surveyors in Removable partial Dentures/RPD

Dental Surveyor
• www.asiandentalacademy.org

DEFINITION
Instrument used to determine the relative
parallelism of two or more surfaces of the
teeth or other parts of the cast of a dental arch.

PURPOSES
• Modifications of oral structure that are
necessary to fabricate a RPD.
• Surveying the diagnostic cast ,
• Recon touring abutment teeth on the
diagnostic cast ,
• Contouring wax patterns
• Measuring a specific depth of under cut
• Surveying ceramic veneer crowns
• Placing intra coronal retainers
• Placing internal rests,
• Blocking out the master cast

TYPES
• Ney
• Jelenko.
• Advanced

Neys surveyor

Jelenko.

Parts of surveyor
• Platform- on which base is moved ,
• Vertical Arm-supports super structure
• Horizontal Arm- surveying tool suspends
• Base- table swivels

• Paralleling tool or Guide line marker
• Mandrel- holding special tools
• Table – cast is attached

• Ney’s
• First Surveyor
• Arm is fixed
• Vertical arm is
retained by friction
with in a fixed
bearing
• Jelenko
Arm is swivels
• Vertical arm is spring
mounted and returns to
the top position when it
is released.
• Horizontal arm made to
swivel

SURVEYING DIAGNOSTIC CAST
• Objectives-
• To determine path of placement
– Path of placement is the direction in which a restoration moves from the
point of initial contact with the supporting teeth to its terminal resting
position
• To identify proximal tooth surfaces that are need to be made
parallel, so that they act as guiding planes.
• To locate and measure areas of teeth that may be used for
retention
• To permit and accurate charting of the mouth preparation to be
made.

• To delineate the height of contour on
abutment teeth and to locate areas of
undesirable tooth under cuts that are to be
avoided’
• To record the cast position
in relation to the selected path
of placement for future
reference.

CONTOURING WAX PATTERNS
• The surveying blade is used as a wax carver during this phase
of mouth preparation so that the proposed path of placement
may be maintained throughout the preparation of cast
restoration for abutment teeth.
• Guiding planes on all proximal surfaces of the wax patterns
adjacent to edentulous areas should be made parallel to the
previously determined path of placement.
• Those surfaces of restoration that are to provide retention for
clasp arms should be contoured so that retentive clasp may be
placed in the cervical third of the crown for best esthetic
advantage.

SURVEYING CERAMIC VENEER CROWNS
• Ceramic veneer crowns are often used to
restore abutment teeth on which extra
coronal direct retainers will be placed.
• Surveyor is used to contour all areas of the
wax patterns for the veneer crown except
for the buccal or labial surface.

PLACEMENT OF INTRA CORONAL
RETAINERS
• Surveyor is used as follows:-
• To select the path of placement in relation to the long
axis of the abutment teeth that will avoid areas of
interference.
• To carve recesses in wax patterns, to place internal
attachment trays in wax patterns , to cut recesses in
castings with the hand piece holder.
• To place key way portion of the attachment in the
casting before investing and soldering .

PLACEMENT INTERNAL REST SEATS
• Surveyor may be used as a drill press with a dental hand
piece attached to the vertical arm by a hand piece holder.
• internal rest seats may be carved in the wax pattern and
further refined with the hand piece after casting , or the entire
rest seat may be cut in cast restoration with the hand piece.
• It is best to carve the outline form of rest seat in the wax and
refine the casting with the hand piece.
• Internal rest in partial denture construction provides a positive
occulusal support ,horizontal stabilization through the
parallelism of vertical walls.

MACHINING CAST RESTORATION
• With hand piece holder attached, axial surface of
cast and ceramic restoration may be refined by
machining with a suitable cylindrical
carborundrum point.
• Proximal surfaces of crowns and inlays ,which
will serve has guiding planes and vertical
surfaces above crown ledges may be improved
by machining.

SURVEYING MASTER CAST
• surveying master cast follows
• Mouth preparation, path of placement ,location
of retentive areas and location of remaining
interference must be known before proceeding
with final design of denture frame work.

Objectives-
• To select the most suitable path of placement that satisfy
the requirements of guiding planes retention
,noninterference and esthetics.
• To locate undesirable under cut areas .
• To permit measurements of retentive areas and to identify
the location of clasp terminals and flexibility of clasp arm
being used .
• To trim blackout material parallel to the path of placement
before duplication

FACTORS THAT DETERMINE PATH OF
PLACEMENT AND REMOVAL
• Guiding planes-
• Retentive areas –
• Interference-
• Esthetics-

• GUIDING PLANES-
• Proximal tooth surfaces that bear a parallel relation ship
to one another must either the found or be created to act
has guiding planes during placement and removal of
prosthesis.
• These are necessary to ensure predictable clasp assembly
function, including retention and stabilization .
• For a clasp retentive its retentive arm must be forced to
flex.
• These are necessary to give a positive direction to the
moment of the restoration. • www.asiandentalacademy.org

• RETENTIVE AREAS-
• Retentive areas must exist for a given path of
placement and must be contacted by retentive
clasp arm ,which are forced to flex over a
convex surface during placement and
removal.

• INTERFERENCE-
• The prosthesis must be designed so that it may
be placed and removed without encountering
tooth or soft tissue interference.
• It may be eliminated during mouth preparation
by surgery ,modifying interfering tooth surfaces
or altering tooth contours.

• ESTHETICS-
• Less Clasp Metal & Base Material may be
displayed.
• It also detects choice of path selected when
missing anterior teeth must be replaced with
partial denture.
• When restorations are to be made ,they should
be contoured to permit the least display of
clasp metal • www.asiandentalacademy.org

STEP BY STEP PROCEDURES
• Attach the cast to the adjustable surveyor table
by means of clamp provided .position the
adjustable table so that the occulusal surface of
the teeth are approximately parallel to the
platform.
• Such orientation is a tentative but practical
way to considering the factors that influence
the path of placement and removal.

• www.asiandentalacademy.org• www.asiandentalacademy.org

• GUIDING PLANE-
• Determine the related parallelism of proximal surfaces of the
potential abutment teeth by contacting the proximal tooth
surfaces with the surveyor blade or diagnostic stylus .alter the
cast position anteroposteriorly until these proximal surfaces are
in a close to parallel relation to one another as possible.
• For posterior modification spaces this will determine the
anteroposterior tilt of the cast in relation to the vertical arm of
the surveyor.
• Other axial surfaces of abutment teeth may also be used as
guiding planes.

• RETENTIVE AREAS –
• By contacting buccal and lingual surfaces of
abutment teeth with the surveyor blade ,the amount
of retention existing below their height of convexity
may be determined.
• Alter the cast position by tilting it laterally until
similar retentive areas exist on the principal
abutment teeth.
• If only two abutment teeth are involved ,as in
Kennedy's class1 partially edentulous arch ,they are
both principle abutments .

• If 4 abutment teeth are involved as in
Kennedy's class III modification 1 arch
,there are all principle abutments ,and
retentive areas should be located on all four.
• In tilting cast laterally to establish
reasonable uniformity of retention ,it is
necessary to rotate the table about an
imaginary longitudinal axis without
disturbing the AP tilt

• INTERFERENCEs
• If a mandibular cast being surveyed ,check lingual
surfaces that will be crossed by a lingual bar major
connector during placement and removal.
• Bony prominences are cause of interference to a lingual
bar connector.
• If interference is bilaterally, surgery or reencountering
of lingual tooth surfaces, may unavoidable.
• If it is only unilateral , a change in the lateral tilt may
prevent an area of tooth or tissue interference
• Reshaping tooth surfaces during mouth preparation can
eliminate areas of interference to proper placement of
clasp arms. • www.asiandentalacademy.org

• ESTHETICS-
• Clasp designs that will provide satisfactory esthetics
usually may be selected for any given path of
placement .in some instances r placed bar clasp arms
may be used to advantage, in others circumferential
clasp arms located cervically may be used.
• When anterior replacements ,the choice of path is
limited to a more vertical one.

FINAL PATH OF PLACEMENT
• It will be Ap and lateral position cast, in relation to vertical
arm of the surveyor that best satisfies all 4 factors… i.e……
• Guiding planes,retention,interference ,and esthetics.
• All proposed mouth changes should be indicated diagnostic
casts in red pencil.
• Tentative design should be sketched on the diagnostic cast
in pencil after deciding on the path of placement.
• Red pencil marks are used to indicate location of areas to be
modified and the location of rests

RECORDING RELATION OF CAST TO
SURVEYOR
• It is used so that it may be returned to the surveyor for future
refference,especially during mouth preparation.
• Two methods are most convenient and accurate.
• Method 1-
Place 3 widely divergent dots on tissue surface of the cast using
the tip of carbon marker ,with vertical arm of surveyor in a locked
position. dots should be encircled with color pencils with easy
identification. on returning ,cast to the surveyor, it may be tilted
until the tip of survey blade again contacts the 3 dots in the same
plane, this will produce the original position of cast and path of
placement, this is known as Tripoding cast.

• METHOD 2-
• Is to score 2 sides on the dorsal aspect of the base
of cast with a sharp instrument held against the
surveyor blade. By tilting cast until all 3 lines are
again parallel to surveyor blade original cast
position can be reestablished.
• At any time surveyor may involve certain amount
of error,0.2mm error can be anticipated in
reorienting cast with 3 reference point.

SURVEYING MASTER CAST
• The master cast must be surveyed as anew cast, but the
prepared proximal guiding plane surfaces will indicate the
correct anteroposterior tilt.
• The amount of guiding plane surface remaining after block
out should be maximum.
• Lateral tilt will be the position that provides equal retentive
areas on all principal abutments.
• Any interferences must be eliminated with block out. mouth
preparation must be planned and executed.
• The cast is tripoded.the surveyor blade may be replaced and
ht of convexity of each abutment tooth contours may be
delineated. • www.asiandentalacademy.org

MEASURING RETENTION
• The surveyor is used with the master cast for two
purposes 1) to delineate the height of contour of the
abutment teeth and to identify the location and
magnitude of retentive undercuts. 2)to trim blackout
of any remaining interference to placement and
removal.
• Undercut may be measured with an undercut
guage.the amount of undercut is measured in
hundredths of an inch, undercut of 0.001inch is
adequate for retention by cast retainers.• www.asiandentalacademy.org

• When a source of visible light is directed toward
tooth being surveyed, a triangle of light is visible.
this is bounded by the surfaces of the abutment
tooth on one side and blade of surveyor on other
side, apex being the point of contact at the ht of
convexity and the base being the gingival tissues .
• Retention will be determined by 1)the depth at
which the clasp terminal is placed 2)the flexibility
of the clasp arm.
• The final design may now be drawn on master cast
with a

BLOCKING OUT OF MASER CAST
• After establishment of path of placement and location
of under cut areas on the master cast ,any under cut
areas that will crossed by rigid parts of denture must
be eliminated by blackout.
• Blockout include those areas not involve that are
blocked out for convenience.
• Ledges on which clasp patterns are to be placed
• Relief beneath connectors to prevent tissue
impingement
• Relief to provide for attachment of denture base to
frame work.

• Hard in lay wax may be used has a blackout
material. it is easily applied and trimmed with
surveyor blade.
• Parallel blackout is necessary for areas that are
cervical to guiding plane surfaces and over all under
cut areas that will be crossed by major minor
connectors.
• Areas to be blocked out for convenience should be
done with hard base plate wax or oil base modeling
clay .
•

RELIEVING MASTER CAST
• Tissue under cuts that must be blocked out are parallel in
much the same manner as tooth under cuts .
• The difference between blackout and relief must be clearly
under stood. Ex. tissue under cuts that would offer
interference to the seating of lingual bar connector are
blocked out with blackout wax and trim parallel to the path
of placement.
• Adequate relief of soft tissues adjacent to lingual bar is
obtained by initial finishing and polishing of the frame
work.

Thank You

surveyors in Removable partial Dentures/RPD

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to surveyors in Removable partial Dentures/RPD

Similar to surveyors in Removable partial Dentures/RPD (20)

More from Anil Goud

More from Anil Goud (17)

Recently uploaded

Recently uploaded (20)

surveyors in Removable partial Dentures/RPD