Cementation of adhesive restorations Flashcards
What is the first stage of RRB fit?
try in mouth to assess:
- pontic
- fit of metal retainer
- occlusion
once you have tried the bridge in, what is the next stage?
decontamination and removal of any glycoproteins and mucopolysaccharides from the fit surface
prepare the fit surface by sandblasting with 50mincrons alumina particles
How shoul dyou prepare the tooth?
using an oil and fluoride free paste
What are the stages of cementation using panavia?
- Prepare tooth
- if precious metal alloy, apply alloy primer to fit surface of metal
- etch enamel with 40% phorphorc acid for 10 seconds and wash for 20 seconds
- apply acidic A and B ED primer to enamel
- air dry for 30 seconds
What is the purpose of the ED primer?
it begins the set of the cement
How is the resin lute activated?
chemically
light
2 ways
How must the resin lute set?
in the abscence of oxygen
What does the paste A resin lute cement have?
MDP: 10-methacryloxydecyl dihydrogen phosphate Hydrophobic aromatic dimethacrylate hydrophpbic aliphatic dimthacrylate hydrophilic aliphatid dimethacrylate sialanted silica filler sialanted collloidal silica camphoroquinone catalysts initiatiors
What does the resin lute paste B have?
Hydrophibic aromatic dimethacrylate hydrophobic aliphatic dimethacrylate hydrophilic aliphatic dimethacrylate silanated barium glass filler catalysts accelerators pigments sodi fluoride
How lnog do you mix each paste a and B togther for?
20 seconds
T/F Panavia provides a better bond to enamel than tp dentine? Why
T
because panavia bonds to the phosphate ions and enamel has more phosphate ions than dentine
How can you allow panavia to set?
if allowing hr margins to chemically cure then apply oxyguard to margins and leave for 3 mins and resin will set anaerobically
if light cuuring then 20 s per surface each margin
Should you polish the cement immediatly?
no
this will distub the rest of the bond forming
What can we use to cement porcelain and compossite veneers?
Esthetic cement
WHat are the advantages of esthetic cement?
avaibale in five ranges
comes with a try in gel in all the shades
light cured or dual cured
lutes ceramic and composite restorations
How do you prepare the surface of the veneer before cementing?
apply K etchant gel
40% phosphoroc acid
5 seconds
what should you apply to the veneer surface once it has ben etched?
silane which should then be lightly air dried
What does the silane contain?
gamma methacyloxy propyl tri methoxy silane
and
MDP resin
How do you prepare the tooth for esthetic cement?
apply 40% phosphoric acid to tooth for 10 seconds
and then place the ED primer (two bottles which have been mixed) on to the tooth for 30 seconds and then air dry
What does liquid A of the ED primer contain?
HEMA
MDP
water
accelorator
What does liquid B of the ED primer contain?
Methacrylate monomer
water
initiator
accelorator
What is the purpose of MDP resin?
Enables resin to etch and penetrate and create a chemical bond wit calcium ion and HAP
What does the clearfil esthetic lutin cement contain?
Paste A Paste B
Bis GMA Bis GMA
TEGMA TEGMA
MDP MDP
silanated glass filler silanated glass filler
colloidal silica colloidal silica
benzoyl peroxide
camphoroquinone
How long should you light cure the esthetic cement?
40 seconds
What can pa avian be used for?
Composite
Silicate ceramic
Metal oxide ceramics eg zirconia
Metal alloys inlcuding amalgam
What is the structure of MDP?
- Polymerisable moiety MDP end
- Hydrophobic section
- Hydrophilic moiety with phosphate group
Which part of the MDP does most of the bonding tot enamel and dentine?
Hydrophilic end group since it dissociates in water and releases Hydrongen ions which etch and the remaining neg charge molecule forms the bond
How does the MDP bond to HAP?
3 methods
- Ionic bond: between one or two oxygen groups in MDP to Ca in HAP
- Covalent bond from one O to the P in in HAP
- Multilayered of MDP forming on HAP via the polymerisable layer end where there is layer of calcium and HAP
What are the purposes of the fillers in panavia?
To add radiopacities
What is the difference of panavia 21 and panavia f2?
It contains Camphoroquinone and sodium fluoride for F release as well as all the other components in panavia 21
What are the various primers to be used with panavia?
ED primer: enamel and dentine
Alloy primer: metals and alloys
Clearfil Primer: for ceramic
How does primer work ?
Forms a bond with enamel the same way as the MDP resin since it contains MDP and initiates setting of the panavia too since without panavia will only reach 50% polymerisation
Which ceramics do not need to be etched when using Clearfil primer?
Zirconia and alumina based
What are the properties of panavia
Radiopque due to barium
Heavily filled with particles fro, 40nm to 19 microns
Film thickness of around 24 mincrons due to size of the biggest filler
Leaches fluoride
Can be auto cure and light cure
What are silane coupling agents?
Siloxane linkages form to the Si in ceramic
Cross linkage between coupling agents
Polymerisation between the resin and meathcrykate
