11/6: Definitive Casts

Question 1

A replica of the tooth surfaces, residual ridge areas, and/or other parts of the dental arch and/or facial structures used to fabricate a dental restoration or prosthesis

Answer 1

defintive (master or working) cast

Question 2

The positive reproduction of the form of a prepared tooth in any suitable substance

Answer 2

die

Question 3

A metal pin used in stone casts to remove die sections and replace them accurately in the original position

Answer 3

die pin

Question 4

what are the requirements for a good cast?

Answer 4

bubble and distortion free
captures both the prep and unprepped surfaces
all occlusing surfaces must allow for appropriate articulation
all soft tissues be captured

Question 5

what are the Die requirements?

Answer 5

reproduce the prepared tooth
all surfaces
uprepared tooth structure apically to finish line
adequate access for carving wax pattern margins

Question 6

what is the primary material used for dies?

Answer 6

gypsum

Question 7

what is the advantage to using gypsum?

Answer 7

compatible with all impression material
can replicate fine details
dimensional accuracy and stability
easy to use

Question 8

what is negative about gypsum?

Answer 8

abrasive can affect it

Question 9

ADA die classification

Answer 9

type 1 and 2: Impression plaster and mounting plaster
type 3: dental stone
type 4: high strength/low expansion
type 5: high strength/high expansion

Question 10

what types of gypsum are die stone?

Answer 10

type 4 and 5

Question 11

what are the desirable properties of die materials?

Answer 11

accuracy
reproduce fine detail
strength and durability
color

Question 12

what strength and durability do we want in die materials?

Answer 12

dry versus wet strength
resistance to shearing forces (edge strength)
abrasion resistance

Question 13

why is color important in die materials?

Answer 13

so CAD/CAM can scan it

Question 14

should you add powder to water or water to powder?

Answer 14

powder to water

Question 15

what is directly proportional to water?

Answer 15

setting time and fluidity

Question 16

what is inversly related to water?

Answer 16

compressive strength
setting expanion

Question 17

is a wet cast or dry cast stronger?

Answer 17

dry cast

Question 18

what should be used for surface impregnation?

Answer 18

cyanoacrylate cement

Question 19

(T/F) the final impression should be only poured once

Answer 19

false, need to be pour twice so we can get dies and working cast to be mounted

Question 20

should a trimmed die have the same contour as the tooth?

Answer 20

yes

Question 21

how much margin do you need to carve the wax to the proper emergence profile?

Answer 21

5mm to finish line

Question 22

this is used to provide space for cement while cementing final restoration in mouth

Answer 22

die spaces

Question 23

where should a die-spacer be placed?

Answer 23

5mm coronally to finish line

Question 24

this is necessary to orient dies of prepared teeth to the opposing occlusion

Answer 24

interocclusal records

Question 25

allu wax should

Answer 25

not be used for FPD

Question 26

when placing the interocclusal record, where should it be?

Answer 26

between prepped and opposing teeth only

Question 27

this dye system requires less manipulation of wax pattern and reduces chances of breakage and distortion

Answer 27

removable die system

Question 28

epoxy resin is superior to gypsum in terms of

Answer 28

abrasion resistance

Question 29

what is the best interocclusal record materials?

Answer 29

rigid, fast-setting VPS

Question 30

gypsum should be set in what position?

Answer 30

upright position

Question 31

which die system provides a rigid relation for the FPD component

Answer 31

solid cast -die system