10/17 - Removable Dies and Dual-Arch Impressions, 302-306

Question 1

what is a die system involves a separate die together with a working cast

Answer 1

separate die system

Question 2

what system is this

Answer 2

separate

Question 3

what are dies that can be removed from working cast

Answer 3

removable dies

Question 4

advantages of removable dies

Answer 4

Eliminates discrepancies between a separate die and working cast that:
1. may be caused by impression distortion
2. may be caused by deterioration between pours
3. may be caused by a cast and die made from separate impressions that are not identical
4 occur when the die is coated with a relief agent and the working cast is not
5. occur when the die and working cast are coated with differing thicknesses of relief agent

Question 5

principal disadvantage of removable die system

Answer 5

introduction of error in pattern if die does not reseat completely on working cast (introduces a gap)

Question 6

removable die system must satisfy what 3 requirements

Answer 6

1. dies must return to exact original position
2. dies must remain stable when inverted
3. cast containing dies must be easy to mount on an articulator

Question 7

what type of dowel

Answer 7

flat sided single dowel

Question 8

what type of dowel

Answer 8

double dowels

Question 9

what type of dowel

Answer 9

two separate dowels

Question 10

is the flat-sided single dowel capable of anti-rotation?

Answer 10

supposed to but not well

Question 11

are double dowels considered to be one pin or two pins

Answer 11

ONE pin with TWO dowels

Question 12

which dowel is good for narrow teeth

Answer 12

double dowel

Question 13

when technique has pins oriented in the impression before it is poured

Answer 13

prepour technique

Question 14

what technique has pins attached to the underside of a cast that has already been poured

Answer 14

post pour technique

Question 15

what pour technique do we use for pindex system

Answer 15

post pour

Question 16

which die is easy to use but does not provide as much anti-rotational resistance as double dowels

Answer 16

single dies

Question 17

dies that rotate lead to what issues

Answer 17

proximal contact issues

Question 18

what type of die provides more than adequate rotational resistance

Answer 18

two parallel single dies

Question 19

what are single dies also called

Answer 19

brass dowel pins

Question 20

what die is accurate in resisting horizontal displacement

Answer 20

single dies/brass dowel pins

Question 21

how should single dies be positioned?

Answer 21

1. A pin is positioned over each prepared tooth in the impression
2. Must place them accurately (centered in the preparation and not too deep in the prep or too high outside of the preparation)
3. Must be secured in the impression and “above” the preparation

Question 22

what are the different methods of single die placement?

Answer 22

1. Marking the outside of the impression and free-handing the pin into the unset stone
2. Usage of bobby pins along with straight pins and sticky wax
3. Ortho wire

Question 23

how can the second pour of stone be retained to the first pour of impression

Answer 23

paper clips, stables, washers, blobs of stone, etc.

Question 24

what should you place in the removable die area?

Answer 24

separating medium

Question 25

T/F: you can fill the horseshoe area of the impression w/ paper towel or playdough

Answer 25

TRUE

Question 26

advantages of dual arch impression

Answer 26

1. use of one tray capturing impression of prepared tooth, opposing teeth, and bite relationship
2. no need for custom tray
3. less impression material needed (quadrant arch)

Question 27

what is dual-arch impression also called

Answer 27

triple tray

Question 28

disadvantages of dual arch impression

Answer 28

1. only accurately used for single unit posterior restorations w/ intact distal tooth
2. can only be w/ patients w/ Class I occlusion
3. trays/impressions are prone to flexibility (dual arch metal trays better than plastic)
4. distal bar of tray must be able to fit posterior of most distal tooth

Question 29

what type of tray is this

Answer 29

plastic dual-arch impression tray

Question 30

what is this? what is its disadvantage

Answer 30

distal bar -> may interfere with proper closure

Question 31

do you place adhesive on dual arch tray

Answer 31

yes

Question 32

do you load impression materials both sides at once or do you fill top first, take the impression, then bottom, then take the impression

Answer 32

load both sides (top and bottom) at once!

Question 33

what bite relationship should patient have when taking dual arch impression

Answer 33

maximum intercuspation

Question 34

should you see light thru the dual arch impression? why?

Answer 34

yes! it means that the patient bit correctly

Question 35

can you remove either side of the dual arch impression before mounting?

Answer 35

NO! do NOT remove either side until mounting is finished

Question 36

do you pour dual arch impressions both at a time?

Answer 36

no - do one side at a time