CSAR Flashcards
1
Q
what can’t an indirect restoration have?
A
undercut
2
Q
4 disadvantages of crown?
A
- destructuve to tooth tissue
- potential for pulp damage
- fail eventually
- expensive
3
Q
what is an inlay?
A
intra-coronal indirect restoration
4
Q
2 types of ceramic crown?
A
Emax + zirconia
5
Q
4 materials crowns can be made from?
A
- all metal
- ceramic
- PFM
- composite
6
Q
can emax or zirconia be etched?
A
emax
7
Q
2 types of cementation method?
A
mechanical - conventional
adhesive - resin cement
8
Q
when an anterior tooth is under load what sort of force acts palatally and buccally?
A
tension palatally
compression buccally
9
Q
what does marginal breakdown of posterior teeth lead to?
A
cuspal flexure = crack
10
Q
3 stages of preparation for crown
A
- occlusal reduction
- axial reduction
- marginal configuration
11
Q
what is the critical area of a tooth to retain tissue?
A
peri-cervical area
12
Q
advantage of adhesive retention?
A
conservative to tooth tissue
13
Q
main contraindication to indirect restoration
A
periodontal disease
14
Q
5 considerations for restoring a tooth with a crown
A
- ability to retain core
- isolation ability
- ferrule necessary to retain indirect restoration
- retention/resistance form
- cold sensitivity
15
Q
how much more preparation on functional cusp?
A
0.5mm more
16
Q
what is retention form
A
prevents removal of restoration along long axis
17
Q
what is resistance form
A
prevent removal of restoration in apical/oblique direction
18
Q
what is minimum height a prep can be
A
~ 3-4mm
19
Q
what is the ideal taper
A
6-12degrees
20
Q
3 reasons margin of crown must be good
A
aesthetics
periodontal health
marginal seal = prevent microleakage
21
Q
3 types of margin design
A
shoulder
chamfer
knife-edge
22
Q
what type of margin for metal?
A
chamfer
23
Q
what type of margin for porcelain?
A
shoulder
24
Q
why should anterior margins be just subgingival?
A
aesthetics
25
what do adhesive restorations require?
enamel all way round tooth
26
what does an onlay require?
enamel all way round the tooth
27
9 steps for crown provision
1. make matrix
2. prepare tooth
3. retraction
4. use matrix to make provisional
5. remove cord after 6 mins
6. working impression
7. jaw reg (if needed)
8. facebow (if needed)
9. cement provisional
28
5 reasons SA articulator may be used
1. multiple restorations
2. increasing VD
3. reorganising occlusion
4. removing occlusal interferences
5. when occlusal stabilisation splint required
29
6 ways to create space for restoration
1. increase OVD
2. dahl concept
3. enameloplasty
4. distalisation of mandible
5. crown lengthening
6. Orthodontics
30
in what position is OVD measures?
ICP
31
definine CR
position of musculoskeletal stability provided by healthy TMJS when the condyles are in their most superior position within the glenoid fossa with the discs correctly interposed
32
how much unprepared axial surface below the prep needs to be recorded in the impression?
0.5mm
33
how does moisture effect impression material?
physical barrier
34
if you were making a crown but couldn't get moisture control because of inflammation from a preexisting overhanging restoration, how would you proceed?
1. prepare + place new restoration
2. wait 3-4weeks
3. prescrive 0.12% chlorhexidine for 2/52
35
2 types of haemostat agents used on retraction cord?
1. vasoconstrictors
| 2. astringents
36
how do astringents work and what is an example?
precipitate proteins on contact with blood, physically obstruct blood vessels
e.g. ferric sulfate, aluminium chloride
37
why does ferric sulphate cause blue/black stain for 1-2 days?
precipitating protein contains iron
38
for adequate thickness of impression material, how wide do you need to horizontally open sulcus?
0.2-0.3mm
39
2 ways of opening up sulcus for impression?
1. surgery
| 2. retraction cord
40
what is the first retraction cord you put in?
compression cord - finest 00 or 000
placed to depth of sulcus
to prevent haemorrhage + GCF
41
what is the second retraction cord you put in?
deflection cord - wide as you can fit, 0 or 1
| half into sulcus
42
how long do you leave retraction cords for?
5-6mins
43
what instruments used to put cords in?
carver or Williamson probe
44
when do you remove deflection cord?
before impression
45
when do you remove compression cord?
after impression
46
what material is used for impression for crown?
light bodied silicone around prep
| heavy bodied around surrounding arch
47
how to critique impression
check finish line + material past it
no critical air blows/drags/voids
sufficient occlusal defila
sulcus captured
48
4 reasons to make provisional restoration?
1. diagnostic
2. pulpal protection - must have marginal seal
3. gingival management - must have marginal fit + contour
4. position stability - must have ICP contact, contact point
49
3 methods for making provisional crown?
1. matrix
2. shell
3. freehand
50
2 material choices for provisional restoration?
1. acrylic e.g. Bosworth trim/snap
| 2. bis-acryl composite e.g. quicktemp, protemp
51
properties of acrylic provisional
```
hand mix
slow set
moderate exotherm + high shrinkage
easy to add to
more flexible
```
52
times you were use acrylic provisional
relining shell provisionals
provisionals around partial dentures
lateraling gingival contour
53
properties of bis-aryl provisional
```
automix - easier
quick set
low exotherm + low shrinkage
harder to add to
brittle/not flexible
```
54
when would you use bis-acryl provisional
simple matrix provisionals
55
how do you stop provisional bonding to composite core?
glycerine/vaseline
56
2 types of temporary cements
1. zinc oxide cement - temp bond
| 2. zinc polycarboxylate cement - polyF, durelon
57
when do you use zinc oxide and when to use zinc polycarboxylate to cement provisional restorations?
zinc oxide = if satisfactory resistance/retention
| zinc polycarboxylate = when resistance/retention lacking
58
what type of temp bond is used if composite core?
temp bond non eugenol
59
types of shell technique provisional crowns?
standard crown forms - polycarbonate, aluminium, stainless steel
lab made crowns - acrylic, composite
60
method for placing shell technique provisional crown
1. pick crown
2. trim if necessary
3. make hole interproximal to help achieve contact point
4. reline with acrylic temp material
5. fill shell with acrylic
6. seat
7. remove in dough stage
61
if prep is occlusal stable and doesn't need provisional how would you dress it?
```
fluoride varnish (? - can integrate into hydroxyapatite + change surface)
zinc phosphate covering
```
62
what is index shrink-wrap?
putty made from wax up, putty filled with bis-acryl + cured straight to teeth
63
how would you temporise an occlusaly unstable resin bonded bridge prep limited to enamel?
composite to opposing tooth
64
how would you temporise veneer prep that extends through contact points?
composite cured to prep
65
how would you temporise occlusally stable resin bonded bridge prep that extends into dentine + sensitive?
zinc phosphate or zinc carboxylate covering
66
2 techniques for labs making indirect restorations
1. lost wax technique
| 2. hand layered
67
advantages and disadvantages of bi layered restorations
```
+ better aesthetics
+ combine best 2 qualities of materials
- postnatal weak points at interfaces
-risk of chipping/fracture
- need for greater prep
```
68
advantages and disadvantages of monolithic restorations
```
+ stronger
+ more conservative
+ cheaper
- limited aesthetics
- only character with stains
```
69
occlusal + marginal reduction for metal crown?
1-1.5mm
| 0.1mm chamfer
70
occlusal + marginal reduction for porcelain + metal areas of PFM
2-2.5mm
| 1-1.2mm
71
what technique can be used to reduce margin prep in posterior teeth?
high strength metal collar
72
what is the umbrella effect?
metal ceramic margin creates blueish appearance at margin
overcome by extending porcelain palatally
73
what type of restoration is zirconia?
conventional
74
difference between traditional zirconia and new high translucency zirconia
old - bilayered as opaque, stronger, hard to adjust
high translucency = monolithic or bilayer, weaker, easier to adjust
75
what type of zirconia is used as collars?
bilayered high translucency
76
does bilayering lead to better or worse aesthetics for zirconia?
better
77
what is Emax?
lithium dislocate
etch able glass ceramic
can be cast or CADCAM
78
is Emax normally monolithic or bilayered?
posterior teeth = normally monolithic as stronger
| anterior teeth = make monolithic + then cut back and layer with feldspathic porcelain
79
2 types of etchable ceramics
Emax
| feldspathic porcelain
80
advantages and disadvantages of indirect composite
```
+ better conversion of monomer than normal composite
+ easier to adjust + repair
+ cheaper
+ thinner section
- more flexible so weaker than emax
- problems with debond
```
81
how are precious metal restorations made?
cast
82
how are non-precious metal restorations made?
cast of CADCAM
83
how are lithium disilicate restorations made?
cast or CADCAM
84
how are zirconia restorations made?
CADCAM
85
how are feldspathic poreclain restorations made?
hand layered or CADCAM
86
how are resin based restorations made?
hand layered or CADCAM
87
how does translucency of material affect aesthetics?
the more translucent = more potential
when core not favourable - must leave room for technicians
88
4 types of passive cements
1. zinc phosphate
2. zinc carboxylate
3. GIC
4. RMGIC
89
how do strength and translucency relate to each other?
as strength increases, become less translucent
90
order of crown materials from most strong (most opaque) to least strong (most translucent)
1. metal
2. zirconia
3. high translucency zirconia
4. emax
5. feldspathic porcelain
91
advantages and disadvantages of adhesive indirect restorations
+ more conservative
+ less reliant on resisitance/retention form
+ advantages when limited crown height
- harder to temporise
- need to isolate
- bond is unpredictable
- cementation much more technique sensitive
92
what must you check on patient before trying in crown?
occlusion - find holding contacts with shim stock
check dynamic for reference
93
if bonding precious metal, why must you always use primer?
precious metals don't have oxide layer to easily bond to
| sulphur group f VBATDT in alloy proimer bonds to metal
94
what is a cantilever bridge?
attached on one side
95
3 types of conventional bridge?
cantilever, fixed-moveable, fixed-fixed
| use crowns as retainers
96
2 types of adhesive/resing bonded bridge?
cantilever, fixed-fixed
97
approx longevity of conventional + resin bonded bridges?
conventional ~10yrs - take abutment with
| resin bonded ~5yrs - abutment spared
98
if using a fixed-fixed conventional, what must both abutment teeth have? how can this be overcome?
common path of insertion
use fixed-moveable
99
structure of a fixed movable conventional bridge?
major retainer - rigid connector - Pontic - moveable connector - minor retainer
100
advantages + disadvantages of adhesive bridge?
```
+ conservative
+ impression easier
+ failure less destructive
- don't last as long
- cannot shape abutment teeth
- can discolour if thin
- need enamel
- technique sensitive
```
101
what is antes law?
total periodontal membrane of abutment teeth must equal or excess that of tooth to be replaced
now evidence to suggest as long as good perio + maintenance more extensive bridges can be successful
102
what should occlusion of a Pontic be?
contact in ICP but not In excursion
103
where are fixed-fixed and cantilever preferred and why?
```
posterior = vertical forces = fixed-fixed
anterior = lateral forces = cantilever
```
104
what is the optimum and minimum crown:root ration for abutment teeth?
optimum 2:3
| minimum 1:1
105
how does a big span effect the Pontic?
bigger the span = more bending/flexion of Pontic
+ increased load of abutment teeth
may lead to fracture, debonding of one retainer
106
what is minimum thickness of RBB retainer to prevent flexion?
0.7mm
107
2 features of anterior RBB prep
cingulum rest
| finish line
108
3 features of posterior RBB prep
rest seat
guide plane - remove bulbosity to help with seating
finish line
109
what should existing restorations be replaced with (if not already) before RBB?
composite
110
3 types of periodontitis
1. marginal
2. apical
3. both - perio/endo
111
to have apical perio what must the pulp be?
non-vital
112
how to treat perio-eondo lesion with communication?
endo first
| perio after 1 month to allow some bony infill
113
what type of cells are responsible for resorption of dentoalveolar hard tissues?
giant cells - derived from mononuclear phagocytes
114
how long does transient resorption happen for and why?
2-3weeks
| no constant stimulation of giant cells
115
what stimulates giant cells?
pressure + infection
116
3 systemic disorders linked with root resorption?
1. hypo/hyperparathyroidism
2. pagets disease
3. benign/malignant tumours - causes pressure
117
how is resorption prevented after RSI?
epithelium migration
118
what is cervical resorption?
type of progressive external inflammatory resorption
| lesions begin in cervical region + communication with mouth
119
what is richwil crown remover?
toffee like substance, chewed to remove crown
120
what is a masserran kit?
removes threaded post in anticlockwise direction
121
how do you remove gutta percha?
size 10 file + sodium hypochlorite
| my need solvent - chloroform, eucalyptus + orange oils
