Cementation Flashcards
Layers of tooth
Dentine
Enamel
Restoration - Cement
Restoration (metal, ceramic, composite resin)
Most commonly used
Composite resin
Procedure
Metal and metal ceramic restorations
Metal and ceramic endodontic posts
All-ceramic reinforced core ceramics
Resin bonded bridges
Precious metal bonding e.g intra-oral repair
Resin-bonded ceramics
Composite restorations
Fibre reinforced resin bridges
Fibre reinforced endodontic posts
Conventional cementation - non adhesive
Etching
Gritblasting
Tin plating
Silica coating
Metal primers
HF etch + silane
Resin to resin bond
Luting agents for:
Metal and metal ceramic restorations
Metal and ceramic endodontic posts
All-ceramic reinforced core ceramics
Resin bonded bridges
Precious metal bonding e.g intra-oral repair
Resin-bonded ceramics
Composite restorations
Fibre reinforced resin bridges
Fibre reinforced endodontic posts
Zinc phosphate cement
Zinc polycarboxylate cement
GIC, RMGICs, Compomers
Dark cure resins
Adhesive resins
Dark cure resins
Adhesive resins
Aesthetic dual cure resins
Aesthetic dual cure resins
Adhesive resins
Conventional cementation
Zinc cements
GICs
Resin-modified GICs
Polyacid-modified Resin composites
Zinc phosphate composition
White powder - zinc and magnesium oxide
Clear liquid - 45-64% aqueous solution of phosphoric acid
Advantages of zinc phosphate cement
Easy to mix
Sharp and well defined set
Low cost product
Disadvantages of zinc phosphate cement
Risk of pulpal irritation due to low pH No antibacterial action Brittle No adhesive qualities Relatively soluble in oral environment Low tensile strength
Zinc polycarboxylate cement e.g ?
Durelon
White powder - zince with magnesium oxide and stannous fluoride
Clear liquid - 30-40% aqueous solution of polyacrylic acid
Advantages of zinc polycarboxylate cement
Bond to enamel and dentine as well as some of the metallic cast restorations Low irritancy Antibacterial action Low film thickness Fluoride release
Disadvantages of zinc polycarboxylate cement
Properties are highly dependent upon handling procedures
Short working times and long setting times
Bonding needs to be exact
Clean up difficult
Timing critical
Strength and solubility are comparable to zinc phosphate cement
Less adhesion than GIC and resins
GIC
Indications
Problems
Popularity
Suggestions for use
Fluoride release
Bond to tooth
Low expansion/contraction
Moderate strength
Some post-op sensitivity
Water sensitive during setting
Moderate/high popularity
Good for routine use on crowns and bridges
Suggest the use of a prep desensitiser
RMGIC examples
Fuji PLUS
Rely-X
Protec-Cem
Compomer/RMGIC
Strengths
Weaknesses
Popularity
Use suggestions
Fluoride release Bond to tooth Moderate-high strength No post op sensitivity Low solubility
Little long term experience, SWELLING
Low
Routine use on metal supported crowns and bridges, lab manufactured composites
Resin bonding to alloys
Interfaces involved
Examples of use
Tooth resin interface/resin metal interface
Resin bonded bridge (Ni-Cr)
Orthodontic bracket (Steel, Co-Cr, Ti)
Intra-oral repair (Au and Pd)
Composite resin facings (Au and Pd, Ni-Cr, Co-Cr, Co-Ni-Cr, Ti)
Self adhesive resin cements
• Easy to clean • Dual Cure • Need light cure as well as chemical cure to ensure full conversion • Colour • MaxCem Elite and SmartCem2 claim better translucency and better colour stability • Panavia SA Cement may be too opaque • Enamel Bond • Significantly better with acid etching, thus not ideal for veneers, inlays, onlays, RBBs and orthodontic brackets • Dentine Bond • Not as good as that obtained with DBAs • Acid etching compromises the bond • Bond may be enhanced by pre-treatment with PAA • Bond to Fibre Posts • Enhanced when using a silane • Bond to Zirconia • Enhanced by using a ceramic primer
Precious metal alloy bonding/intra oral repair uses the method of..
Success rate
Silica Coating
Poor
Types of silica coating
Layers
and mechanism
Silicoater - mixture of silane coupling agent and silica coating
Tribochemical coating - works by causing advancing particle to rebound off coated surface
Metal > silica coating layer from blasting > silane coupling > composite on top
Ideal cement
Long working time Low film thickness Low solubility High compressibility and tensile strength Low viscosity Adhere to tooth structure e.g in DBC Biocompatible Cariostatic Translucent/appropriate opacity Radiopaque
Acid/Base cements
Zinc phosphate
Zinc polycarboxylate
GIC
ZO cements
Resin modified cement
Resin modified GIC
Polyacrylic modified resin
Polymeric cements
Hydrophobic resin
Hydrophilic resin
Self etching resin
Provisional cements
Resin-bonded bridge
Examples of cement
Phosphonated Panavia
4-META Superbond
Self-adhesive Rely-X
Resin Cements
Strong
Adhesive
Technique sensitive
Chemical, dual or light cure
Hydrophobic
Use
Technique sensitive Translucent ceramic use Adhesive bridge bonding Requires bonding agent Light/dual cure Glass ceramic
Hydrophilic
High affinity to non precious metals Adhesive metal bridges Expensive O2 inhibited Chemical/dual cure
Self-etch resin
Easy to use
Self adhesive to dentine
Crown retained bridges
Bonding provisional adhesive bridges
Metal primers
Can be used instead to do intra-oral repair
Fewer stages
Enhance bond strength
Resin bonded ceramics - DBCs and glass ceramics e.g
Lithium disilicate
Etch dissolves glass portion and material integrates into structure
Mechanism at glass-resin interface
Silica oxide and methacrylate bonds at surface. HF etch. Coupling agent integrates as oxide layer
Aesthetic resin luting agents - types
- Light activated –> Veneers
2. Dual Cure –> Ceramic crowns
Resin-to-resin bond - used for
- Incremental build up of direct composites
2. Prefab resin composites e.g onlays
Cementing temporary restorations - why are they needed
- Pain
- Overeruption and space loss
- Drifting of proximal teeth
- Damage to core preparations
Functions of temp cement
Provide seal Prevent marginal leakage Prevent pulpal irritation Low strength to allow easy removal Protect preparation
Ideal properties of temporary cement
Ability to seal against oral fluid leakage Strength for easy removal Low solubility Biocompatible Chemicocompatible Easy use Ease of eliminating excess Compatible with final luting agent
Materials used for temp cement
What not to use
Fine particle ZOE
Non-eugenol cement
Zinc phosphate, zinc polycarboxylate and GIC are too high strength
Advantages of ZOE
Easy removal
Acceptable sealing
Easy to use
Good for pulp
Disadvantages of ZOE
Reduces surface hardness and strength of methacrylate resin
Can affect bond strength of resin cements
ENSURE all cement removed
