DMS summary - liners & bases Flashcards
1
Q
What is a liner
A
applied in a thin layer over exposed dentine
2
Q
What are the functions of a liner
A
- Dentine sealing
- Pulpal protection
- Thermal insulation
- Stimulation of formation of tertiary dentine
- Can also help to reduce pulpal inflammation
3
Q
What is a base
A
applied in a thick layer on the floor of a cavity
4
Q
What are the functions of a base
A
- Protect pulp by providing thermal insulation & absorbing occlusal forces
- Line out undercuts for indirect restorations
5
Q
What type of calcium hydroxide is used for liners
A
setting calcium hydroxide
6
Q
How does calcium hydroxide come to you?
A
as a base and catalyst
7
Q
What are the constituents of the base in calcium hydroxide liner
A
- CaOH
- zinc oxide (filler)
- zinc stearate (filler)
- platicizer
8
Q
What are the constituents of the catalyst in setting calcium hydroxide liner
A
- Butylene glycol disalicylate - reactive element
- Filler
9
Q
What is the setting reaction for calcium hydroxide liner
A
- Chelation reaction
- Happens between ZnO & butylene glycol disalicylate
10
Q
What are useful properties of calcium hydroxide liner
A
- Stimulates production of tertiary dentine
- Bactericidal (due to high pH)
- Low thermal conductivity
11
Q
What are not so useful properties of CaOH liner
A
- Highly soluble - if there is any leakage it will disappear but also dentine is moist so :/
12
Q
What are uses of CaOh liner
A
- Liner
- direct/indirect pulp capping
13
Q
What is the brand name of CaOh liner
A
dycal
14
Q
How does zinc phosphate cement come to you
A
- powder and liquid
15
Q
What is in the zinc phosphate cement powder
A
- Zinc oxide - reactive ingredient
- Magnesium oxide - gives strength and colour
16
Q
What is in the liquid of zinc phosphate cement
A
- phosphoric acid (about 50%)
- aluminium and zinc oxide - buffer the solution
17
Q
What is the setting reaction for zinc phosphate cement
A
- Initially acid base reaction
- Followed by a hydration reaction
18
Q
What is an important thing to note on the setting reaction of zinc phosphate cement
A
its exothermic
19
Q
What are useful properties of zinc phosphate cement
A
- Solubility is ok (not amazing though)
- Low thermal conductivity
- Quick setting
20
Q
What are not so useful properties of zinc phosphate cement
A
- ts quite acidic when its just been mixed (reduces as it sets) but can cause a bit of pulp irritation
- Shrinkage during setting
- Exothermic reaction
- Brittle
- Not adhesive to tooth
21
Q
What are uses of zinc phosphate cement
A
- A base
- Luting cement
22
Q
What is the brand name of zinc phosphate cement
A
detrey zinc
23
Q
What should you be cautious of when you are using zinc phosphate cement
A
how close you are to the pulp
it starts off acidic + an exothermic reaction so dont want to hurt pulp
24
Q
What is the difference between zinc phosphate cement and zinc polycarboxylate cement
A
- Similar to zinc phosphate but phosphoric acid is replaced by polyacrylic acid allowing it to bond to tooth similarly to GI
25
What are useful properties of zinc polycarboxylate cement
* Bonds to enamel, dentine and alloys (except untreated gold restorations)
* Less irritating to the pulp than zinc phosphate
26
Why is zinc polycarboxylate cement less irritating to the pulp than zinc phosphate
* Its ph returns to neutral quicker
* It has longer chain acids which do not penetrate dentine as easily
27
What are not so useful properties of zinc polycarboxylate cement
* Lower compressive strength than zinc phosphate
* Has a lower modulus (we want a modulus similar to dentine)
28
What are the uses of zinc polycarboxylate cement
* Base
* Luting cement
29
What is the brand name of zinc polycarboxylate cement
* Poly-F Plus (dentsply manufacturer)
30
How does zinc oxide eugenol come to you
powder and liquid
31
What are the constituents of zinc oxide eugenol powder
* Zinc oxide - reactive ingredient
* White resin
* Zinc stearate
* Zinc acetate
32
What are the constituents of zinc oxide eugenol liquid
* Eugenol - active ingredient
* Water & oils
33
What are modifications on ZOE
resin modified ZOE
EBA ZOE
34
What is resin modified ZOE
resin is added to the power and liquid
35
What advantages does resin modified ZOE have
* greater strength and decreased solubility.
* Resin modified ZOE is suitable as a liner.
36
What is EBA ZOE
has ethoxybenzoic acid
37
What are advantages of EBA ZOE
* stronger than the other ZOEs and less soluble
38
What is the setting reaction for ZOE
Acid base reaction + chelation
39
What are useful properties for ZOE
* Low thermal conductivity
* Radiopaque
40
What are not so useful properties for ZOE
* Low strength
* High solubility
* CANT BE USED WITH COMPOSITE
41
Why is ZOE's high solubility not necessarily a negative thing in some circumstances
* it constantly releases eugenol and eugenol has a obtundent (obtundent means ‘lessening pain/irritation’) effect on the pulp
42
What are uses of ZOE
* Base (but can also be used as a liner in very deep cavities)
* Temporary restorations
* Root canal sealer (slow setting)
* Periodontal dressings (fast setting)
* Used in primary RCT as it is resorbable
43
What is the brand name for resin modified ZOE used in GDH
kalzinol / IRM
44
What are the two types of GI
conventional + RMGIC
45
How does conventional GI come
acid and base
46
What are the constituents of the acid in conventional GIC
* Polyacrylic acid
* Tartaric acid (controls setting)
47
What is the composition of the base in conventional GI
* Silica
* Alumina
* Calcium fluoride
* Aluminium fluoride
* Aluminium phosphate
* Sodium fluoride
48
What is the setting reaction for conventional GI
* Acid base reaction with 3 phases - dissolution, gelation, hardening
49
What happens in the dissolution phase (GI setting reaction)
acid reacts with outer layer of glass leaving an unreacted glass core with silica gel on the outside
50
What happens in the gelation phase (GI setting reaction)
calcium cross linking
51
What happens in the hardening phase (GI setting reaction)
aluminium cross linking
52
What are useful properties of conventional GI
* bonds to tooth
* Good thermal expansion
* Fluoride release
* Lower modulus
53
What are not so useful properties of conventional GI
* Not very strong
* Not very hard (worn away easily)
* Higher solubility especially when first placed
54
How does GI bind to tooth
* Binds to tooth via ion exchange (calcium in enamel/dentine) and hydrogen bonding (collagen in dentine)
55
What are uses of conventional GIC
* Base
* Liner
* Temporary restoration
* Restoration
* Fissure sealants
* Luting
56
How does RMGIC come
powder and liquid
57
What is in RMGIC powder
* Fluro-alumino-silicate glass
* Barium glass (for radiopacity)
* Vacuum dried polyacrylic acid
* Potassium persulphate (for redox reaction)
* Ascorbic acid
* Pigments
58
What is in RMGIC liquid
* HEMA
* Polyacrylic acid with pendant methacrylate groups
* Tartaric acid
* Water
* Photoinitiator
59
What is the setting reaction for RMGIC
dual curing & tri curing
60
What is dual curing
* initially get the same reaction as conventional, light activation results in resin matrix being formed while acid base reaction continues within it
61
What is tricuring
* has a redox reaction as well to try encourage sufficient curing where there is insufficient light penetrating
62
What are useful properties of RMGIC
* fluoride release
* command set
* stronger than normal GIC + better aesthetics
63
What are not so useful properties of RMGIC
* Polymerisation contraction
* Reduced strength if it is not light cured properly
* HEMA can be cytotoxic
64
What are uses of RMGIC
* Liner
* Base
* Restoration material
65
What is the brand name of RMGIC
vitrebond
riva light cure (more viscous)
