8/22 - Retraction cord, Pindex Refresher, Impression Materials (Heavy Emphasis), S5-S8

Question 1

are we doing single or double retraction cord

Answer 1

single

Question 2

about how much a retraction cord do we initially cut off

Answer 2

2 inches

Question 3

placement of retraction cord is begun by pushing it where

Answer 3

sulcus on the mesial surface of the tooth. can also be tacked lightly into distal crevice

Question 4

what are common problems students have when packing cord

Answer 4

1. angulation
2. packing too much cord at a time

Question 5

what angle should cord be packed

Answer 5

30-45 degrees

Question 6

what happens if the force of the instrument is directed away from area previously packed

Answer 6

cord already packed will be pulled outo

Question 7

what to do if cord is not going in when packing

Answer 7

recheck angle

Question 8

can you hold the cord with one instrument and packing it with a second instrment

Answer 8

YES

Question 9

when packing, the instrment should be angled where

Answer 9

towards the root

Question 10

what happens to the retraction cord if the instrument is held parallel to the long axis of the tooth

Answer 10

retraction cord will be pushed against the wall of the gingival crevice and will rebound

Question 11

what is the thinnest retraction cord

Answer 11

000

Question 12

T/F: it’s okay if the retraction cord just goes on side of margin. it does not need to physically go in.

Answer 12

FALSE! needs to physically go in

Question 13

what to do with extra cord

Answer 13

cut it out or keep looping around

Question 14

how long to keep retraction cord in

Answer 14

5-10 minutes

Question 15

do you numb patient when placing retraction cord

Answer 15

YES

Question 16

hardrock cast has ___ mm bevel

Answer 16

3 mm

Question 17

how thick is hardrock cast B-L and O-G

Answer 17

15-18mm

Question 18

short pins [lingual, buccal]
long pins [lingual, buccal]

Answer 18

short = lingual
long = facial

Question 19

what side of pins enter stone, short or long

Answer 19

SHORT

Question 20

gray sleeves on [short, long] pins
black sleeves on [short, long] pins

Answer 20

gray = short
black = long

Question 21

how much flowstone to add

Answer 21

barely cover apical part of bevel

Question 22

how many mm extension of flow stone

Answer 22

3-4 mm

Question 23

how to trim die: start at occlusal or gingival

Answer 23

gingival

Question 24

common mistakes when taking impressions

Answer 24

1. voids and bubbles
2. separation from tray
3. embedded retraction cord
4. prep debris

Question 25

what does "the greater the contact angle, the greater the probability of air entrapment during pouring" in regard to

Answer 25

wettability

Question 26

what do we look at when comparing the different types of ipressions

Answer 26

wettability and cost

Question 27

large angle [bad, good] wetting

Answer 27

bad wetting/hydrophobic

Question 28

acute angle [bad, good] wetting

Answer 28

good/hydrophilic

Question 29

does hydrophilic or hydrophobic have a higher incidence of voids and is more readily repelled by hemorrhage or moisture in the gingival sulucs

Answer 29

phobic

Question 30

is polysulfide, PVS, and condensation silicone hydrophilic or hydrophobic

Answer 30

phobic

Question 31

what is effective in reducing both the contact angle and the number of voids trapped in resuling cast

Answer 31

surfactant

Question 32

is hydrophilic or hydrophobic have a lower incidence of voids and more able to withstand hemorrhage or other moisture in gingival sulcus

Answer 32

hydrophilic

Question 33

is hydrophilic or phobic less resistant to wetting by gypsum

Answer 33

hydrophilic

Question 34

are revesible hydrocolloid, irreversible hydrocolloid and polyether hydrophilic or hydrophobic

Answer 34

hydrophilic

Question 35

what is the decrease viscosity of the material under shear load

Answer 35

shear thinning

Question 36

what is thick enough to stay in tray yet fluid enough to express thru syringe

Answer 36

thixotropic

Question 37

is light-body polysulfide and condensation silicone least or most viscous

Answer 37

least

Question 38

is heavy body sulfide least or most viscous

Answer 38

most

Question 39

what are examples of chemical disinfectants

Answer 39

1. chlorine compounds 2. combination synthetic phenolic compounds 3. glltaraldehydes 4. iodophors 5. phenol-alcohol combinations

Question 40

process of disinfecting impressions

Answer 40

1. rinse 2. trim 3. spray 4. seal

Question 41

what is agar made frmo seaweed

Answer 41

reversible hydrocolloid

Question 42

what is made of 85% water

Answer 42

reversible hydrocolloid

Question 43

what is water seeping rom surface

Answer 43

syneresis

Question 44

what is imbitition

Answer 44

absorbing water

Question 45

what are the risks of using reversible hydrocolloid

Answer 45

syneresis, evaporation, and imbitition

Question 46

when should you pour reversible hydrocolloid

Answer 46

ASAP

Question 47

why do you place reversible hydrocolloid in tempering batch

Answer 47

lowers temp to decrease viscosity and because it's boiling from previous baths

Question 48

sodium tetraborate is also called what

Answer 48

borax

Question 49

modifiers placed in reversible hydrocolloid

Answer 49

1. sodium tetraborate/borax 2. potassium sulfate 3. thymol 4. plasticizers, fillers, flavoring agents and pigmetns

Question 50

since the set of gypsum is retarded by contact w/ any gel resulting in soft surface of cast, what is added

Answer 50

potassium sulfate (to accelerate set-up)

Question 51

irreversible hydrocolloid is also called what

Answer 51

alginate

Question 52

what is inexpensive and has low tear strenegth

Answer 52

irreversible hydrocolloid/alginate

Question 53

what material has less surface detail than other materials

Answer 53

irreversible hydroc

Question 54

what material is not as dimensionally stable as other materials

Answer 54

irreversible hydro

Question 55

how quick to pour irrversible hydro

Answer 55

15 minutes

Question 56

what is an elastomer known as mercaptan, thiokol, or rubber base

Answer 56

polysulfide

Question 57

is polysulfide hydrophilic or phobic

Answer 57

hydrophobic

Question 58

does hydrocolloid or polysulfide have greater dimensional stability

Answer 58

polysulfide

Question 59

what must you do when completing polysulfide impression

Answer 59

block out large undercut areas in inerproximal region with soft wax prior to impression making

Question 59

when must polysulfide impression be poures

Answer 59

within 1 hour

Question 60

what are the two tubes for polysulfide impression

Answer 60

1. base 2. accelerator

Question 61

what is a liquid polysulfide polymer mixxed with an inert filler

Answer 61

base

Question 62

what is usually a lead dioxide mixed wih small amounts of sulfur and oil

Answer 62

accelerator

Question 63

the accelerator in polysulfide is an oxidation iniator on what on the polymer

Answer 63

on terminal thiol groups

Question 64

do polysulfide acelerators have toxicity and tendency to irritate soft tissues

Answer 64

YES

Question 65

does the accelerator show up radioopaque

Answer 65

yes

Question 66

what impression material has a limited shelf life

Answer 66

organo-tin silicones

Question 67

is the two paste system of condensation silicone cross linked by reaction

Answer 67

ys

Question 68

what is a liquid silicone polymer w/ terminal hydroxyl groups, mixed w/ inert fillers

Answer 68

base paste of condensation silicone

Question 69

what is a viscous liquid, cross-linking agents, ethyl silicate with an organo-tin activator in tin

Answer 69

reactor of condensation silicone

Question 70

is condensation silicone dimensionally stable or insable

Answer 70

instable

Question 71

when to pour up condensation silicone impressions

Answer 71

ASAP

Question 72

process of putty/wash or putty/reline

Answer 72

1. heavy body (putty) w/ stock tray and thin plastic spacer 2. thin wash of light body material to reline the putty

Question 73

what is a copolymer of 1,2-epoxyethane and tetrahydrofuran reacted with alpha, beta-unsaturated acid, such as protonic acid to produce esterification of the terminal hydroxyl groups

Answer 73

polyether impression

Question 74

is polyether impression resistant to tearing upon removal

Answer 74

yeS

Question 75

is polyether impression somewhat brittle

Answer 75

yeah

Question 76

is it okay if you dont block out for polyether impression

Answer 76

NO! stiff material so needs to be blocked out

Question 77

people with allergic rxns to polyether are allergic to what

Answer 77

aromatic sulfonate catalyst

Question 78

is polyether hydrophobic or hydrophilic

Answer 78

philic so imbibition likely

Question 79

is polyether accurate when poured weeks after removal from mouth

Answer 79

yes

Question 80

what impression material used in complete denture

Answer 80

polyether

Question 81

what is PVS also called

Answer 81

polyvinyl siloxane, addition silicone, vinyl polysiloxane, and vinl silicone

Question 82

what uses two pastes with mixing dispensers

Answer 82

PVS

Question 83

what are the two pastes in PVS

Answer 83

1. silicone w terminal silane hydrogen groups and inert filler 2. silicone w/ terminal vinyl groups, chloroplatinic acid catalyst, and filler

Question 84

is PVS hydrophilic or phobic

Answer 84

phobic

Question 85

are surfactants added to PVS

Answer 85

yes

Question 86

does PVS have less stability than condensation silicone

Answer 86

NO! it's dimensional stabilit is GREATER than condensation silicone

Question 87

can you use latex gloves when doing PVS impression? why??

Answer 87

no - sulfur impedes material

Question 88

when to pour PVS impression

Answer 88

15-20 minutes after. still accurate after 1 week