Midterm Flashcards
(202 cards)
1
Q
-distal wall
-facial wall
-lingual wall
-gingival wall
These are all:
A
external walls
2
Q
-pulpal floor
-axial wall
These are both:
A
internal walls
3
Q
What is the thickness gauge of the heavy dental dam (pretty sure this is the one we use):
A
.010”
4
Q
The parts of the retainer (clamps) used with a dental dam include: (4)
A
- bow
- jaws
- forceps holes
- points
5
Q
Isolation of operating field is extremely important because a wet field=
A
recurrent caries or failed bond
6
Q
For isolating the operating field for a class II, what teeth would show through the dental dam?
A
One tooth posterior, two teeth anterior to the tooth you’re working on
7
Q
The tooth posterior to the tooth you’re working on that is clamped, when using a dental dam is considered the:
A
anchor
8
Q
What are your isolation options when damming anterior teeth?
A
- canine to canine
- clamp on one premolar
9
Q
Sometimes the rubber dam will not work, especially in cases with _____ medications (rarely used)
-give example of these medications
A
antisialogogue
-atropine
-banthine
10
Q
What instruments are used to remove caries, once outline form is achieved?
A
- spoon excavator
- round bur on slow speed handpiece
11
Q
When refining an amalgam class II preparation, why should you plane/bevel the axiopulpal line angle?
A
reduces stress
12
Q
When refining an amalgam class II preparation, why should you plane/bevel the gingival margin?
A
This removes loose enamel rods
13
Q
When placing the wedge with use of a matrix band, what side should the wedge be inserted?
A
Place wedge from larger embrasure
14
Q
In a class II amalgam restoration:
- fill ____ first
- fill _____ above margins
- carve _______ of marginal ridge using explorer
- pre- _______
- carve with _____
A
- box
- 1.0mm
- mesial incline
- pre-carve burnish
- hollenback
15
Q
What should you do while removing the matrix band in an amalgam class II restoration?
A
Hold condensor on marginal ridge as you gently remove the band
16
Q
In the proximal outline form of a class II composite restoration, you must break:
A
gingival margin
17
Q
In a class II composite restoration, where should you keep the margins when possible?
A
In enamel
18
Q
In the proximal outline for a class II composite restoration, the ____ contact should always be broken, while the _____ contact may or may not be broken
A
lingual; buccal
19
Q
Is a reverse S curve necessary in a composite restoration?
A
no
20
Q
What bevels are involved in a class II composite restoration?
A
- lingual wall bevel
- gingival bevel
- axial-pulpal line angle bevel
21
Q
In what case would you not do a gingival bevel in a class II composite prep?
A
if gingival floor is in dentin/cementum
22
Q
It is more challenging to establish a good contact with a class II _____ restoration
A
composite
23
Q
What additional steps are needed in a class II composite restoration compared to amalgam? (4)
A
- etch & rinse
- bond
- incremental placement of composite
- light cure each increment
24
Q
For a complete etch:
- place etch on ____ first, followed by ____
- etch _____ for 20-30 seconds
- etch _____ for 15-20 seconds
- rinse & gently ____
A
- enamel; dentin
- enamel
- dentin
- air dry
25
What type of etch is typically only done with total-etch and universal bond agents?
complete etch
26
With selective etch, what is etched and how long?
enamel only; 20-30 seconds
27
What bonds agents allow you to selectively etch?
1. universal (what we use in clinic)
2. self etch
28
What is considered evidence of etched enamel?
Whitish etched enamel surface
29
Results in collapse of collagen layer and reduced bond strengths:
desiccation of dentin
30
What are typically the solvents in bond agent?
(these evaporate when you gently blow air)
1. acetone
2. ethanol
3. water
31
The most important increment in a class II composite restoration (also the first increment) is at:
gingival wall
32
When adding the additional increments after the first composite increment (1 mm), you should NOT exceed ____ mm of material per increment.
2 mm
33
By starting with 1 mm increment of composite and then not exceeding 2 mm on additional increments, this method minimized ____ placed on the material and on the tooth due to _____
stresses; polymerizaiton shrinkage
34
A flat marginal ridge would _____ (and this is why it should be rounded)
shred floss
35
Finishing and polishing composite functions to:
1. removes _____
2. establishes _____
3. ensures ____
1. oxygen inhibited layer
2. anatomy/final shape
3. a smooth surface
36
What is one MAJOR difference between amalgam & composite restoration steps?
Finishing & polishing
37
A _______ is nearly always done on the buccal side of a class II amalgam preparation
Reverse S curve
38
A reverse S curve in a class II amalgam preparation, improves:
resistance to amalgam fracture
(because it keeps the narrowest part of prep away from the axiopulpal line angle)
39
In a class II amalgam preparation this feature allows the preparation to break contact while allowing the buccal wall to meet the tooth surface AT A 90 DEGREE EXIT ANGLE:
Reverse S curve
40
Wall clearances around a class II amalgam preparation:
1. buccal contact is open:
2. lingual contact is open:
3. gingival contact is open:
1. (0.2-0.5mm)
2. (0.2-0.5mm)
3. atleast (0.5mm)
41
Enamel rods in a class II amalgam preparation box are inclined:
gingivally
42
In a class II amalgam preparation, an "early" reverse S curve (starts too distally) will result in:
weakening the cusp
43
In a class II amalgam preparation, a flared to mesially reverse S curve (Late reverse S curve) leaves the amalgam prone to:
fracture
44
What type of S-curve error in a class II amalgam preparation leaves the narrow part of prep adjacent to axiopulpal angle; and makes box walls flare causing obtuse cavosurface angles (weakening amalgam):
NO reverse S-curve
45
In a class II amalgam preparation, a concave axial wall with indistinct internal line angles compromises:
Resistance and retention form
46
What are some contraindications to composite restorations?
1. occlusion???
2. restorations extending to root surfave
3. deep subgingival margins
47
When comparing amalgam restorations to a composite restorations, the ______ may be more forgiving, but the ____ is not
preparation more forgiving; restoration not
48
What type of restoration material has the disadvantages of porous & low modulus of elasticity?
Composite
49
The sticky uncured layer left on the surface of a composite restoration:
oxygen inhibited layer
50
What are some new aspects you have to consider with composite (opposed to amalgam):
1. interproximal contacts (he says its harder to achieve these)
2. voids
3. light
4. polymerization stress
51
What step removes the oxygen inhibited layer of a composite restoration?
Finishing & polishing
52
What increases the longevity of a composite restoration?
Polishing & finishing
53
What is the metal adjustable twisty part of the tofflemire called?
tofflemire retainer
54
What are the two types of tofflemire retainers called?
1. straight retainer
2. contra-angle retainer
55
Inserting band into the tofflemire retainer:
1. turn the inner nut _____ until slot vice is about ____ from the guide channels
2. Hold the inner nut and turn the outer nut _____ until the pointed end of the spindle is free in the slot in slot vice
3. double the band back on itself forming a loop
4. insert into the slot vice through one of the three guide channels then tighten the spindle
1. counterclockwise; 1/4 inch
2. counterclockwise
56
When using a tofflemire matrix, the wider opening in the loop is toward the ____________
The slot vice is toward the ______
Occlusal; gingival
57
What is the most common orientation of the tofflemire band?
Most common: retainer on buccal side
Choice 2: retainer on lingual side
58
When carving amalgam, try, if possible to carve anatomy so that the _____ in maximum intercuspation is in the ____. This will put _____ on the teeth
occlusal stop; bottom of the fossa; long axis forces
59
Bonding mechanism in which penetration of the resin and formation resin tags within the tooth surface:
Mechanical bonding
60
Bonding mechanism in which chemical bonding to the inorganic components (hydroxyapatite) or to the organic components (mainly type I collagen) of tooth structure:
Adsorption bonding
61
Bonding mechanism in which precipitate of substances on the tooth surfaces to which resin monomers can bond chemically OR mechanically:
Diffusion bonding
62
Acid etching of enamel for 15 sec with 37% _____ is considered enamel bonding, also known as _____
phosphoric acid; adhesion
63
What is the fundamental mechanism of enamel bonding?
the formation of resin microtags within the enamel surface (roughing up surface creating high surface energy)
64
Primarily relies on the penetration of adhesive manomers into the filigree of collagen fibers left exposed by etching with 37% phosohoric acid for 15 sec:
Dental bonding (adhesion)
65
Compare the strength of dentin bonding to enamel bonding:
Dentin bonding is weaker
66
Smear layer= cut ______ surface composed of debris of hydroxyapatite crystals & dentatured collagen
smear layer
67
The smear layer decreases dentin permeability by:
85%
68
Describe the types of etching:
1. no phosphoric acid
2. phosphoric acid on enamel
3. phosphoric acid on enamel & dentin
1. self-etch
2. selective-etch
3. total-etch
69
When you use total etch (on enamel & dentin) you remove the smear layer and this can sometimes cause:
sensitivity
70
Self etch & selective etch leave the ____ in place because you're not etching the dentin
smear layer
71
The state in which two surface are held together by INTERFACIAL FORCES which may consist of valence or interlocking forces or both:
adhesion
72
A material, frequently a viscous fluid, that joins two substrates together by solidifying & transferring the load from one surface to another:
adhesive
73
the measure of the load-bearing capacity of an adhesive joint:
adhesive strength
74
What factor of adhesion allows the availability of substrate to interact with adhesive?
a clean substrate
75
What factor of adhesion allows the adhesive to maintain intermolecular contact with dental surface?
wetting ability
76
Acid etching= increases surface free-energy= ______
improves surface wetting
77
Spreading capacity of adhesive onto dental surface:
viscosity
78
Viscosity depends on the surface tension of:
Tension of liquid (adhesive)/ of the substrate
79
surface roughness- irregular surface increases the bonding ability by:
1. increases area for bonding
2. increases adhesive interlocking
80
increases the surface available for bonding and intermolecular contact with adhesive:
acid etching
81
Penetration of resin adhesive and formation of hybrid layer/ or resin tags within the tooth surface after polymerization - entanglement=
mechanical bonding
82
micro-mechanical interlocking within the tooth surface:
Resin tags
83
Chemical bonding to the inorganic component (hydroxyapatite) or organic components (mainly type I collagen) of tooth structure:
Chemcial/adsorption bonding
84
Precipitation of substances on the tooth surfaces to which resin monomers can bind mechanically or chemically:
Diffusion bonding
85
What are the mechanisms of bonding (4):
1. mechanical
2. chemical/adsoprtion
3. diffusion
4. combination
86
-97% mineral (mainly hydroxyapatite)
-1-2% orgnanic (amelogenin & enamelin)
- 2% water
Composition of enamel
87
Origin of enamel:
epithelial
88
The structure of enamel is:
Prisms
89
Enamel can be described as a ______ substrate
homogenous
90
The bond strength of dentin can be described as:
unpredictable
91
The origin of dentin:
Conjunctive
92
- ~55% mineral (mainly hydroxyapatite)
-30% organic (mainly type I collagen)
- 15-20% water
Composition of dentin
93
What is the structure of dentin?
Tubular
94
Dentin can be described as a _____ stubstrate
very heterogenous (challenging)
95
Chemical "drilling":
acid ethcing
96
Fundamental mechanism of adhesion requires what bonds?
Micromechanical bonds
97
A type of etching pattern on enamel described as "honeycomb" & accompolished through dissolution of prism cores
Type I
98
A type of etching pattern on enamel described as "cobblestone" & accomplished through dissolution of prism peripheries:
Type II
99
Occlusal & middle thirds of teeth is where what types of etching patterns are best accomplished?
Type I & II
100
A type of etching pattern on enamel which is a combination of I & II:
Type III
101
A type of etching pattern on enamel described as "pitted":
Type IV
102
A type of etching pattern on enamel that can be described as "prismless" & flat/smooth:
Type V
103
____ & ____ enamel allows for the bonding performance to have stronger retention & be more predictable
incisal 1/3 and middle 1/3
104
Location of prismless enamel where there are fewer and shorter resin tags after bonding:
cervical 1/3
105
Gingival floor beveling in enamel in class II preparations allows for the reduction of:
microleakage at cervical & ascending walls
106
T/F: You want to bevel the gingival floor in a deep class II prep
False- probably no enamel present once you get that deep
107
When do we not bevel the gingival floor?
Deep class II preps
108
Critical area to bond to enamel include:
Perpendicular prisms
109
As we know perpendicular prisms are a critical area to bond to enamel, where might we find these areas?
1. cavosurface margins class I prep
2. bevels of class II preps
3. ends of enamel rods
110
-fluid filled
-enclosed cellular extensions (odontoblasts)
-connect pulp to DEJ
dentin tubules
111
What type of dentin is being described?
-higher organic content
-collagen rich zone
intertubular dentin
112
What type of dentin is being described?
-surrounding the tubules
-highly mineralized
peritubular dentin
113
Dentin tubule get larger as you near the:
pulp
(because more fluids & less intertubular dentin)
114
Impairs effective bonding so it must be removed with acid etch:
smear layer
115
After acid ethcing _____ are exposed
Adhesive penetrates the encapsulates of _____
Collagen fibrils (both)
116
After polyerization of collagen fibrils by adhesive, this creates an intermingled layer of collagen + resin called the:
hybrid layer
117
The key for dentin bonding & the base for all composite restorations:
Hybrid layer
118
stability & longevity of composite restorations relies on the stability of:
Hybrid layer (collagen + ahdesive resin)
119
agents that bond (micromechanically and/or chemically) the restorative material (or luting agent) to tooth substrate through an interface:
adhesive systems
120
What adhesive technique would you use for a class I-VI carious lesion, traumatic defects and other aesthetic restorations like full or partial resin veneers?
Direct restoration technique
121
The primary in an adhesive system is _____ while the adhesive bonding resin/agent is ____
hydrophilic; hydrophobic
122
What are the three steps to the polymerization process?
1. adhesive/primer (involves a chemical reaction)
2. reaction (activator converts initiators into free radical that starts polymerization reaction)
3. light (activator)
123
Our light activator in the polymerization process is _____ & our initiator is _______ & _____
blue light; camphoroquinone (photosensitizer) & DMAEMA (amine)
124
Self etch (compared to etch & rinse) is good for:
dentin
125
Self etch is not chemically compatable with:
Dual cure composites
126
A material containing atleast two components (phases) with distinct chemical & physical properties that after blended show unique and SUPERIOR PROPERTIES as compared to the individual components:
composites
127
Tooth-colored restorative material containing an organic resin matrix phase (monomers) reinforced by dispersed filler particles phase bound to the resin by a silane coypling agent and initiator-accelerator system:
dental composite
128
What is the coupling agent in dental composite:
silane
129
What is the organic phase of dental composite:
resin matrix
130
What is the inorganic phase of dental composite:
fillers
131
Uses and application of dental composites:
1. Tooth-colored restorative material (direct or indirect restorative technique)
2. bonding agents (filler may be present)
3. sealants (filled)
4. composite resin luting agents (cement)
5. resin-modified glass ionomer materials
6. light-activated liner material
7. CAD/CAM blocks
8. resin endodontic sealers, etc.
132
What are the components of dental composite? (5)
RFCAP
1. resin matrix
2. filler particles
3. coupling agent
4. activator-initiator system
5. pigments and other components
133
Bis-GMA & UDMA are types of:
Resin matrix
134
Describe resin matrixes Bis-GMA & UDMA (3):
1. high molecular weigh monomers (diluents necessary) (BisGMA)
2. Low viscosity
3. Low flexibility
135
TEGDMA is a resin matrix that is a high fluid monomer and used as a diluent for high molecular monomers such as BisGMA.
The amount of TEGDMA=
Polymerization shrinkage
136
Bis-GMA
TEGDMA
UDMA
These are all:
Difunctional monomers
137
Bis-GMA
TEGDMA
UDMA
In these difunctional monomers, the two reactive ends allow for:
Cross-linking
138
Crystalline silica (quartz)
Ba
Li
Al silicate glass
Amorphous silica
These are all:
Filler particles
139
-Dispersed in resin matrix
-Distribution varies depending on the material
-Percent expressed by eight or by volume
Filler particles
140
The benefits for filler particles include:
1. reinforcement of ________
2. DECREASED ________
3. DECREASED _____ & _____
4. _____ control
5. DECREASED _____
6. INCREASED ______
1. resin matrix
2. polymerization shrinkage
3. thermal expansion & contraction
4. viscosity
5. water sorption
6. radiopacity
141
The bond between the two phases of composite:
Coupling agent
142
Silane functions as a _____ in dental composites:
silane
143
Strongly binds the filler to the resin matrix:
Interfacial bridge (from coupling agent)
144
Allows for better stress distribution between resin matrix and filler particles:
coupling agent (silane)
145
improve mechanical properties and decreases water sorption along filler-resin interface:
coupling agent (silane)
146
Composites need to be converted from monomers to polymers and this process is triggered by _____ (from ______)
free radicals
(chemical activation, heat or light)
147
activator= tertiary amine
initiator= benzoyl peroxide
Together these = free radicals
chemical or self-cure
148
activator= blue light (465 nm)
initator= camphoroquinone (photosensitizer) & DMAEMA (amine)
Together these = free radicals
light-cured
149
-prevents spontaneous polymerization
-stops polymerization from brief light room exposure (reacts with free radicals)
polymerization inhibitor
150
Once the blue light is used, all the inhibitor is quickly consumed =
polymerization chain reaction starts
151
What increases the shelf life of the composite resins?
polymerization inhibitor
152
Butylated hydroxytoluene (BHT) and hydroquinone are both:
polymerization inhibitors
(BHT is a food preservative that reduces oxidation)
153
Optical modifiers =
pigments & opacifiers
154
Metal oxides:
pigments
155
-titanium and aluminum oxide
-control opacity or translucency
-brand differences
-dentin vs enamel composite shades
these are all:
opacifiers
156
Composites are classified based on: (3)
1. filler particle size & size distribution
2. handling characteristics
3. type of polymerization
157
Classification by filler size & distribution (categories): (4)
1. macrofill
2. midfill
3. microfill
4. hybrids
158
The hybrid fillers include: (3)
1. mid-micro hybrid
2. mini-micro hybrid
3. mini-nano hybrid
159
What type of fillers are not used much today
(due to rough surface finish, poor size distribution & prone to staining)
macro & midfill composites
160
- (0.01-0.1) micrometer particals, colloidal silica (40-60 wt%)
-excellent finish
-low mechanical and hardness surface properties
-use for esthetic, low-stress sites
microfill composite
161
-High strength
-universal composites (anterior & posterior)
hybrid composites
162
Resin matrix with:
-high molecular weight (need diluents)
-LOW viscosity
-LOW flexibility
Bis-GMA
UDMA
163
Resin matrix with:
-high fluid monomer
-functions as a diluent for Bis-GMA to improve consistency
-amount of this resin matrix is related to polymerization shrinkage
TEGDMA
164
What allows filler particles to have increased radiopacity?
-barium
-stronium
-zirconium
165
Higher filler amount reduces _____ and _____
thermal expansion
contraction coefficients
166
With use of a filler, the reduced shrinkage is proportional to the:
filler volume
167
Brands Adaptic & Concise are ____ & ___ composites that are still on the market
macro; midi
168
Durafill VS, Epic TMPT, Renamel & Heliomolar are all brands of:
microfill composite
169
The first hybrid composites were:
Midi-Micro hybrids (they were called microhybrids)
170
Z250, Z100, Herculite, TPH, APH, & Point 4 are all brands of:
Hybrid composites
171
-Newer filler material
-smoother finish than midi-micro hybrids
-slightly lower strength
Mini-micro hybrids
172
What type of composite filler do we use in lab?
What is another brand name for this?
TPH3
Filtek Supreme Ultra
173
Composite can be classified by handling characteristics, these include:
(3)
1. regular
2. flowable
3. bulk fill
174
A low viscosity and hybrid reduced filler with decreased modulus & increased flexibility that adapts better without handling:
Flowable composite
175
_______ is used under conventional composite at gingival floor of Class II
Flowable
176
A big problem with flowable filler is that many are not ______ making them difficult to distinguish from _____
radiopaque; recurrent caries
177
Composite formulation that is highly filled with pre-polymerized particles, larger size fillers, and has more translucent filler particles:
Bulk fill composite
178
What is required with bulk fill composite?
need high output lights
179
-supposed to be handled like amalgam
-bulk cure inadequate
-not well-accepted (due to fracture at marginal ridges, changes on surface texture & color match)
Packable/Condensable composite
180
What type of curing process is being described below?
-activator: aromatic tertiary amine
-initiator: benzoyl peroxide (BPO)
-advantage: bulk placement
-disadvantages: mixing (could allow for bubbles, decreases strength), no control of working time, amine not color stable
chemical cure
181
What type of curing process is being described below?
-activator: blue light
initiator: camphoroquinone & DMAEMA
-advantages: no mixing required, aliphilic amine (DMAEMA) is more color stable, better control of working time
-disadvantages: limited penetration, takes 20 sec for each increment, retina damage
Light cure
182
Reaction of polymerization (Free radical reaction):
-activator converts initiator into a free radical
activation
183
Reaction of polymerization (Free radical reaction):
-free radical initiator starts the addition reaction
initiation
184
Reaction of polymerization (Free radical reaction):
-continued polymer chain growth
propagation
185
List the steps (in order) of the Reaction of polymerization (Free radical reaction): (4)
1. activation
2. initiation
3. propagation
4. termination
186
Visible light is:
Electromagnetic radiation
187
The visible light spectrum ranges from: (include wavelengths)
Red (700-750nm) to violet (390-400 nm)
(note: camphoroquinone is around 420-510nm max=468)
188
The radiant value divided by the tip area:
irridance value
189
The higher the irridance value, the higher the amount of:
photons
190
Procedurable factors that are light-cure variables inlcude: (3)
1. exposure time
2. tip size
3. distance
191
Clinical/Restoration factors that are light-cure variables inlcude: (3)
1. darker shades absorb light
2. smaller particles increase light scatter
3. curing through tooth results in decreased output
192
1. Quartz-tungsten-halogen (QTH)
2. Plasma arc
3. laser
4. light-emitting diodes (LED)
Types of curing units
(1 & 4 are bolded on lecture)
193
Factors that reduce light output:
1. degradation (light reflector, fiber optic bundle, bulb)
2. tip contamination by resin buildup (lower output)
3. sterilization problems (frosting the tip)
4. infection control barriers (need longer curing times)
194
-marginal staining
-increased wear
-disadaptation
-post-operative sensitivity
-enamel microcracks
-release of chemicals
-bulk fracture of the restoration
-secondary caries
-microleakage
These are all problems associated with:
Deficient polymerization
195
~15 microns thick, on the outer layer which facilitates addition & wetting of subsequent layers:
Oxygen inhibited layers
196
Just cured composite may have ___% of the unreacted methacrylate groups to co-polymerize with the newly added material
50%
197
Older restorations that cure over time will not have the ______ groups
This causes the repair strength to be 50% of the original restoration
unreacted methacrylate
198
Important properties of dental composites include: (7)
1. polymerization shrinkage & stress
2. wear resistance
3. marginal infiltration
4. water sorption
5. radiopacity
6. color stability
199
Stress level caused by polymerization shrinkage varies depending on: (2)
1. the type of restoration
2. configurations factor (C-factor)
200
(bonded) / (unbonded surfaces) =
C-factor
201
The higher the C factor=
The higher the stress
202
One advantage to a self-cure composite over light-cure composite is:
