reading stuff Flashcards
(173 cards)
1
Q
What is the best consideration for a tooth significantly weakened by extensive defects, especially in areas of heavy occlusal function where esthetics are a primary concern and why?
A
Ceramic onlays, crown, PFM crown
Bonds to tooth so good
2
Q
What determines the lifespan of an esthetic restoration?
A
Nature and extent of initial caries Treatment procedure restorative materials and technique used Operator skill Patient factors (oral hygiene, occlusion, caries risk, adverse habits)
3
Q
common reasons for failure of composites
A
Trauma
Improper prep
inferior matierals
Improper use
4
Q
True or False: Composites can be used in almost any tooth surface or any kind of restorative procedure.
A
True
5
Q
True or False: The ability to bond relatively strong material of composite to tooth structure (enamel and dentin) results in a restored tooth that is both well sealed and possibly regains a portion of its strength.
A
True
6
Q
what kind of restoration is a fused (baked) Feldspathic porcelain inlay
A
Indirect ceramic restoration
7
Q
benifit of CAD/CAM chairside ceramic restoration
A
eliminates need for impressions and temporary restoations
no ned for lab procedures and costs
less appointments
8
Q
Types of Esthetic restorative materials
A
Ceramic inlays and onlys
Silicate Cement
Acrylic resin
Composite
9
Q
what was the first translucent restorative material
A
Silicate cement
10
Q
how long does silicate cement last in anterior teeth restorations
A
4-10 years
11
Q
what lead to the belief that enamel adjacent to silicate cement was more resistant to caries
A
High fluoide content and solubility
12
Q
what is the contempory versions of Silicate Cement
A
GIs (less soluble though)
13
Q
how is Silicate cement made
A
Powder (acid-soluble glass)
Liquid (Phosphoric acid, water, and buffering agent)
14
Q
How does Acrylic Resin cure
A
Self curing
15
Q
problem with curing acrylic resin
A
Poor activator systems
high polymerization shrinkage
high linear coefficent of thermal expansions
lack of wear resistance (leakge, pulp injury, recurrent carries, color change, excessive wear)
16
Q
when is acrylic resin not indicated
A
High stress areas (low strength and flowing under load)
17
Q
when is acrylic resin used
A
temporary restorations esthetic veneer on facial of class 2 and IV
18
Q
what is a composite
A
Polymeric resin matrix with inorganic fillers
19
Q
roll of inorganic fillers in composite
A
Enhance physical properties (strength and reduce thermal expansion)
20
Q
what is done to increase bond strength between organic matrix and inorganic filer in composites for increased mech properites
A
coat filler w/ silane coupling agent (increase strength, solubility and water absorption)
21
Q
Macrofill composites
A
Convensional composites with 75-80% inorganic filler (8 micrometers) by weight
22
Q
Characteristics of macrofill composites
A
rough surface texture
easily stained
resin matrix wears faster than filler
23
Q
what makes up microfill compoistes
A
35-60% inorganic filler(.01-.04 micrometers of colloidal silica parties) by weight
24
Q
use of macrofill today
A
Not used
25
properties of microfill composites
smoother (less stain)
less filler (inferior physical and mech properties)
highly wear resistant
low modulus of elasticity (flexes with the tooth)
26
what is hyride composites
75-80% inorganic filler by weight (microfiller and smaller filler particles)
27
why was hybrid composites made
Combine physical and mech of macro and smooth surface of micro
28
benifit of nanofill composite
Highly polishable (.005-.01 micrometer)
29
popular composite types
Nanofill and nanohybrid
30
why was packable composite made
easier restoration of proximal contact( increased viscosity makes marginal adaptation difficult
similar to handle like amalgam
(never reached these goals
31
where should floable composite never be placed
high occlusal or proximal stress (low filler so weak)
32
what acid is used with conventional GI
Polyacrylic acid (less soluble)
33
what is good for root surface acries
Conventional GI
34
when to use Conventional GI
in patients with high caries activity
non occlusal
permanent cementation of crowns
35
why was RMGI made
improve physical properrties of GI
36
properties of RMGI
resin makes it light curring also autocurring
easier to use
better strenth, resistance, and esthetics
37
when is RMGI usually used
```
Class V in adult with high risk
class I and II for primary teeth no requiring long term service
```
38
what are compomers
composites with some GI components
39
LInear Coefficient of thermal expansion
Rate of dimensional change of material per unit change in temperature
40
How does Composite Linear coeffieicnt of thermal expansion differ from a tooth
3x tooth LCTE
41
How to decrease the negative effects of LCTE
bond composite to etched tooth surfcace
42
water sorptions
amount of H2O material absorbed over time
43
how to decreased water sorptions
increase filler
44
what has better wear resistance composite or amalgam
Amalgam
45
where is smoothness needed for composite
close to gingival tissues for heath
46
what has the smoothest surface
Microfill (nanohybrid and nanofill also good)
47
why is radiopacity important
so recurrent caries around or under restoration can be seen easily on the radiograph
48
modulus of elasticity
stiffness (higher means more stiff
49
pros and cons of low modulus of elastisity
allows bending of restoration with tooth, protecting interface
lower mech and physical properites
50
solubility of composites
like none
51
how to minimize effects of polymerization shrinkage
load in steps
using adhesives
using RMGI before composite to reduce microleakage and gap fomation
52
when is shrinkage of composites a problem
at the root surface (force of polymerization >initial bond)
53
configuartion factor
ratio o bonding surface to undbonded surfaces
54
greater configuration factor means
greater potentional for bond disruption via polymerization
55
pros and cons of self cured composites
greater risk for air inclusions
working time restricted
color instability
direction of polymerization generally centralized for better marginal adpatation and prevention of microleaks
56
pros and cons of Light cure
increased working time
less finishing time
better color stability (better bonding, improved properties
more success and economical
57
INdications of composite
```
CLASS i-vi
Core buildups
sealants and preventative rstorations
parital and full veneers
tooth contour mods
diastema closure
cements
temporaries
Perio splinting
```
58
contraindications of composites
bad isolations
all the occlusaion on the restorative material
restorations with extensions on the root surface
59
advantage of composites
```
esthetics
conservative
less complex preps
insulating to heat
bond to tooth
repairable
```
60
disadvantage of composites
```
gap formation on the root
more costly and time consuming
technique sensitive
isolation
LCTE
```
61
True or False: If a void is detected immediately after insertion of composite but before contouring, more composite can be added directly to void area
True: must re-etch though
62
cause and solution of white line adjacent to halo
trama during contouring or finishing, inadequat ethcin, excessive polymerizations
re-etch, prime and bond, being ldightly, leaving a monitor for leaks
63
where is the exchange zone
over the chest under the chin
64
should the operator move eyes during tool exchange
No
65
Goal of isolation
Moisuter control
retraction and access
harm prevention (spray from handpiece can alarm patient)
66
benifits of the rubber dam
```
Dry, clean field
acess and visibility
improved properties of dntal materials
protects patients and operator
efficiency (patient doesn't talk or get in the way)
```
67
when to not use a rubber dam
teeth have no erupted sufficiently
3rd molars
badly malpositioned teeth
can't breath through nose
68
thin vs thick rubber dams
```
Thin: easier to place
thick: better retracting gingiva and more tear resistant (class V)
```
69
what side of the rubber dam should be used
the dull side (less reflective)
70
what should be done after the rubber dam is removed
massage gingiva to increase blood flow
71
how should retainers be placed on children
More gingivally due to short clinical crown
72
what retainers are used in priamry and young permant teeth
27: primary
w14: perminant
73
what drug is rairly used to decrease salivary flow when not using a rubber dam
Atropine
74
characteristics of air rotary power cutting instruments
head is smaller, weigh less, have more vibration
75
characteristics of electric rotary power cutting instruments
cut with higher torque and little stalling, high-precision cutting, higher initial expense and the weight and balance of it will confuse older clinicians, quieter and smoother cutting
76
low speed handpiece
12,000 rpm ( for cleaning, caries, finishing and polishing
77
high speed handpiece
200,000 rpm (preps and removal of old restoration
78
the part of the handpiece that goes into the rotary instrument
Shank
79
the cutting part
Head
80
negative rake angles
rake face ahead of radius of bur
81
possitive rake angles r
rake face behind the radius of the bur
82
rake angle
the angle between the rake face and the axis of bur
83
edge angle
the angle between the rake face and the clearnace face
84
clerance angle
the angle between the clearance face and the cut surface
85
the rake face
the face of the bur that does the cutting
86
the clearance face
clears chips (right after the rake face)
87
roll of Silicate glass particles in a composite
mech reinforement
| light transmission and scattering (esthetics)
88
roll of acrylic in composoites
fluid and moldable
89
roll of the matrix phase of a composite
adapt to tooth prep
| penetrate into micromech spaces of the etched enamel or dentin
90
what are bonding systemes made of
unfilled acrylic monomer mixes
91
what does a sbonding system do
fomrs a 1-5 micrometer film on etched surfaces to interlock mechanically to seal walls and co polymerizes with compsoite restorative material that fills the tooth prep
92
what is unfill sealance
unfilled acrylics (2% filler modified sealants)
93
pros and cons of high filler content
high filler improves all properties but fluidity
94
75% silica by weight is how much by volume
50%
95
for hybrid composites how are they named
named based on the largest filler in them
96
when is a composite homogeneous
when it consists of filler and uncured matrix
97
when is a composite heterogeneous
also has precurred composite and unusual filler
98
when is a composite modified
has novel filler modifications
99
how do heterogeneous microfills work
precured particles chemically bond to the new material
100
how is collloidal silica made
chemically precipitated from a liquid solution as amorphorus particles
101
how is pyrogenic silica made
precipitated from gaseous amorphous microfillers
102
what happens to light output as you decrease the fiber optic tip size
the light output decreases
103
how much will the pulp have to increase in temp for ti to die
5-8 degrees celcius
104
what causes curing light to scatter
filler particles
105
what absorbs more light, darker or lighter colorants
darker absorbs more
106
how much composite normal goes from monomer to polymer
55-65%
107
what leads to higher stress light composites or autocurred
light (higher energy curing light makes the problem bigger in addition to higher filling)
108
when would you want low and high elastic modulus
low: more retention
high: MOD to prevent tooth bending
109
CFA wear
wear due to food and not teeth usually found on small occlusal preps
110
what is CFA wear resistance related to
filler spacing not composite mech strength(microprotection)
111
Microprotection
when filler is close together so it protects the resin from wearing
112
what does color matching consist of
current colors and colors over the course of tie
113
should the tooth be wet or sry when color matching
wet (if dry will look too wet)
114
what type of material is more likely to yellow
Ante-rior restorative materials with high matrix contents that are self cured
115
what proceedure makes color matching difficult
bleaching (wait till tratment is done)
116
How can one make the difference between enamel and composite color less noticable
Bevel the edge
117
where do secondary caries occur most often
proximal and cervical margins
118
what is the biggest concern for posterior composites
posterior wear
119
cytotoxicty of unpolymerized materials
concern for post opperative sensitivty
but poorly solube in water, and polymerized intoa bound state
low amount does escapte
120
what are glass ionomers
materials consisting of ion-cross-linked polymer matricies surrounding glass-reinforcing filler particles
121
what are glass ionomers made of
aluminosilicate powder from silicates
| polyacrylic acid liquid of polycarbs
122
water of glass ionomers and composites
GI: philic
Composites: phobic
123
pros and cons of ceramic metals (cermet) mixtures
much stronger than normal GI, but poor esthetics and not modified
124
uses of cermets
as cores
125
what is atrauamic restorative treatment
done when no professional available. remove caries without using instruments and then place GI in hole and have the person bite on it to make it the right shape
126
How does GI hold into the prep
Chem and mechanical means (good mech is better than good chem)
127
recharging of GI
when you place high levels of fluoride on the tooth and it goes back into the GI
128
Adhesion
the state in which 2 surfaces are held together by interfacial forces which may consist of valence and interlocking forces
129
mechanical adhesion
interlocking with irregularities in the surface
130
adsorption adhesion
chemical bonding between adhesive and the adhered (primary: ionic and covalent) (secondary: h bonds, dipole, van der waals)
131
Diffusion adhesion
interlocking between mobile moleulces
132
electrostatic adhesion
double layer of electrical at the interface of a metal and polymer
133
how are resins bound to toooth
Mech
adsoprtion
Diffusion
134
what is needed for good adhesion
glose contact
| surface tension of adhesive lower than that of substrate
135
the major problems for bonding resins
resins shrink so adhesives must provide a strong initial bond to resist stresses of shrinkage
136
type I enamel etching pattern
Dissolution of prism cores without dissolution of prism peripheries
137
type II enamel etching pattern
dissolution of prism peripheries without dissolution of prism cores
138
type III enamel etching pattern
has patterns without prism morphology
139
what makes up enamel etchants
Phosphoic acid at 37% (30-40%)
140
bond strength of enamel etchants
20-50 megapascals
141
what is harder to bond
dentin or enamel
142
what in the smear layer allows for diffusion of the dentinal fluid
submicron porosity
143
what is the configuration factor
ratio of number of composite bonded surfaces to unbonded surfaces
144
what is water absorption by the resin related to
resin content
145
3 step etch steps
1. Phosphoric acid etchant that is rinsed off
2. A primer containing reactive hydrophilic monomers in alcohol, ethanol, acetone, or water
3. Unfilled or filled resin bonding agent (adhesive) that contains hydrophobic monomers (Bis GMA) and hydrophilic molecules (HEMA)
146
purpose of primer in 3 step etch
increase surface tension of dentin
147
what happens when primer and bounding resin are applied to etched dentin
they penetrate the intertubular dentin and form and interdiffusion zone (hybrid layer) and polymerize the open tubules to form resin tags
148
2 step self etch
uses self etch primers containing phosphonated resin molecules that etch and prime dentin and enamel
no rinse
149
what happens to the resin tags in 2 step etch
smear plugs in the resin tags for less post op sensitivty
150
etching efficiency of two step etch
do not etch as well as enamel
151
what is in1 step self-etch adhesives
contain uncured ionic monomers that contact the compsote material directly
152
how do 1 step eself-etch adhesivess work
semi-permeable membranes, resulting in hydrolytic degradation
153
roll of water in self-etch adhesives
solubilize ca and p ions that form from the interaction of the monomers with dentin and enamel
154
patial removal of what protein may enhance remineralization
phosphoproteins
155
collagen not encased in resin can do what which is bad
vulnerable to degradation by matrix metalloproteins
156
microleakage
passage of bacteria and toxins between restoration and tooth walls
157
when does microleakage matter
pulpal irritiation by bacteria not chemical toxicity of restorative material
158
nanoleakage
small porosities in the hybrid layer or at the transition between the hybrid layer and the mineralized dentin for minuscule particles
159
what type of dentin is more resistant to acid etching
sclerotic dentin
160
what type of composites have a low elastic modulus
Microfilled composites
161
what area of the tooth is most hypersensitive
Cervical area
162
what does GLUMA work
reduced dentin sensitivty through a protein denaturation process
163
what must be done for cermanic and zirconia restorations
etched with HF acid for 1-2 minutes to create retentive microporosities
then rinsed
coupling agent applied
primer used with phosphonic acid monomer or carboxylate monomer to improve resin bonding
164
when is it best to place selants
in perminant teeth of children
165
how long to etch for a sealant
15-30 second
166
do carbide or diamond make a thicker smear layer
diamond
167
how far is needed to be left in the marginal ridge to not make a proximal box
1.5mm
168
when to use a RMGI base or CaOH liner
between .5-1.5 RDT use RMGI
| less than .5 mm CaOH then RMGI base
169
stress in relation to C factor
higher stress from higher c factor: more walls bound
170
what can be added to reduce the effects of polymerization shrinkage
RMGI liner or flable composite due to favorable elastic modulus
171
the sandwich technique
when composite is placed over RMGI
172
advantage of the composite technique
RMGI binds to dentin without opening tubules (reduced sensitivity)
RMGI released fluoride
favorable elastic mdoulus
173
what surface does composite not bind to well
the root surface (dentin)
