class I and class V prep fundamentals

Question 1

principals of tooth prep for amalgam restorations.
-have a means for ISOLATION of the site:
1
2
3

Answer 1

1. visibility
2. access
3. moisture control (composite resin)

Question 2

isolation prep
a gold standard
b
c
d

Answer 2

a. rubber dam
b. cotton rolls
c. retraction cord
d. isovac

Question 3

dentin must support all

Answer 3

surface of enamel

Question 4

margins should be ______ at the cavosurface on ALL axial surfaces

Answer 4

90 degrees

Question 5

on the occlusal surface, margins may be slightly obtuse in some areas, but never ______ anywhere or enamel will break

Answer 5

never acute enamel will break

Question 6

ideal preps are ______mm into dentin
(in live patient, determined by carie)

Answer 6

.2 to .5mm

Question 7

amalgam doesn’t bond to tooth structure
smaller amalgams are held in by ________or_____ if no walls cant converge

Answer 7

converging walls or retention grooves

Question 8

these are elements in the design of a tooth preparation that will help both restoration and tooth resist fracturing.
1. maintaining as much too structure as possible makes =

2. having some areas on the floor of a multisurface PERPENDICULAR TO OCCLUSAL FORCES make

Answer 8

1. makes the tooth less likely to fracture
2. makes restoration less likely to fracture

Question 9

____ internal line angles on prep make tooth less likely to fractice

Answer 9

rounding

Question 10

___ rounding outlines make restoration less likely to fracture

Answer 10

smoothly rounding outline

Question 11

preparing to PROPER DEPTH prevents weakness (resist fracture) in :

Answer 11

The restoration

Question 12

never leave what on the floor of an amalgam prep

Answer 12

enamel

Question 13

never leave what on the enamel wall of an occlusal prep like class I amalgam

Answer 13

partial depth ledge

Question 14

leaving sharp external line angles under amalgam that is subject to occlusal stress can lead to
ex. axial wall of class II prep

Answer 14

fracture of restoration

Question 15

buccal pit amalgam is class

Answer 15

class I

Question 16

occurs in occlusal 2/3 of molar tooth
restores developmental pit

Answer 16

buccal pit amalgam

Question 17

walls at terminal ends of buccal and lingual grooves ____ 3 degrees

Answer 17

diverge

Question 18

walls in isthmus areas ____ 3 degrees on each side of prep. isthmus width is

Answer 18

converge
1mm minimum

Question 19

walls adjacent to marginal ridges ___ 3 degrees

Answer 19

diverge

Question 20

diverging m or d wall adjacent to marginal ridge leaves __________ for ridge in this area

Answer 20

leaves dentin support

Question 21

occlusal amalgam depth:
____ mm inside DEJ
plastic molars 2 mm total
plastic premolars: 1.5 mm total

Answer 21

.2mm

Question 22

burr inclines more mesially in _____ and more distally in ____ the further posteriorly we go do to the curve of ____

Answer 22

mesially: mandible
distally: maxilla
curve of spee

Question 23

burr inclines more lingually in the ____ and more buccally in ____ the more posterior we go due to the curve of

Answer 23

lingually: mandible
buccally: maxilla
curve of wilson

Question 24

class I occlusal amalgam prep procedure
1. insert bur to depth of
2. hold burr ____ to occlusal plane
3. keep prep as ___ as possible-just the width of bur (stop in M and D pits)

Answer 24

1. 1.5 mm with bur
2. bur perpendicular to occlusal plane
3. narrow as possible

Question 25

169-

330 and 245

Answer 25

169- diverging 4mm sharp edges
330 and 245- converging 245 is 3mm

Question 26

169 enter to

then with 245 burr

Answer 26

169 go to 1.5

245 insert to depth of 2mm (molar) 1.5 (premolar)

Question 27

if this bur is held in one plane, it will cut an ___ prep with ____ internal line angles

Answer 27

undercut prep
rounded internal line angles

Question 28

restores carious lesions on gingival 3rd of B and L surfaces of teeth

Answer 28

class V

Question 29

almost all carious lesions begin:

but often spread subgingivally onto root surface

Answer 29

supragingivally

Question 30

with class V, retention grooves are always in ____ just inside the DEJ

even when axial wall is deeper than ideal due to caries

Answer 30

in dentin

Question 31

gingival retention groove:

Answer 31

occlusal retention groove at occlusal-axial line angle

Question 32

enamel in what area is thinner and prep is not as deep as an occlusal amalgam

Answer 32

thinner at cervical area

Question 33

since the prep in class V is in smooth area, outline form is determined by___
rather than following anatomy

Answer 33

the extent of the carie

Question 34

since class V prep is in CONVEX surface and all amalgam margins must by 90 degrees, all walls ____

Answer 34

DIVERGE

Question 35

in class V prep, the axial wall is ___ when caries in minimal

Answer 35

convex

Question 36

2 retention grooces in class 5 amalgam

Answer 36

occlusal-axial retention groove
gingival-axial retention groove

Question 37

entire thickness of enamel is _____ to the cavosurface and is still supported internally by dentin

Answer 37

perpendicular

Question 38

with class V, want uniform depth of

Answer 38

1.5
all walls diverging in class V

Question 39

when caries extend on to root surface/subgingival the rules for DEPTH change:

Answer 39

-when there is minimum thickness of enamel: 1mm depth
-when margin is on root: .75mm depth
-for this class: 1.5mm

Question 40

1/4 round burr used to place occlusal and gingival rention grooves entirely:

Answer 40

into dentin just inside DEJ

(with deep preps, grooves still go in dentin just inside DEJ)