanical device to determine
the relative parallelism of tooth surfaces.the relative parallelism of tooth surfaces.
• Boston in 1918 he demonstrated a methodBoston in 1918 he demonstrated a method
for charting correct clasp placement byfor charting correct clasp placement by
using a parallelometer.using a parallelometer.
• First such instrument to be producedFirst such instrument to be produced
commercially was NEYS instrument.Nextcommercially was NEYS instrument.Next
came the WILLS surveyor.came the WILLS surveyor.

• Basically two types of surveying methodsBasically two types of surveying methods
are available.are available.
• Surveying by using parallelometer.Surveying by using parallelometer.
• Optical surveying by using light beams.Optical surveying by using light beams.

TERMINOLOGY:-TERMINOLOGY:-
SURVEY:-the procedure of locating and delineatingSURVEY:-the procedure of locating and delineating
the contour and position of the abutment teeth andthe contour and position of the abutment teeth and
associated structures before designing a removableassociated structures before designing a removable
partial denture.partial denture.
SURVEYING:-An analysis and comparison of theSURVEYING:-An analysis and comparison of the
prominence of intraoral contours associated with theprominence of intraoral contours associated with the
fabrication of prosthesis.fabrication of prosthesis.www.indiandentalacademy.comwww.indiandentalacademy.com

• Survey line:-a lineSurvey line:-a line
produced on a cast byproduced on a cast by
surveyor by markingsurveyor by marking
at the greatestat the greatest
prominence ofprominence of
contour in relation tocontour in relation to
the planned path ofthe planned path of
insertion.insertion.

• SURVEYOR:-A paralleling instrument usedSURVEYOR:-A paralleling instrument used
in construction prosthesis to locate andin construction prosthesis to locate and
delineate the contours and relative positionsdelineate the contours and relative positions
of abutment teeth and associated structures.of abutment teeth and associated structures.
• CLASP:-The component of clasp assemblyCLASP:-The component of clasp assembly
that engages a portion of the tooth surfacethat engages a portion of the tooth surface
and either enters an undercut for retention orand either enters an undercut for retention or
remains entirely above the height of contourremains entirely above the height of contour
to act as a reciprocatingto act as a reciprocating
element.Generally,it is used to stabilize andelement.Generally,it is used to stabilize and
retain a removable prosthesis.retain a removable prosthesis.

• Cingulum rest:- ACingulum rest:- A
portion of a castportion of a cast
partial denture thatpartial denture that
contacts on naturalcontacts on natural
cingulum of tooth.cingulum of tooth.

• Lingual rest seat:-Lingual rest seat:-
The depressedThe depressed
prepared on theprepared on the
lingual surface of anlingual surface of an
abutment to acceptabutment to accept
the metal rest ofthe metal rest of

• Incisal rest:-A rigidIncisal rest:-A rigid
extension of a partialextension of a partial
denture that contactsdenture that contacts
the incisal rest.the incisal rest.

• Occlusal rest:-A rigidOcclusal rest:-A rigid
extension of aextension of a
removable partialremovable partial
denture that contactsdenture that contacts
the occlusal surfacethe occlusal surface
of a tooth or aof a tooth or a
restoration,therestoration,the
occlusal surfaceocclusal surface
which may beenwhich may been
prepared to relieve it.prepared to relieve it.

• PARTIAL DENTURE REST:-A rigid extension of aPARTIAL DENTURE REST:-A rigid extension of a
fixed or removable partial denture that preventsfixed or removable partial denture that prevents
movement toward the mucosa and transmitsmovement toward the mucosa and transmits
functional forces to the teeth.functional forces to the teeth.
• RETAINER:-Any type of device used for stabilizationRETAINER:-Any type of device used for stabilization
or retention of a prosthesis.or retention of a prosthesis.
• DIRECT RETAINER:-That component of removableDIRECT RETAINER:-That component of removable
partial denture used to retain and preventpartial denture used to retain and prevent
dislodgement,consisting of clasp assembly ordislodgement,consisting of clasp assembly or
precision attachment.precision attachment.
• INDIRECT RETAINER:-The component of RPD thatINDIRECT RETAINER:-The component of RPD that
assists the direct retainers in preventing displacementassists the direct retainers in preventing displacement
of distal extension denture base by functioningof distal extension denture base by functioning
through lever action on the opposite side of thethrough lever action on the opposite side of the
fulcrum line when the denture base moves away fromfulcrum line when the denture base moves away from
the tissues in pure rotation around the fulcrum line.the tissues in pure rotation around the fulcrum line.

• GUIDING-PLANES:-Vertically parallel surfaces onGUIDING-PLANES:-Vertically parallel surfaces on
abutment teeth oriented so as to contribute to theabutment teeth oriented so as to contribute to the
direction of path of placement and removal ofdirection of path of placement and removal of
• INTERNAL REST:-A pre-fabricated,rigid metallicINTERNAL REST:-A pre-fabricated,rigid metallic
extension in a fixed or removable partial dentureextension in a fixed or removable partial denture
that fits intimately into the box type rest seat orthat fits intimately into the box type rest seat or
keyway portion of a precision attachment in a castkeyway portion of a precision attachment in a cast
restoration.restoration.
• INTERNAL ATTACHMENT:-An inter lockingINTERNAL ATTACHMENT:-An inter locking
device,one component of which is fixed to andevice,one component of which is fixed to an
abutment or abutments, and the other is integratedabutment or abutments, and the other is integrated
into a removable prosthesis to stabilize and/orinto a removable prosthesis to stabilize and/or
retain it.retain it.

• BLOCK-OUT:-1.Elimination of undesirable underBLOCK-OUT:-1.Elimination of undesirable under
cuts on the cast.cuts on the cast.
• 2.The process of applying wax or another similar2.The process of applying wax or another similar
temporary substance to undercut portions of casttemporary substance to undercut portions of cast
so as to leave only those undercuts essential to theso as to leave only those undercuts essential to the
planned construction of prosthesis.planned construction of prosthesis.

SIGNIFICANCE OF SURVEY LINESSIGNIFICANCE OF SURVEY LINES

• All rigid components of the partial dentureAll rigid components of the partial denture
must be kept occlusal it.must be kept occlusal it.
• Normally only the terminal third of theNormally only the terminal third of the
retentive clasp is placed gingival to the surveyretentive clasp is placed gingival to the survey
line.line.
• The survey line also helps locate areas ofThe survey line also helps locate areas of
undesirable tooth undercuts that must beundesirable 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 of diameterIt represents the greatest bulge of diameter
of a crown when viewed from a specificof a crown when viewed from a specific
angle or changes as the vertical position ofangle or changes as the vertical position of
the tooth changed.the tooth changed.
• Tipping or tilting the cast will cause theTipping or tilting the cast will cause the
height of contour to move accordingly.height of contour to move accordingly.

• DE VAN 1935 usedDE VAN 1935 used
some clarifying termssome clarifying terms
to describe retention.to describe retention.
• He referred to theHe referred to the
surface of a tooth thatsurface of a tooth that
is occlusal to theis occlusal to the
height of contour asheight of contour as
SUPRA BULGE andSUPRA BULGE and
surface incliningsurface inclining
cervically as INFRAcervically as INFRA
BULGE.BULGE.

• A survey line is a line drawn round theA survey line is a line drawn round the
greatest contour of a tooth in relation to thegreatest contour of a tooth in relation to the
common path of placement or removalcommon path of placement or removal
(DAVID M WATT)(DAVID M WATT)
• A survey line is indicated those parts of teethA survey line is indicated those parts of teeth
that can be used to used for retention ,thosethat can be used to used for retention ,those
parts of the teeth on the occlusal side of theparts of the teeth on the occlusal side of the
line can not be used.line can not be used.

BLATTERFEIN’SBLATTERFEIN’S
CLASSIFICATION OF BUCCALCLASSIFICATION OF BUCCAL
&LINGUAL SURVEY LINES.&LINGUAL SURVEY LINES.

• NEAR ZONE & FAR ZONE:-NEAR ZONE & FAR ZONE:-
• If the buccal and lingual tooth surfaces areIf the buccal and lingual tooth surfaces are
divided into two halves by vertical linedivided into two halves by vertical line
through long axis, the near zone is that halfthrough long axis, the near zone is that half
which lies nearer to the saddle and far zonewhich lies nearer to the saddle and far zone
is more remote from the saddle.is more remote from the saddle.
• DIAGONAL SURVEY LINE:-DIAGONAL SURVEY LINE:-
• Lies nearer the occlusal surface than theLies nearer the occlusal surface than the
gingival margin in the near zone of thegingival margin in the near zone of the
tooth, but opposite condition exists in the fartooth, but opposite condition exists in the far
zone.zone.
• Commonly found in buccal surfaces ofCommonly found in buccal surfaces of
canines and premolars,canines and premolars,

• MEDIUM SURVEY LINE:-MEDIUM SURVEY LINE:-
• This appears on the buccal or lingual surfaceThis appears on the buccal or lingual surface
of the tooth, approximately equidistance fromof the tooth, approximately equidistance from
the occlusal surface and gingival margin inthe occlusal surface and gingival margin in
the near zone and slightly nearer the gingivalthe near zone and slightly nearer the gingival
margin in the far zone.margin in the far zone.
• This indicates the use of occlusallyThis indicates the use of occlusally
approaching clasp.approaching clasp.www.indiandentalacademy.comwww.indiandentalacademy.com

HIGH SURVRY LINE & LOWHIGH SURVRY LINE & LOW
SURVEY LINESURVEY LINE
• High survey line:-appears much nearer to theHigh survey line:-appears much nearer to the
occlusal than gingival of the tooth in both near andocclusal than gingival of the tooth in both near and
far zone.far zone.
• It may arise as a result of abnormal tooth formIt may arise as a result of abnormal tooth form
where occlusal surface has a considerable longerwhere occlusal surface has a considerable longer
perimeter thanperimeter than
cemento-enamel junction.cemento-enamel junction.
More commonly it results from inclination of tooth.More commonly it results from inclination of tooth.
It frequently found on the buccal surfaces of theIt frequently found on the buccal surfaces of the
uppers.uppers.

• LOW SURVEY LINE:-frequently occurs as aLOW SURVEY LINE:-frequently occurs as a
result of marked inclination of the tooth,result of marked inclination of the tooth,
when it is associated with the high surveywhen it is associated with the high survey
line of the opposite side.line of the opposite side.
• A tooth surface with the low survey lineA tooth surface with the low survey line
cannot bear retentive clasp arm.cannot bear retentive clasp arm.

SURVEYING BYSURVEYING BY
PARALLALOMETERS.PARALLALOMETERS.

PARTS OF SURVEYORSPARTS OF SURVEYORS

• 1.Platform:-on which the base is moved.1.Platform:-on which the base is moved.
• 2.Vertical arm:-supports the super structure.2.Vertical arm:-supports the super structure.
• Horizontal arm:-from which the surveyingHorizontal arm:-from which the surveying
tools suspends.tools suspends.
• Table to which the cast is attached.Table to which the cast is attached.
• Base on which the table swivels.Base on which the table swivels.
• Paralleling tool or guideline marker.Paralleling tool or guideline marker.
• Mandrel for holding special tools.Mandrel for holding special tools.

• TOOLS OF SURVEYOR:-TOOLS OF SURVEYOR:-
• Analyzing rodAnalyzing rodmetal rod with parallelmetal rod with parallel
sides.Used to analyze the cast to establishsides.Used to analyze the cast to establish
the path of insertion.the path of insertion.
• 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-used to scribe the lineCARBON MARKER-used to scribe the line
on the cast.on the cast.
• Wax knifeWax knifeused in the late stages of RPDused in the late stages of RPD
construction to eliminate or block out areasconstruction to eliminate or block out areas
of undesirable undercuts with wax on theof undesirable undercuts with wax on the
cast before the frame work is made.cast before the frame work is made.

PURPOSESUSES OFPURPOSESUSES OF
SURVEYORSSURVEYORS

SURVEYING THE DIAGNOSTICSURVEYING THE DIAGNOSTIC
CASTCAST

1.To determine the most desirable path of1.To determine the most desirable path of
placement that will eliminate or minimizeplacement that will eliminate or minimize
interference to placement and removal.interference to placement and removal.
• 2.To identify proximal tooth surfaces that2.To identify proximal tooth surfaces that
are or need to be made parallel so thatare or need to be made parallel so that
they act as guiding planes duringthey act as guiding planes during
placement and removal.placement and removal.
• 3.To determine whether tooth and bony3.To determine whether tooth and bony
areas of interference will need to beareas of interference will need to be
eliminated surgically or by selecting aeliminated surgically or by selecting a
different path of placement.different path of placement.www.indiandentalacademy.comwww.indiandentalacademy.com

• 4.To locate and measure areas of the teeth4.To locate and measure areas of the teeth
that may be used for the retention.that may be used for the retention.
• 5.To determine the most suitable path of5.To determine the most suitable path of
placement that will permit locating retainersplacement that will permit locating retainers
and artificial tooth to the best estheticand artificial tooth to the best esthetic
advantage.advantage.
• 6.To permit an accurate charting of the6.To permit an accurate charting of the
mouth preparations to be made.mouth preparations to be made.

• 7.To delineate the height of contour on7.To delineate the height of contour on
abutment teeth.abutment teeth.
• 8.To record cast position in relation to the8.To record cast position in relation to the
selected path of placement for futureselected path of placement for future
reference.reference.
• 9.Contouring the wax patterns.9.Contouring the wax patterns.
• 10.Surveying the ceramic veneer crown.10.Surveying the ceramic veneer crown.

• 12.Placing internal rests.12.Placing internal rests.
• 13.Machining the the cast restorations.13.Machining the the cast restorations.
• 14.Surveying and blocking out the master14.Surveying and blocking out the master
cast.cast.

STEP BY STEP PROCEDURE.STEP BY STEP PROCEDURE.

COLOR CODING.COLOR 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 not at present a universallyThere is not at present a universally
accepted color coding system. As result, anyaccepted color coding system. As result, any
system agreed to understood by laboratorysystem agreed to understood by laboratory
and submitting dentist is consideredand submitting dentist is considered
acceptable.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
that will be prepared.that will 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

• 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 theaspect of the
occluded casts foroccluded casts for
adequate space foradequate space for
cingulum rests,cingulum rests,
indirect retainers.indirect retainers.
Use black pencil forUse black pencil for
marking.marking.

• 2.Indicate with pencil,2.Indicate with pencil,
using the followingusing the following
symbols, the type ofsymbols, the type of
tooth replacement.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 the soft tissuePlace these symbols on the soft tissue
portion of the cast, adjacent to theportion of the cast, adjacent to the
edentulous area.edentulous area.

• 3.Place the cast on the cast holder at3.Place the cast on the cast holder at
horizontal tilt. Examine the teeth to behorizontal tilt. Examine the teeth to be
clapsed for favorable retentive undercutsclapsed for favorable retentive undercuts
as well as the shape and contour of theas well as the shape and contour of the
proposed abutment teeth.proposed abutment 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 castDetermine the most favorable tilt of the cast
that will permit convent and properthat will permit convent and proper
placement of clasps,minor connectorsplacement of clasps,minor connectors
anterior teeth, and denture base areas.anterior teeth, and denture base areas.

CAST TILTING.CAST TILTING.

• Tilting is changing theTilting is changing the
position of the cast,position of the cast,
which thus changeswhich thus changes
the long axis of eachthe long axis of each
tooth on the casttooth on the cast
relative to therelative to the
horizontal plane.horizontal plane.

• Change in the tiltChange in the tilt
then changes thethen changes the
position of surveyposition of survey
line and locationline and location
and extent of theand extent of the
undercut.undercut.

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

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

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

• Tilting can alsoTilting can also
used to distributeused to distribute
availableavailable
undercuts toundercuts to
produce moreproduce more
uniform retentionuniform retention
through out thethrough out the
availableavailable
abutment.abutment.

BASIC CAST TILTS.BASIC 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 at or nearof the teeth at or near
parallel to theparallel 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,theIn the posterior tilt,the
portion of the castportion of the cast
tilted downwards.tilted downwards.

• 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 tiltIn the left lateral tilt
the left portion of thethe left portion of the
cast tilted downwards.cast 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.

DETEERMINATION OF PATH OFDETEERMINATION OF PATH OF
INSERTIONINSERTION

• The tilt of the cast on the surveyor is contemplatedThe tilt of the cast on the surveyor is contemplated
to determine at what angle the partial denture willto determine at what angle the partial denture will
seat over the remaining teeth and any otherseat over the remaining teeth and any other
obstructions that may present.obstructions that may present.
• This angle that the prosthesis takes as it goes toThis angle that the prosthesis takes as it goes to
place is referred to as the PATH OF INSERTION.place is referred to as the PATH OF INSERTION.
• Any exaggerated tilt may be avoided because aAny exaggerated tilt may be avoided because a
patient would be unable to open the mouthpatient would be unable to open the mouth
sufficiently to accommodate this tilt.sufficiently to accommodate this tilt.

• Numerous factors inhibiting or influencing theNumerous factors inhibiting or influencing the
seating of restoration are considered.seating of restoration are considered.
• The path of insertion will always be parallel to theThe path of insertion will always be parallel to the
vertical arm of the surveyor and determined by thevertical arm of the surveyor and determined by the
tilt of the cast on the surveying table.tilt of the cast on the surveying table.
• The path of insertion is referred to most often as if itThe path of insertion is referred to most often as if it
were a single entity.were a single entity.
• Most influential factor as to whether a partialMost influential factor as to whether a partial
denture will have one or most paths of insertion isdenture will have one or most paths of insertion is
whether edentulous space is tooth bounded orwhether edentulous space is tooth bounded or
distal extension typedistal extension typewww.indiandentalacademy.comwww.indiandentalacademy.com

• If the edentulous space is tooth bounded itIf the edentulous space is tooth bounded it
will have only one path of insertion.will have only one path of insertion.
• If the edentulous space is distal extensionIf the edentulous space is distal extension
bases on both sided the path of insertion arebases on both sided the path of insertion are
multiple.multiple.
• If it is both tooth bounded and tissueIf it is both tooth bounded and tissue
bounded the path of insertion is determinedbounded the path of insertion is determined
by modification space.by modification space.
• The component of the denture that governsThe component of the denture that governs
the path of insertion is the minor connectorthe path of insertion is the minor connectorwww.indiandentalacademy.comwww.indiandentalacademy.com

• The minor connector is normally the onlyThe minor connector is normally the only
portion of the prosthesis that contacts theportion of the prosthesis that contacts the
guiding planes on the teeth;it should be inguiding planes on the teeth;it should be in
continual contact with the guiding planescontinual contact with the guiding planes
through out process of seating and removingthrough out process of seating and removing
the partial denture.the partial denture.
• The body and the shoulders of the clasp mayThe body and the shoulders of the clasp may
exert some influence on the path of insertionexert some influence on the path of insertion

• Path of insertion isPath of insertion is
straight downwards.straight downwards.

upward andupward and
backwards.backwards.

upward and forward.upward and forward.

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

• The following four factors must be consideredThe following four factors must be considered
before path of insertion is selected:before 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.www.indiandentalacademy.comwww.indiandentalacademy.com

• RETENTIVE UNDERCUTS:RETENTIVE UNDERCUTS:
• The first unchangeable rule to rememberThe first unchangeable rule to remember
when surveying diagnostic cast forwhen surveying diagnostic cast for
removable partial denture is that retentiveremovable partial denture is that retentive
undercuts must be present on abutmentundercuts must be present on abutment
teeth at horizontal tilt.teeth at horizontal tilt.
• The surveying procedure is always startedThe surveying procedure is always started
with the cast to be analyzed positioned in thewith the cast to be analyzed positioned in the
cast holder so that the occlusal surfaces ofcast holder so that the occlusal surfaces of
the remaining teeth are parallel to thethe remaining teeth are parallel to the
surveying table or base of the surveyor.surveying table or base of the surveyor.www.indiandentalacademy.comwww.indiandentalacademy.com

• With the analyzing rod attached to the verticalWith the analyzing rod attached to the vertical
arm,each abutment tooth is examined for thearm,each abutment tooth is examined for the
presence of retentive undercuts.presence of retentive undercuts.
• The occlusal surfaces of the teeth must be viewedThe occlusal surfaces of the teeth must be viewed
first in the horizontal plane because dislodgingfirst in the horizontal plane because dislodging
forces applied to the partial denture are alwaysforces applied to the partial denture are always
perpendicular to the occlusal plane.perpendicular to the occlusal plane.
• Resistance to this dislodging force must be presentResistance to this dislodging force must be present
when the cast is at a horizontal position.when the cast is at a horizontal position.

• If retentive undercuts are not present theyIf retentive undercuts are not present they
must be created.The obvious method is bymust be created.The obvious method is by
the use of full crown usually a full crown orthe use of full crown usually a full crown or
porcelain bonded to metal.porcelain bonded to metal.
• If either of these these types of crowns areIf either of these these types of crowns are
planned, it must be placed on the surveyorplanned, it must be placed on the surveyor
as it is being formed and contoured to satisfyas it is being formed and contoured to satisfy
the requirement of partial denture.the requirement of partial denture.
• Enamel surfaces contoured in limitedEnamel surfaces contoured in limited
circumstances to provide or improvecircumstances to provide or improve
retentive undercuts.retentive undercuts.

• Ideally proposed abutment teeth shouldIdeally proposed abutment teeth should
have 0.010 inch undercut at the mosthave 0.010 inch undercut at the most
desirable location,either the distobuccal ordesirable location,either the distobuccal or
mesiobuccal line angle and in the gingivalmesiobuccal line angle and in the gingival
third of clinical crown of the tooth.third of clinical crown of the tooth.
• Once retentive undercuts have been foundOnce retentive undercuts have been found
at the horizontal tilt,the tilt may be changedat the horizontal tilt,the tilt may be changed
to alter the amount of undercut on any givento alter the amount of undercut on any given
tooth.tooth.
• It must be remembered changing the tilt toIt must be remembered changing the tilt to
alter the amount of undercut on one toothalter the amount of undercut on one tooth
will affect the undercuts on the remainingwill affect the undercuts on the remaining
teeth.teeth.

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

INTERFERENCESINTERFERENCES

• INTERFERENCES IN MANDIBLE:INTERFERENCES IN MANDIBLE:
• Tissues lingual to the remaining teeth that will beTissues lingual to the remaining teeth that will be
crossed by the major connector during insertion.crossed by the major connector during insertion.
• One of the greatest errors in planning is attemptingOne of the greatest errors in planning is attempting
to position the major connector to avoid a lingualto position the major connector to avoid a lingual
torus especially if a lingual bar is planned as thetorus especially if a lingual bar is planned as the
major connector.major connector.
• Relief or nonrigid connector is the alternativeRelief or nonrigid connector is the alternative
planning for the framework.But the thickness of theplanning for the framework.But the thickness of the
bar is compromised and damage to the remainingbar is compromised and damage to the remaining
teeth if nonrigid connector is used.teeth if nonrigid connector is used.

• 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 planOne answer to this problem would be to plan
a labial bar major connector in place of linguala labial 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 thethe lingual surfaces or placing the
restorations.restorations. www.indiandentalacademy.comwww.indiandentalacademy.com

• INTERFERENCES IN THE MAXILLA:INTERFERENCES IN THE MAXILLA:
• One of the major sources of interferences inOne of the major sources of interferences in
maxilla is torus palatinus.maxilla is torus palatinus.
• Torus interferences with the placement ofTorus interferences with the placement of
major connector.major connector.
• Usually the design of major must be changedUsually the design of major must be changed
to avoid the torus;if not possible surgicalto avoid the torus;if not possible surgical
intervention must be accomplished.intervention must be accomplished.

• Bony exostoses or undercuts buccal to theBony exostoses or undercuts buccal to the
posterior edentulous ridge are encounteredposterior edentulous ridge are encountered
frequently.frequently.
• Surgical procedures are followed for thoseSurgical procedures are followed for those

• Buccally or facially tipped teeth are alsoBuccally or facially tipped teeth are also
source of interferences.source of interferences.
• If these buccally tilted teeth are present onIf these buccally tilted teeth are present on
one side of the arch tilting the surveyingone side of the arch tilting the surveying
table away from the teeth may lower thetable away from the teeth may lower the
height of contour sufficiently to permit theheight of contour sufficiently to permit the
clasp to be located in a nearly ideal position.clasp to be located in a nearly ideal position.
• If these inclined teeth are present both sidesIf these inclined teeth are present both sides
of arch,changing the tilt of the cast will haveof arch,changing the tilt of the cast will have
no helpful effect.no helpful effect.
• If the tipping is not severe,contour theIf the tipping is not severe,contour the
enamel surface or full crown restoration isenamel surface or full crown restoration is
given in case of severe tipping.given in case of severe tipping.

ESTHETICSESTHETICS

• To obtain optimum esthetics,To obtain optimum esthetics,
• The metal,usually in the form of clasp arms,The metal,usually in the form of clasp arms,
must be concealed as as possible withoutmust be concealed as as possible without
compromising necessary support andcompromising necessary support and
stability of the prosthesis.stability of the prosthesis.
• The artificial teeth must be placed in theThe artificial teeth must be placed in the
most natural position possible.most natural position possible.

• Avoiding unnecessary display of theAvoiding unnecessary display of the
metal,the tilt of the survey table should bemetal,the tilt of the survey table should be
such that the survey line on teeth that aresuch that the survey line on teeth that are
visible be as close to the gingival margin.visible be as close to the gingival margin.
• The ideal position of the clasp for theThe ideal position of the clasp for the
retentive purpose is gingival third of theretentive purpose is gingival third of the
tooth.tooth. www.indiandentalacademy.comwww.indiandentalacademy.com

• When lost anterior teeth are not replacedWhen lost anterior teeth are not replaced
immediately, the space remaining isimmediately, the space remaining is
frequently less than the space occupied byfrequently less than the space occupied by
the missing because of mesial drifting ofthe missing because of mesial drifting of
remaining teeth.remaining teeth.
• To counter this esthetic shortcoming,the useTo counter this esthetic shortcoming,the use
of dental surveyor is necessary.of 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 bespace of missing anterior teeth must be
given high prioritygiven high 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 reduceamount of recontouring that will be needed reduce
these undesirable undercuts and to reestablish thethese undesirable undercuts and to reestablish the
space required for optimum results.space required for optimum results.

GUIDING PLANESGUIDING PLANES

• Guiding planes are formed from the proximalGuiding planes are formed from the proximal
tooth surfaces of the teeth and aretooth surfaces of the teeth and are
contacted by the minor connectors or othercontacted by the minor connectors or other
rigid components of the partial denture.rigid components of the partial denture.
• These planes guide the prosthesis forThese planes guide the prosthesis for
removal and placement.removal and placement.
• When denture is completely seated in theWhen denture is completely seated in the
mouth, the guide planes are in intimatemouth, the guide planes are in intimate
contact with the minor connectors,help tocontact with the minor connectors,help to
stabilize against the lateral forces.stabilize against the lateral forces.

• They also help to protect the weakened teethThey also help to protect the weakened teeth
from destructive forces.from destructive forces.
• The surveyor is used to locate the potentialThe surveyor is used to locate the potential
surfaces of the teeth that can be convertedsurfaces of the teeth that can be converted
to guiding guiding planes by selectiveto guiding guiding planes by selective
grinding.grinding.
• If the teeth for which guiding planes areIf the teeth for which guiding planes are
planned are receive cast restoration, the waxplanned are receive cast restoration, the wax
patterns should be shaped by the surveyorpatterns should be shaped by the surveyor
with their surfaces parallel to the path ofwith their surfaces parallel to the path of
insertion.insertion. www.indiandentalacademy.comwww.indiandentalacademy.com

• Once tilt has been selected for givenOnce tilt has been selected for given
removable partial denture design, this tiltremovable partial denture design, this tilt
should be preserved, so that it can beshould be preserved, so that it can be
reestablished accurately to the surveyingreestablished accurately to the surveying
table.this procedure is termedtable.this procedure is termed
TRIPOIDING.TRIPOIDING.

• RECORDING THE RELATION OF CASTRECORDING THE RELATION OF CAST
TO SURVEYOR.TO SURVEYOR.
• This helps in returning the cast to theThis helps in returning the cast to the
surveyor for future reference.surveyor for future reference.
• The need for returning is any wax patterns,The need for returning is any wax patterns,
trimming, block out on master cast ortrimming, block out on master cast or
locating clasp arms in under cut areas.locating clasp arms in under cut areas.

• FOLLOWING METHODS ARE USED:-FOLLOWING METHODS ARE USED:-
• 1.One method to place 3 widely divergent1.One method to place 3 widely divergent
dots on the tissue surface of the cast with thedots on the tissue surface of the cast with the
tip of the carbon marker, having the verticaltip of the carbon marker, having the vertical
of the surveyor in a locked position.of the surveyor in a locked position.
• Preferably these dots should not be placedPreferably these dots should not be placed
on the areas of the cast involved in frameon the areas of the cast involved in frame
work designing.work designing.
• Then the dots should be encircled with aThen the dots should be encircled with a
colored pencil for easy identification.colored pencil for easy identification.

• On returning the cast the cast to theOn returning the cast the cast to the
surveyor, it may be tilted until the tip of thesurveyor, it may be tilted until the tip of the
surveyor blade on diagnostic stylus againsurveyor blade on diagnostic stylus again
contacts the 3 dots in the same place.contacts the 3 dots in the same place.
• This method is tripoiding.This method is tripoiding.

• Second method is to score two sides andSecond method is to score two sides and
dorsal aspect of the base of the cast with adorsal aspect of the base of the cast with a
sharp instrument held against the surveyorsharp instrument held against the surveyor
blade.blade.
• By tilting the cast until all three lines areBy tilting the cast until all three lines are
again parallel to the surveyor blade, theagain parallel to the surveyor blade, the
original position can be reestablished.original position can be reestablished.
• Fortunately the scratch lines will beFortunately the scratch lines will be
reproduced in duplication, there byreproduced in duplication, there by
permitting any duplicate cast to be related topermitting any duplicate cast to be related to
the surveyor in a similar manner,the surveyor in a similar manner,

• The third method of locating cast is usingThe third method of locating cast is using
thin retentive pins.thin retentive pins.
• The pins are placed in the desirable placeThe pins are placed in the desirable place
to re-orient the cast in the surveyor.to re-orient the cast in the surveyor.

• 5.Place the carbon5.Place 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 thebe contacted the

• 6.With red pencil6.With red pencil
draw in the extent ofdraw in the extent of
rest areas to berest areas to be
prepared in the mouthprepared in the mouth

• 7.Out line the exact7.Out line the exact
positioning of thepositioning of the
denture base area.denture base area.
Blue pencil indicatesBlue pencil indicates
acrylic base; Brownacrylic base; Brown
pencil indicates metalpencil indicates metal
denture basedenture base

• 8.With brown pencil8.With brown pencil
outline the frame workoutline the frame work
design to harmonizedesign to harmonize
and join the majorand join the major
connector, rest seats,connector, rest seats,
indirect retainers andindirect retainers and
minor connectors.minor connectors.

• 9.Replace the carbon9.Replace the carbon
marker withmarker with
appropriate under cutappropriate under cut
gaugegauge

• 10.With the brown10.With the brown
pencil draw the clasppencil draw the clasp
arm to the actualarm to the actual
shape, size, andshape, size, and
location desired.location desired.

• 11.Completed11.Completed
designed casts.designed casts.

SURVEYING THE MASTER CASTSURVEYING THE MASTER CAST

• The master cast for a removable partialThe master cast for a removable partial
denture is made following the completion ofdenture is made following the completion of
mouth preparation that was indicated frommouth preparation that was indicated from
design drawn on the diagnostic cast.design drawn on the diagnostic cast.
• Mouth preparation may have included theMouth preparation may have included the
placement of crowns or other restorations onplacement of crowns or other restorations on
abutment teeth,the development of theabutment teeth,the development of the
guiding planes,contouring the wax enamelguiding planes,contouring the wax enamel
surfaces, and the placement of the rest seatsurfaces, and the placement of the rest seat
preparations.preparations.

• Before the master cast is sent to theBefore the master cast is sent to the
laboratory for construction of removablelaboratory for construction of removable
partial denture frame work, it must bepartial denture frame work, it must be
surveyed to determine whether he mouthsurveyed to determine whether he mouth
preparation accomplished all it as supposedpreparation accomplished all it as supposed
to.to.
• With the master cast mounted on theWith the master cast mounted on the
surveying table at the same tilt at which thesurveying table at the same tilt at which the
diagnostic cast was designed.diagnostic cast was designed.
• In the event the mouth preparation did notIn the event the mouth preparation did not
produce the desired results,either mouthproduce the desired results,either mouth
preparation reaccomplished newpreparation reaccomplished new
impressions has to made.impressions has to made.

CONTOURING THE WAXCONTOURING THE WAX
PATTRENSPATTRENS

• The surveyor blade is used as a wax carverThe surveyor blade is used as a wax carver
during this phase.during this phase.
• The proposed path of placement may beThe proposed path of placement may be
maintained throughout the preparation of castmaintained throughout the preparation of cast
restorations for abutment teeth.restorations for abutment teeth.
• Guiding planes on all proximal surfaces ofGuiding planes on all proximal surfaces of
wax patterns adjacent to the edentulouswax patterns adjacent to the edentulous
areas should be made parallel.areas should be made parallel.
• The surfaces of restoration on whichThe surfaces of restoration on which
reciprocal and stabilizing components will bereciprocal and stabilizing components will be
placed should be contoured to permit theirplaced should be contoured to permit their
location well below occlusal surfaces and onlocation well below occlusal surfaces and on
non retentive areas.non retentive areas.

• Those surfaces of restorations that are toThose surfaces of restorations that are to
provide retention for the clasp arms shouldprovide retention for the clasp arms should
be contoured so that retentive clasps may bebe contoured so that retentive clasps may be
placed in the cervical third of the crown andplaced in the cervical third of the crown and
to the best esthetic advantage.to the best esthetic advantage.
• Generally a small amount of undercut 0.02Generally a small amount of undercut 0.02
inch or less is sufficient for retentiveinch or less is sufficient for retentive
purposes.purposes. www.indiandentalacademy.comwww.indiandentalacademy.com

CONTOURING CROWNS AND CASTCONTOURING CROWNS AND CAST
RESTORATIONSRESTORATIONS

• The working cast with restorations place inThe working cast with restorations place in
the dies placed on the surveying table.the dies 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 guiding planesselected path of insertion and guiding planes
can be refined by moving surveying table socan be refined by moving surveying table so
that the mounted stone contacts the guidingthat the mounted stone contacts the guiding
plane of the crown restoration.plane of the crown restoration.
• A final check also made with analyzing rodA final check also made with analyzing rod
to determine the height of contour andto determine the height of contour and
retentive undercuts remain as plannedretentive undercuts remain as planned

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 flours,can be created by usingwalls and flat flours,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.

• With appropriate burs in the hand piece,theWith appropriate burs in the hand piece,the
internal rests can be machined in the waxinternal rests can be machined in the wax
patterns for crowns on the abutment teeth.patterns for crowns on the abutment teeth.
• After the crowns are cast same hand pieceAfter the crowns are cast same hand piece
and burs are used to refine the rests.and burs are used to refine the rests.

IMPORTANT COSIDERATIONSIMPORTANT COSIDERATIONS
IN USE OF DENTAL SURVEYORIN USE OF DENTAL SURVEYOR

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

OPTICAL SURVEYINGOPTICAL SURVEYING

• SURVEYING WITH LIGHT BEAMS:-SURVEYING WITH LIGHT BEAMS:-
• Parallel light beams are produced by lightParallel light beams are produced by light
bulbs with small,dense filaments andbulbs with small,dense filaments and
condenser lenses contained in a box.condenser lenses contained in a box.
• The light beams are made parallel withThe light beams are made parallel with
vertical rod of conventional surveyor byvertical rod of conventional surveyor by
fixing the box firmly to an iron bar.fixing the box firmly to an iron bar.

• The cast is placed on the movable table andThe cast is placed on the movable table and
surveyed in a dark room using parallel lightsurveyed in a dark room using parallel light
beams.beams.
• The survey line is the border of light brightThe survey line is the border of light bright
and dark zones-the line where the lightand dark zones-the line where the light
beams are tangent to the cast and create abeams are tangent to the cast and create a
shadow.shadow.
• The geometric location of a conventionalThe geometric location of a conventional
lead marked survey line and the one createdlead marked survey line and the one created
by the light beams are in same location.by the light beams are in same location.www.indiandentalacademy.comwww.indiandentalacademy.com

• By tilting the table to establish various pathsBy tilting the table to establish various paths
of insertion,undercuts and survey lines mayof insertion,undercuts and survey lines may
be inspected without drawing on the cast.be inspected without drawing on the cast.
• After securing the most favorable path ofAfter securing the most favorable path of
insertion for design of removable partialinsertion for design of removable partial
denture,the table of surveyor is fixed indenture,the table of surveyor is fixed in
position and survey lines are marked withposition and survey lines are marked with
lead marker.lead marker. www.indiandentalacademy.comwww.indiandentalacademy.com

• ADVANTAGES OF SURVEYING WITHADVANTAGES OF SURVEYING WITH
LIGHT BEAMS:-LIGHT BEAMS:-
• One reason preferring optical surveying isOne reason preferring optical surveying is
that changes of survey lines and undercutsthat changes of survey lines and undercuts
can be easily inspected for different positionscan be easily inspected for different positions
of the cast.of the cast.
• In addition slight undercuts are may not beIn addition slight undercuts are may not be
determined by the lead marker can bedetermined by the lead marker can be
observed with optical surveying.observed with optical surveying.
• Many light beams provide an advantage overMany light beams provide an advantage over
one lead marker.one lead marker.www.indiandentalacademy.comwww.indiandentalacademy.com

• Optical surveying requires a dark room, andOptical surveying requires a dark room, and
light beams reflecting from cast can createlight beams reflecting from cast can create
problem in illumination.problem in illumination.
• Using colored artificial stone for the casts orUsing colored artificial stone for the casts or
covering reflecting areas with black papercovering reflecting areas with black paper
may remedy undesirable refection.may remedy undesirable refection.

RECENT ADVACES IN THERECENT ADVACES IN THE
SURVEYORS.SURVEYORS.

SUMMARY.SUMMARY.

• Proper placement and contour of theProper placement and contour of the
components of design can be achieved onlycomponents of design can be achieved only
through an adequate survey and wellthrough an adequate survey and well
planned mouth preparation.planned mouth preparation.
• The components of RPD must be selectedThe components of RPD must be selected
to control stress to the abutment teeth andto control stress to the abutment teeth and
tissues caused forces of occlusion andtissues caused forces of occlusion and
movements of distal extension bases.movements of distal extension bases.
• Alterations in design may be dictated by theAlterations in design may be dictated by the
dentists prudent judgment.dentists prudent judgment.
• Compromising the ideal in the location andCompromising the ideal in the location and
design of components,however, maydesign of components,however, may
jeopardize the potential success of thejeopardize the potential success of the
prosthesis.prosthesis. www.indiandentalacademy.comwww.indiandentalacademy.com

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