Cementation Flashcards
What are the ideal properties of cement?
Long working time with rapid set Low film thickness Low solubility High compressive and tensile strengths Low viscosity Adhesion to tooth structure and restorative materials Biocompatible Cariostatic Translucency or opacity Radiopaque - contrast on radiographs
What are the different acid/base cements?
Zinc phosphate
Zinc polycarboxylate
Glass ionomer
ZO cements
What are the different resin modified cements?
Resin modified GIS
PA modified resins
What are polymeric cements?
Hydrophobic resins
Hydrophilic resins
Self-etching resins
Provisional cements
For: metal and metal-ceramic restorations e.g. FULL GOLD AND PFM
Metal and ceramic endodontic posts
All-ceramic reinforced core ceramics
What cements are used with what procedure?
Conventional cementation Zinc phosphate cement Zinc polycarboxylate cement RMGIC's Compomers
What is the presentation of Zinc phosphate?
White powder - zinc oxide
With 10% magnesium oxide and clear liquid of 45-64% aqueous solution phosphoric acis
What are the advantages of zinc phosphate?
Easy to mix
Sharp, well-defined set
Low cost
Low film thickness
What are the disadvantages of zinc phosphate?
Potential for pulpal irritation due to low pH and exothermic reaction
They have no antibacterial action
They are brittle
Low tensile strength
No adhesive qualities
Relatively soluble in the oral environment
What is the presentation of zinc polycarboxylate cements?
zinc oxide
10% magnesium oxide and stannous fluoride
Clear liquid 30-40% aqueous polyacrylic acid
What are the advantages of zinc polycarboxylate?
Bond to enamel and dentine and metallic cast restorations They have low irritancy Have antibacterial action Low film thickness Fluoride release
What are the disadvantages of zinc polycarboxylate?
Their properties are highly dependent upon handling procedures
They have short working times and long setting times
An exacting technique is required to ensure bonding
Clean up is difficult and timing is critical
Strength and solubility comparable to that of zinc phosphate
What are the different GIC’s used?
Aqua-cem
Fuji 1
Ketac-cem
Glass ionomer type I
What are the indications for using GIC
20 years of success fluoride release Bonds to tooth low expansion/contraction Moderate strength
What are the problems with using GIC?
Some post-op sensitivity
Water sensitive during setting
What are the use suggestions for GIC?
Routine use on crowns and bridges
Suggest use of preparation desensitiser (only used for PFM’s now)
What are the different RMGIC’s
Fuji plus
Rely-X-luting
Protec cem
What are the indications for RMGIC’s
Fluoride release Bond to tooth Low expansion/contraction Moderate-high strength - tensile strength higher than GIC No post-op sensitivity Low solubility - good acid resistance
What is the problem with RMGIC’s
Swelling - could crack with ceramic material used
What are the use suggestions for RMGIC’s?
Excellent for routine use on crowns and bridges - PFM and full gold crowns
Contraindicated for most ceramics
What are the strengths with poly-acid modified resin composites? (compomer cements)
Fluoride release Bonds to tooth with pre-treatment Moderate-high strength No post op sensitivity Low solubility
What are the problems with poly-acid modified resin composites
little long-term experience
Swelling
What are use suggestions for poly-acid modified resin composites?
Excellent for routine use on metal supported crowns and bridges, and lab manufactured composites
Available as chemical, dual or light cure
What are use contraindications for poly-acid modified resin composites?
Most ceramics
What are the clinical applications for resin-metal bonding?
Resin bonded bridge
Ortho bracket
Intra-oral repair
Composite resin facings
What are the 2 interfaces in resin bonded bridges?
Tooth-resin and resin-metal
What are the base metal alloy bonding for:
Resin bonded bridge
Ortho bracket
Composite resin facings
Resin bonded bridge Ni-Cr
Ortho bracket S/steel, Co-Cr, Ti
Composite resin facings Ni-Cr, Co-Cr, Co-Ni-Cr, Ti
What are the precious metal alloy bonding for:
Intra-oral repair
Adhesive FPD (bridge)
Composite resin facings
Au and Pd alloys for all
What is the procedure for cementing resin bonded bridges?
Etching, gritblasting to create a roughened surface
What is the luting cement for bonding resin bonded bridges?
Dark cure resins and adhesive resins
What is the procedure for cementing precious metal bonding?
Tin plating
Silica coating
Metal primers
What is the luting cement for precious metal bonding?
Dark cure resins
Adhesive resins
How do you go about cementing Maryland (Adhesive bridge)
Conventiona; Bis-GMA type resins
Chemical/dark cure e.g. Comspan
Surfaces etched to increase the SA
What are the adhesive resin cements for resin-bonded bridge?
Phosphonated resin e.g. Panavia 21 Kuraray - includes primers and etches, bases, and catalysts, oxyguard only sets in anaerobic environment
OR
4-META based resin e.g. superbond
What are the properties of resin cements?
Strong
Adhesive
Technique sensitive
chemical/dual/light cure
What are hydrophobic resins usually used for?
Translucent ceramics can bond on to the material Veneers and dentine bonded crowns Adhesive bridges Wide range of shades and opacities Light or dual cure
What are hydrophilic resins used for?
High affinity to non-precious metals
Adhesive for metal bridges
What are the properties of hydrophilic resins
High cost
Chemical or dual cure
Highly oxygen inhibited
e.g. panavia
What are self-etch resins used for?
All crown retained bridges and for provisional adhesive bridges
What are the properties of self-etch resins
Easy to use and clean up
Strongly self-adhesive to dentine
dual cure
What are the options for a silica coating for intra-oral repair?
Silicoater
Tribochemical coating - Rocatec and Cojet
How does Tribochemical coating work?
Advancing particle into the metal surface
Silicatise the surface at the point of contact - this improves the bond
What does the silica coating also need to bond the resin and metal together
Silane coupling agent
What is involved in the CoJet system?
CoJet material
ESPE-Sil
Visio-Bond
Sinfony Opaquer (masks out the metal colour)
What are the step for using the CoJet system?
Pre-treat with CoJet Apply ESPE-Sil Cover exposed metal surfaces thinly with Sinfony opaquer Light cure 10 secs Apply Visio-Bond, light cure 20 secs Complete with LC composite Light-cure Finish
What is the disadvantage of the CoJet system?
Doesn’t last long, can drop off
Many steps
Technique sensitive
What is the advantage of the CoJet system?
don’t need to cut the crown/bridge off
Effective in enhancing the bond strength to any alloy
What is the metal primer?
Why are they used?
Bifunctional monomer
They enhance the bond strength between precious metal alloys and resin
What are examples of resin-bonded ceramics?
Glass ceramics
Dentine bonded crowns
What is the procedure for cementing resin-bonded ceramics?
HF etch and silane
What is the luting cement for resin-bonded ceramics?
Aesthetic dual cure resin
What are the 2 phases pf glass ceramics?
Glass phase and crystalline phase
Why etch the glass ceramic first?
To dissolve the glass stage, cement infiltrates into the structure of the ceramic
What do dentine bonded crowns use?
Lithium disilicate
What is the bonding mechanism for resin-bonded cements/
Hydrophilic surface -> Methacrylate surface
Silicaloxide and methacrylate bonds made
Add coupling agent which bonds to the oxide layers as well
On restoration HF etch and or silane
On the prepared tooth total etch
Why do you get a higher strength bond using resin bonded cement compared to zinc phosphate or GIC?
Because it integrates into the material
What aesthetic resin luting cement is used for veneers?
Light activated - Porcelite
What aesthetic resin luting cements are used for ceramic crowns, onlays and inlays?
Dual cure Mirage FLC Nexus Calibra Variolink Rely-X ARC
Which restorations use resin-resin bond
Composite restorations
Fibre re-inforced resin bridges
Fibre reinforced endodontic posts
What are the luting cements for :
Composite restorations
Fibre re-inforced resin bridges
Fibre reinforced endodontic posts
Aesthetic dual cure resins
Adhesive resins
Where (mainly) do we need the resin-resin bond?
Incremental build up of direct composites
Prefabricated resin composites: inlays, fibre reinforced bridges and endodontic posts
How are the resin composites first fabricated?
Grit blasting or grinding
HF etching
Silane coupling agent
Tribochemical coating
What does loss or failure of the temporary restoration lead to?
Pain
Overeruption and loss of space
Drifting of proximal teeth
Damage to core preparations
What are the functions of temporary cementation?
Provides a seal Prevent marginal leakage Prevent pulpal irritation Low strength to allow easy removal - want to remove whole protect preparation
What are the ideal properties of temporary cementation?
Ability to seal against leakage of oral fluids
Strength consistent with intentional removal
Low solubility
Biocompatibility
Chemical compatibility with provisional polymer
Easy to use
Ease of eliminating excess
Adequate working and setting times
Compatibility with definitive luting agent
What materials are used for temporary cementation?
Fine particle zinc oxide eugenol cement e.g. Tempbond
Non-eugenol cements - TempbondNE - doesn’t have problems with resin based materials
Which cements cant be used because the strength will be too high?
Zinc phosphate
Zinc polycarboxylate
GIC
Difficult removal can damage the prep
What are the advantages of ZoE?
Easy removal enabling reuse of the restoration
Acceptable sealing properties
Obtundent effect on pulp
Ease of use
What are the disadvantages of ZoE
Free eugenol acts as a plasticiser of methacrylate resin and reduced surface hardness and strength
Eugenol can interfere with bond strength of resin cements
Must ensure all cement is removed prior to definitive resin cement
Eugenol free zinc oxide is available
