Lecture midterm Flashcards
(155 cards)
1
Q
two cavities should not be combined unless the separating ridge is less than
A
0.5mm
2
Q
when can you extend into the oblique ridge of 1st maxillary molars
A
if its undermined by caries
3
Q
isthmus width should not exceed ____ intercuspal distance
A
1/3
4
Q
what depth into dentin should a cavity prep be
A
0.2-0.5mm
5
Q
why do we prep cavities with converging buccal and lingual walls?
A
follows direction of enamel rods
6
Q
how much of the marginal ridge should be conserved
A
1.6mm
7
Q
prevents dislodgment of the restoration by lifting or tipping
A
retention form
8
Q
increased surface area helps to increase friction for what cavity prep feature
A
retention form
9
Q
opposing walls slightly converging is what type of prep feature
A
retention form
10
Q
sufficient access to the cavity is what type of prep feature
A
convenience form
11
Q
why is convince form import for visibility
A
removal of all decay
12
Q
needs for access to the prep for instruments
A
convenience form
13
Q
important prep feature to achieve the best marginal seal
A
finishing
14
Q
removing jagged edges or rough outline is what type of prep feature
A
finishing
15
Q
the final step before the prep receives restorative material
A
Debridement
16
Q
rising the cavity with air/water spray and high suction
A
Debridement
17
Q
removes smear layer from cavity prep
A
Debridement
18
Q
dental shavings on cavity preparation
A
smear layer
19
Q
remove moister (blood & saliva) from prep
A
Debridement
20
Q
the junction between the external walls of the cavity preparation and the uncut tooth structure
A
cavosurface margin
21
Q
the shape of the cavity preparation
A
outline form
22
Q
what are the three factors that govern outline form
A
conservation of tooth structure
location & extend of caries
position of pits & fissures
23
Q
unnecessary loss of healthy tooth structure
A
extension for prevention
24
Q
preservation of remaining tooth structure- minimal extension
A
conservative approach
25
removal of carious area and any weak enamel
outline form
26
Helps the restoration to withstand the forces directed towards the long axis of the tooth
resistance form
27
primary resistance features
```
removal or undermine enamel
flat floor
adequate depth
well defined line angles
type of restorative material
```
28
cavosurface margin should not terminate on unsupported enamel
resistance form
29
minimum amalgam thickness to withstand forces
1.5mm
30
what makes the amalgam margin angle & smoothness so important
low edge strength
31
taper of a 330 bur
8 degrees
32
tapper of a 245 bur
4 degrees
33
what shape burs are 229-330
pear
34
length of 330 bur
1.5mm
35
length of 245 bur
3.0mm
36
diameter of 330
0.8mm
37
diameter of 245
0.8mm
38
not efficient at cutting ductile material (dentin)
abrasives / Diamond
39
recommend for intracoronal preparations
bladed cutting
40
force applied perpendicular to cutting edge
direct cutting
41
force applies parallel to the cutting edge
indirect cutting
42
can do lateral and direct cutting
enamel hatchet
43
cutting edge makes an angle to the long axis of the blade
marginal trimmer
44
what is a lesion caused by mechanical factors
none carious lesion
45
what rotary instrument runs at 12,000 - 20,000 rpms
Medium speed
46
type of bur that is used for extracoronal preps
diamond
47
In OSU's lab do we use negative or positive rake angle burs?
negative
48
These burs are efficient at cutting but get clogged and break easily
Postive rake angle
49
Bur cuts by shearing layers of tooth structure
Bladed
50
Bur cuts by removing a mono layer
Diamond
51
The hard but brittle material that is used to make bladed burs
tungsten carbide
52
A bigger ____ angle created less friction on the tooth
clearance
53
Not for cutting just refining the cavity prep
Hand instruments
54
In hand instruments creates balance and directs the forces onto the cutting angle
contra angle
55
why don't we use mono angle instruments in the mouth
forces out of balance
56
Rotary instrument that turns at a rate below 12,000 rpms
slow speed
57
Rotary instrument that turns at a rate above 20,000 rpms
high sleep
58
Besides cavity preps what is another use for the high speed instrument
removing old restorations
59
why is the neck of the bur constricted
visibility
60
A large number of blades on a bur give the prep a. . . .
smooth finish
61
dental Material is place in a soft state and contoured before it sets
Direct restoartion
62
Restoration is fabricated outside of the oral cavity then cemented or bonded to the tooth
indirect restoration
63
The clearance face is in front of the axis line (of the bur)
postive
64
how many surfaces does a compound cavity prep involve
2
65
how many surfaces does a complex cavity prep involve
3
66
what is a class 1 prep?
Pits and fissures
67
what angle should the cavosurface margin be?
90 degree
68
Cariesclassification: occlusal surface of premolars and molars; buccal or lingual pits/ fissures of the molars; lingual pit near cingulum of maxillary incisors
Class I
69
Caries classification: Proximal surface (mesial and/ or distal) of premolars and molars
Class II
70
Caries classification: Proximal surface (mesial and/ or distal) of incisors and canines
Class III
71
Caries classification: Proximal surface of incisors and canines but also the incisal edge
Class IV
72
Caries classification: Gingival third of the facial or lingual surface on any tooth
Class V
73
Caries classification: involve the inciscal edges of anteriors or cusp tips of posteriors
Class VI
74
cutting motion from beveled to non beveled edge of a hand instrument
Lateral / indirect cutting
75
Cavity prep principle: smooth pulpal and gingival floor provides
resistance form
76
Removing undermined enamel from the cavity preparation provides
resistance form
77
Ideal isthmus width is ______ of the intercupsal distance
1/4 - 1/3
78
Ceramics are
brittle
79
ceramic mimic what part of the tooth
enamel
80
gold is
ductile
81
Gold mimic what part of the tooth
dentin
82
Dentin provides ____ that helps to adjust to condensing
elasticity
83
why do we drill 0.05mm into dentin
elastic recoil
84
The dove tail feature is
retentive
85
Minimum isolation for a rubber dam is ____ posteriorly and _____ anteriorly
1, 2
86
All line angles of a class V prep are
divergent facially
87
The prongs of a clamp on the rubber have to be touching _____ line angles
all four
88
The tip of the hole back should be placed in ___ during carving
central groove
89
Is done because the softest phase of amalgam stays on top
overfilling
90
what needs to be done with the top layer of over filled amalgam
carved away
91
Why is the top phase of the amalgam filling softer
mercury rich
92
What need to be done if the amalgam filling has an open margin
redone
93
What need to be done if the amalgam filling is submarginal
enameloplasty
94
Are open margins sealed?
No
95
Are submerging sealed
just shy (.2)
96
Has to be removed from the filling with a finishing bur
flash
97
Admix - blend of lathe cut and spherical particles
Permite C
98
When the membrane of the amalgam capsule is ruptured what happened
mercury in contact with alloy
99
Process by which mercury is allowed to react with the alloy powder
Trituration
100
Trituration
Amalgamation
101
How long should the amalgamator be set
7/8 seconds
102
Amalgam that is soupy, difficult to remove
Over Trituration
103
Excess matrix is formed in
Over Trituration
104
Soft shiny, warm
proper mix
105
Amalgam that is grainy, is dull and crumbles
Undertrituration
106
under triturated amalgam has
reduced strength
107
under triturated amalgam is
hard to handle
108
Amalgam that has optimal properties
proper Trituration
109
The process of compressing the allot into the tooth preparation and eliminating voids
condensation
110
Force / area =
pressure
111
A shiny rich mercury phase viable and you'll head a crunch
adequate condensing
112
From the center to periphery
condensing
113
Which end of the condenser should be used as you approach the external surface of the tooth
large
114
In what time frame (for permite C) should condensing be completed?
3-4 minutes
115
Should the last increment of amalgam extend over the preparation?
yes (1mm)
116
How should amalgam be added to the cavity preparation
in increments
117
using the round face of the condenser either perpendicular to the long axis or axis at 45 degrees
vertical strokes
118
using the side of the condenser either parallel to the long axis of at 45 degrees
lateral storkes
119
Type of stroke used solely in class I preps with extensions or in proximal boxes
lateral / horizontal strokes
120
over filling is done to extract ____ from the preparation
mercury
121
over filling helps to
seal the margins
122
What can form if condensing goes beyond 3-4 minutes
cracks in matrix
123
used between condensing and final carving
anatomical burnisher
124
Carving instruments should always be resting
partially on tooth structure
125
Used to define the developmental grooves
push stroke
126
High gentle pressure moving the carver parallel to the margins
pull stroke
127
Motion from tooth structure to amalgam
push stroke
128
Carving is done of two planes for this prep
Class V
129
What are the two planes of carving for the Class V prep
gingival and occlusion
130
Over-contoured cusps, shallow central groove, shallow fusses and high occlusal contract are a result of
under carving
131
Deep central groove, steep triangular ridges, deep marginal fossas are result of
over carving
132
Break between tooth and the amalgam restoration / not continuous
open margin
133
The seal between the alarm and the enamel is not broken (<0.2mm)
submarginal
134
if the gap is marginal > 0.2mm
restoration needs replaced
135
When the patient bites down this will be broken easily
flash
136
If the tip of the explore catches from tooth to amalgam and not from amalgam to tooth structure at the margins
flash
137
Marginal voids due to inadequate condensation
open margins
138
How do you fix open margins
re do
139
Tip of the explorer catches when moved in both directions across the margin
open margin
140
Tip of the explorer catches when moved form amalgam to tooth but not from tooth to amalgam at the margin
submarginal
141
Serves to substitute to conventional polishing, can help to improve marginal integrity
post carve burnishing
142
A moist cotton tip applicator to clean the surface from minute scrap and debris
Cleaning surface
143
Should occlusion be checked before after removal of rubber dam
after
144
Ideal occlusion mark are on the _____ cusps and the _____
functional, marginal ridge areas
145
Clinically gingival clearance for a proximal box
0.5mm
146
In typodonts the proximal contacts are more
occlusal
147
In a class V prep the wall that runs parallel to the root axis is the
axial wall
148
the diameter of the 1/4 round is
0.5mm
149
The distance from the external surface to the axial wall
axial depth
150
Axial depth on the crown of a Class V prep
1.0 -1.25mm
151
Axial depth on the root of a Class V prep
0.75mm
152
What is the primary mechanical retention of a class V prep
there is none
153
Because there is no primary mechanical retention of a class V prep we add
retention grooves
154
The incised, gingival, mesial and distal walls of a class V prep are all
divergent
155
What is the retention groove call
auxiliary/ secondary retention
