Principles of Surveying Flashcards
what is the name of the surveyor we use at UMKC
Ney Jelenko
what are the dental surveyor tools
-analyzing rod
- carbon marker
- carbon sheath
- undercut gauges (0.010, 0.020, and 0.030.)
- wax trimmer/knife
what are the functions of the dental surveyor
- survey diagnostic cast
- contour wax patterns
- contour ceramic and cast restorations
-place attachments requiring parallelism - survey master cast
what is the objective of surveying diagnostic cast
- determine the most acceptable path of insertion
- identify proximal tooth surfaces that can function as guiding planes
- locate and measure areas of teeth that may be used for retention
- determine if soft or bony areas of interference exist
- determine most suitable path of insertion to satisfy esthetics
- delineate height of contour on abutment teeth
- record cast position to selected path of insertion
what is the survey procedure for diagnostic cast
- path of insertion determined
- mark the height of contour/survey line
- measure/mark retentive undercut
- tripod cast
what is the path of insertion determined based on
guiding planes
- retentive undercut
- interferences
- esthetics
what is the path of insertion
the direction in which the RPD is inserted and removed from the abutment teeth
what are guiding planes
parallel, flattened surfaces at proximal or axial surfaces of teeth
- contact minor connectors, guiding plates
- greater number of GPs- path of insertion more specific
- increase RPD stability and retention
what is the guiding planes identified by
tilting cast in anterior- posterior direction until maximum parallelism of proximal surfaces
- anterior posterior tilt as viewed from rear of cast table
what is the analyzing rod used to identify
potential surfaces that can be converted to guiding planes by selective grinding in occlusal 1/3 - 1/2
the final orientation of the guiding plane is seldom ______ from horizontal
greater than 10-15 degrees
what is a retentive undercut
RPD mechanical retention provided by clasp that engages retentive undercut
what is the purpose of a retentive undercut
resists RPD dislodging forces
where is the undercut area located
between survey line and gingival margin
what is the height of contour/ survey line
line encircling a tooth that designates its greatest diameter at a selected position determined by a dental surveryor
height of contour will change if _____ is changed
axial inclination
what is a suprabulge area
portion of tooth above the height of contour
what is the infrabulge area
portion of tooth below the height of contour in relation to the path of insertion
is the retentive undercut in the infrabulge area or suprabulge area
infrabulge area
what is the only thing that contacts the tooth below the survey line
retentive clasp tips
what are the areas of retentive undercut
mesiofacial, midfacial, distofacial
- mesiolingual and distolingual
where is the ideal retentive undercut located
within gingival 1/3 at least 1 mm from gingival margin
what should you manipulate to distribute undercut to abutments
mediolateral tilt of cast
what is a false undercut
- illusion of undercut due to excessive cast tilt
- will not exist clinically
- awkward path of insertion
what are the typical interference areas
- lingually inclined mandibular teeth
- buccally inclined maxillary teeth
- bony buccal exostoses and tori
- height of contour too high, clasp placement too high
- tissue undercut area of bar clasp
how do you eliminate interferences
- alter tilt of cast/ change path of insertion
- maintain cast tilt, eliminate by surgery or recontouring of teeth
how do you improve esthetics
-alter mediolateral cast tilt
- if inadequate space for natural tooth width, recontour proximal surfaces to restore lost dimension
how do you mark the height of contour/survey line
side of carbon marker indicates survey line of abutment teeth at chosen path of insertion
- tip of marker will produce incorrect survey line
what parts of the RPD are located above the survey line
all components except terminal 1/3 of clasp
where is the ideal survey line located
at the junction of middle and gingival 1/3
where is the retentive terminal 1/3 of clasp located
in gingival 1/3
where is proximal 2/3 of retentive clasp and reciprocal clasp located
in middle 1/3 above the survey line
what happens if the survey line is too hgih
- may interfere with occlusion
- increased leverage on tooth
what should you do if the survey line is too high
recontour the tooth to lower survey line
what happens if the survey line is too low
- no undercuts exist for clasp retention
- at or near gingival margin
what should you do if the survey line is too low
- cannot use enamoplasty
- requires surveyed crown
how are undercuts measured
undercut gauge at chosen path of insertion
what does the amount of undercut vary depending on
clasp type
what is the undercut for Cr-Co or Ni-Cr cast clasp
0.01”
what is the undercut for wrought wire clasp
0.02” or 0.03”
what do you do if there is an inadequate retentive undercut
- enameloplasty to create undercut
- addition of composite at site to create undercut
- surveyed crown
what does the tripod cast do
record tilt of cast at chosen path of insertion
what are the 2 methods of tripod cast and what do we use at UMKC
- adjust height of vertical arm: marker touches 3 widely separate tissue surface areas. circle each tripod mark
- draw vertical lines parallel to analyzing rod on 3 sides of the cast - UMKC method
what is the color code for RPD design at UMKC
- blue: metal framework outline, wrought iron clasp
- red: indicate retentive undercut, indicate tooth modification areas, guiding planes, survey line reposition, rest seat areas
- black: survey line, tripod marks and soft tissue undercuts
what is the order of RPD survey and design overview and what are the steps in each
-survey diagnostic cast: path of insertion, mark survey line, mark retentive undercut, tripod cast
- RPD design/ tooth modifications: draw on diagnostic cast
- mouth preparation: tooth modifications
- master cast: resurvey: guiding planes, survey line, retentive undercut, tripod. framework made
