principle of surveying

Question 1

paralleling instrument used in RPD fabrication

Answer 1

dental survey

Question 2

dental surveyor functions

Answer 2

-survey diagnostic case
-contour wax patterns
-contour ceramic and cast restorations
-place attachments requiring parallelism
-survey master cast

Question 3

what are the 7 objectives of surveying diagnostic cast

Answer 3

1. determine the most acceptable path of insertion
2. identify proximal tooth surfaces that can function as guiding planes
3. locate and measure areas of teeth that may be used for retention
4. determine if soft or bony areas of interferences (undercuts) exist
5. determine most suitable path of insertion to satisfy esthetics
6. delineate height of contour on abutment teeth
7. record cast position to selected path of insertion (tripod cast)

Question 4

diagnostic cast survey procedures:

Answer 4

1. path of insertion determined
2. mark height of contour/survey line
3. measure/mark retentive undercut
4. tripod cast

Question 5

this is based on guiding planes, retentive undercut, interferences, esthetics

Answer 5

path of insertion determined

Question 6

the direction in which the RPD is inserted and removed from the abutment teeth

Answer 6

path of insertion

Question 7

patient is unable to open mouth sufficiently to accommodate when

Answer 7

there is an exaggerated tilt to path of insertion

Question 8

path of insertion 4 factors

Answer 8

1. guiding planes
2. retentive undercuts
3. interferences
4. esthetics

Question 9

parallel, flattened surfaces at proximal or axial surfaces of teeth

Answer 9

guiding planes

Question 10

contacts minor connectors aka guiding plates

Answer 10

guiding planes

Question 11

the greater number of guiding planes, the

Answer 11

path of insertion is more specific

Question 12

guiding planes increase

Answer 12

RPD stability and retention

Question 13

the guiding planes are identified by tilting cast in

Answer 13

tilting cast in anterior-posterior direction until max parallelism of proximal surfaces

Question 14

what is used to identify potential surfaces that can be converted to guiding planes by selective grinding in occlusal 1/3 to 1/2

Answer 14

analyzing rods

Question 15

the final orientation for guiding planes is rarely > ______ degrees from horizontal

Answer 15

10-15 degrees

Question 16

RPD mechanical retention provided by ____ that engages retentive undercut

Answer 16

clasp

Question 17

this resist RPD dislodging forces

Answer 17

clasp that engages retentive undercuts

Question 18

where do undercut area lies

Answer 18

between survey line and gingival margin

Question 19

line encircling a tooth that designates its greatest diameter at a selected position determined by a dental surveyor

Answer 19

survey line

Question 20

what will be changed if the axial inclination is changed

Answer 20

survey line

Question 21

portion of tooth above height of contour

Answer 21

suprabulge area

Question 22

portion of tooth below height of contour in relation to path of insertion

Answer 22

infrabluge area

Question 23

what area is the retentive undercut within

Answer 23

infrabulge

Question 24

where is the retentive clasp tip found

Answer 24

in infrabulge
(contact tooth below survey line)

Question 25

where ideally is the retentive undercut within

Answer 25

within gingival 1/3 at least 1mm from gingival margin

Question 26

how should cast tilt to equally distribute retentive undercut to abutments

Answer 26

not vary far from horizontal

Question 27

illusion of undercut due to excessive cast tile -will not exist clinically -awkward path of insertion and pt unable to place RPD

Answer 27

false undercut

Question 28

what are the typical interference areas

Answer 28

-lingually-inclined mand teeth -buccally-inclined max teeth -bony buccal exotoses, tori -height of contour toot high, clasp would be placed too high -tissue undercut area of bar clasp

Question 29

locate and eliminate interferences such as teeth, soft tissue, and exostoses when

Answer 29

after tilt of cast/change path of insertion maintain cast tilt, eliminate by surgery or recontouring of teeth

Question 30

if there is inadequate space for natural tooth width, do what

Answer 30

recontour proximal surfaces to restore lost dimension

Question 31

this indicates survery line of abutment teeth at chosen path of insertion

Answer 31

side of carbon marker (tip of marker will produce incorrect survey line)

Question 33

where is the survey line located

Answer 33

junction of middle and gingival 1/3

Question 34

where retentive clasp located? reciprocal clasp located?

Answer 34

retentive: proximal 2/3 of retentive about survey line and tip in infrabulge or gingival 1/3 reciprocal: middle 1/3 above survey line

Question 35

if the survey line at the chosen path of insertion is too near occlusal surface, what does this mean

Answer 35

the clasp is too high on the tooth which can interfere with occlusion, increase leverage on tooth, and tooth recontoured to lower survey line

Question 36

if the survey line at chosen path of insertion is too low:

Answer 36

no undercuts exist, survey line is at/near gingival margin, cannot use enameoplasty to change, requires surveyed crown!!

Question 37

amount of undercut varies depending on clasp type:

Answer 37

0.01 for Cr-Co or Ni-Cr cast clasp 0.02 or 0.03 for wrought wire clasp

Question 38

if inadequate retentive undercut

Answer 38

1. enameoplasty to create undercut (dimple) 2. addition of composite at site to create undercut -surveyed crown

Question 39

records tilt of cast at chosen path of insertion so can reestablish path of insertion

Answer 39

tripod cast

Question 40

what are the 2 methods of tripoding casts

Answer 40

1. adjust height of vertical arm: marker touches 3 widely separate tissue surface areas in one plane then circle each tripod mark 2. UMKC method draw vertical lines parallel to analyzing rod on 3 sides of cast (lines widely separated)

Question 41

after surveying is complete what are applied to design RPD

Answer 41

mechanical and biologic principles RPD is then drawn on diagnostic cast

Question 42

color code for RPD design

Answer 42

blue: metal framework wrought wire clasp red: indicate retentive undercut indicate tooth modification areas guiding planes, survey line reposition, rest seat areas black: survey line tripod marks soft tissue undercuts

Question 43

what do you do after mouth preparations are complete

Answer 43

impressions for master cast resurvey master cast: -align guiding planes -mark retentive undercuts -mark survey line -tripod cast