Lec 1/5 ACC restorations and ceramic materials I Flashcards
1
Q
Indications for full coverage resto:
A
extensive coronal damage, max R/R form needed, short crown, axially tilted teeth, restore endo treated teeth, parafunctional habits
2
Q
Adv of ACC:
A
esthetic, excellent translucency (sim to tooth), good tissue response (biocompatible), lack of reinforcement by a metal substructure permits more conservative reduction of facial surface
3
Q
Disadv of ACC:
A
proper prep design is critical to get mechanical success
4
Q
Contraindications, ACC:
A
more conservative restoration can be used, not possible to provide adequate support or an even shoulder width of at least 1mm circumferentially
5
Q
Slope of ACC should be:
A
NONE! 90’ modified shoulder
6
Q
Reductions for CI ACC:
A
1.5mm incisal, 1mm modified shoulder all around, 1.5mm axial reduction
7
Q
Benefit of proper marginal design:
A
good stress distribution
8
Q
What does occ reduction for ACC depend on?
A
type of ceramic, monolithic, layered, location of resto
9
Q
General occ reduction for ACC:
A
1.5mm - 2mm
10
Q
Type of margin for ACC:
A
butt joint
11
Q
All ceramics have a glass and a crystalline phase except:
A
polycrystalline
12
Q
What is the glass phase of ceramics?
A
Silica, mostly
13
Q
Crystalline phase ceramics:
A
Leucite, LIDi, Alumina, Magnesia, Zirconia
14
Q
2 polycrystalline ceramics:
A
Alumina, Zirconia
15
Q
What are ceramic metals based on?
A
Amt of crystalline phase, fabrication technique
16
Q
As this inc, flexural strength inc:
A
amt of crystalline
17
Q
Type of Leucite that is between Feldspathic and LiDi in terms of flexural strength:
A
pressed
18
Q
TF? Translucency inc, as flexural strength inc.
A
F.
19
Q
TF? Translucency inc, as crystalline inc.
A
F.
20
Q
Ceramics based on crystalline phase:
A
pred glass, particle-filled, polycrystalline
21
Q
5 fabrication techniques for ceramics:
A
Conventional Powder/ Slurry Castable, Pressable, Slip-Casting, Machinable
22
Q
Conventional Powder/ Slurry Ceramics are used mainly as:
A
Veneers, porcelain jacket crown
23
Q
Material for PJC:
A
Feldspathic or w aluminous core
24
Q
Disad v of PJC:
A
brittle, easily fractured, poor marginal adaptation,
25
PJC developed to improve strength of earlier PJCs:
PJC w alumina reinforced core
26
How did the 50% inc in alumina crystals in the feldspathic core strengthen the PJC?
interruption of crack propogation
27
Steps to hand fabricate PJC:
platinum foil matrix, apply alumina reinforced ceramic, sinter, condense feldspathic porcelain, sinter
28
How are castable glass ceramics different than conventional Powder/ Slurry:
Props closer to glass, very different construction, "ceramming" process is unique
29
Tech to make castable glass ceramic
centrifugal casting, only porcelain crown made this way
30
Steps to making a castable ceramic crown:
invest and burn out wax up, heat ceramic ingot to 1350C, cast using centrifuge, recover glass casting by sandblasting, cut sprues away, ceram, surface stained or layered w layered porcelain
31
What is ceramming?
heat tx process, strengthens glass, microscopic crystals of mica are formed that strengthen glass and red transparency, more opaque, less glass like
32
Castable glass ceramics and conventional Powder/ Slurry can be used for these restoration types:
none
33
Pressable ceramics:
Leucite or LiDi based
34
TF? Leucite based pressable ceramics can be monolith or layered, whereas LiDi based pressable ceramic can only be monolithic.
F both can be either
35
TF? All ACC's have superior esthetics than MCCs.
F. some don't, Zirconia doesn't have good translucency
36
zirconia is categorized as ceramic but is actually:
metal alloy
37
TF? Zirconia has reduced strength compared to MCC.
F. metal alloy
38
TF? MCC has higher fracture strength that zirconia.
F
39
Lingual red (not finishline) for a lingual metal crown:
1mm
40
TF? ACC has less flexural strength than CCC.
T
41
Which is more forgivable under forces, LiDi or MCC?
MCC bc of metal substructure
42
Margin width needed for LiDi:
1mm
43
Margin width needed for zirconia;
0.5mm -1mm
44
Core of Alumina or zirconia is coated w:
feldspathic
45
TF? Both LiDi + zirconia can be monolithic.
T
46
What varies bw all ceramic except polycrystalline, glass phase or crystalline phase?
crystalline phase
47
Why is it called predominantly glass phase?
there is more glass phase in the material than crystalline phase
48
Particle-Filled Glass Ceramics are mostly glass phase or crystalline phase?
crystalline
49
Polycrystalline ceramics, mostly glass phase or crystalline phase?
ALL crystalline
50
Does flexural strength inc or dec as you go from primarily glass to polycrystalline?
inc
51
How is Feldspathic categorized based on amt of crystalline phase?
predominantly glass
52
How is Leucite categorized based on amt of crystalline phase?
low-filled, particle-filled glass ceramic
53
How is translucency affected from predominantly glass to crystalline?
dec
54
What happens to light if the material is not transparent?
absorbed or reflected
55
TF? Every ceramic has a different feldpatic layer, but always feldspatic
T
56
Castable glass ceramics, esthetic?
t
57
Castable glass, prone to fracture?
yes
58
3 steps to castable ceramics:
centrifuge (glassy resto), sintering (aka ceramming), staining
59
What is the glass phase of both Leucite and LiDi?
silica
60
What is the optimal pressable ceramic?
Leucite
61
flexural strength lithium disilicate vs. leucite based
350, 130-135
62
Leucite based materials on the market:
IPS Empress Esthetic
63
LiDi materials:
IPS Empress II, IPS E.max
64
This material requires a special oven for sintering:
LiDi
65
Indications for Leucite based:
anterior crowns, veneers, in-onlays
66
Lithium disilicate based indications:
Ant/pos crowns, veneers, in-onlays, 3-unit Ant FDP (not enough flexural strength for pos)
67
% volume of alumina in In-Ceram Alumina:
90%
68
Composition of In-Ceram Spinnel:
Magnesia, Alumina
69
Composition of In-Ceram Zirconia:
67% Alumina, 33% Stabilized zirconia
70
Benefit of In-Ceram materials:
high strength core and layering ceramic
71
Tech that must be used for Slip--Casting (not used in U.S.)
layering
72
Technique to make In-Ceram crowns:
Slip Casting Technique
73
How to make monolithic slip casting ceramic:
can't, only layered
74
Indications for In-Ceram Spinnel:
Ant Crown
75
Indications for In-Ceram Alumina:
Ant/Pos crown, Ant FDP
76
Indications for In-Ceram Zirconia:
pos crown, ant/pos FDP
77
Can machinable ceramics be either monolithic or layered?
yes
78
TF? Both In-Ceram Alumina and In-Ceram Zirconia can be used monolithically.
F. In-Ceram, only layered
79
Leucite and LiDi are machined in this phase:
green phase, not fully sintered, crystals not grown to full extent, still machinable
80
Lower incidence of complications, ACC or conventional single crown:
ACC
81
Most common complications of ACCs:
crown fracture (7%), loss of retention, and need for endo (1%)
82
TF? All ceramics area viable option for laminate veneers, intracoronal restos, full coverage restos
T
83
TF? The 5y survival rate of In-Ceram Spinnel and In-Ceram Alumina are both lower than that of MCC.
F. same
84
Problem with Zirconia veneer:
chipping
85
Use these to adjust ACC crowns:
blue, pink, green polishing disk/ cone
86
Roughest to smoothest for the extraoral polishers for ACCs:
blue pink green
87
Prefer to cut from tooth or crown if crown doesn't fit
tooth, to not create flaws in ceramic
88
If you must cut down crown use this:
red striped diamond bur with lots of water
89
The core materials used for layering crowns are both what type of ceramic?
polycrystalline
90
The only predominantly glass ceramic:
aluminum oxide
91
Air abrasion is aka:
Micro-etch
92
Benefit of silica coated alumina over alumina for air abrading:
allows good bonding to the silica
93
Predominantly glass materials are derived from:
feldspar minerals, silicon and aluminum oxides
94
How are predominantly glass materials used?
veneering material over metal or ceramic coping and frameworks, PJC, in-onlays, porcelain veneers
95
Props of predominantly glass ceramic:
highly esthetic, biocompatible, resistant to abrasion and compressive forces, low mech strength in comparison w other ceramic types, must be cemented adhesively to inc resistance to fracture
96
Delivery of predominantly glass resto:
must use adhesive system, followed by application of a resin cement
97
Type of material, IPS Empress Esthetic:
Leucite
98
Prop of low filled particle filled glass ceramics:
low strength compared to other filled glass materials
99
TF? Particle filled glass ceramics must be cemented adhesively.
T. must use adhesive system, followed by application of a resin cement
100
Ex of a high-filled particle-filled glass ceramic:
IPS e.max Press (LiDi)
101
What are particle-filled glass ceramics reinforced w?
LiDi
102
TF? LiDi must be cemented adhesively for FCC.
F. either (conventionally or adhesively according to prep design)
103
How is conventional cementing carried out?
w conventional luting agents such as RMGI cements wo need for intermediate agents
104
How to increase retention for short clinical crowns?
cement adhesively
105
TF? Partial coverage particle-filled glass restos such as in-onlays and porcelain veneer restorations require adhesive cementation.
T
106
These are densely sintered aluminum oxide or zirconium oxide materials:
Polycrystalline ceramics
107
TF? There is no glass in Polycrystalline ceramics:
T
108
TF? Polycrystalline ceramics must always be cemented conventionally.
F. most of the time, but not always
109
How to inc the bonding strength of resin cements w Polycrystalline ceramics:
air abrasion w aluminum oxide or silica coated alumina oxide followed by adhesive promoting agent
110
How to enhance the bond of resin-based luting agents:
treat zirconium oxide restos w a combo of tribochemical silica and MDP or using a primer based on phosphate and carboxylate functional monomers or a primer combination of MDP and a metal primer
