Cements Flashcards
What does HF acid do?
- Creates micromechanical retention (creates an irregular, retentive surface)
- Etch 20 seconds for EMAX, 60 seconds for Empress
Why do we use the two-component non-hydrolyzed silane coupling agent compared to the one component?
The one component prehydrolyzed is prone to degradation - needs to be refrigerated
How does a Silane Coupling Agent bond to ceramic?
It’s a bifunctional molecule…
- Covalent bond to silca in ceramic
- Covalent bond to methacrylate in resin via carbon double bonds via free radical polymerization
What has the highest shear bond strength (MPa) when comparing all the primers?
Bis-Silane
What’s a good product to use if you have saliva contamination?
Ivoclean
Use before silane coupling agent if there is saliva contamination
What does MDP bond to?
The phosphate group binds to minerals around collagen
What can strong air abrasion do to tetragonal zirconia?
Create a phase change in zirconia from tetragonal to monoclonic
What products contain MDP?
Cements: Panavia
Primers: Z-Prime
Can you name 2 Bifunctional Monomers?
MDP
4-META
What Ceramic Primer showed the most promisng Shear Bond Strength (MPa) to Zirconia?
Z-Prime Plus
(Contains Primarily MDP)
What chemical activator enhances a material to dual cure?
Aryl Sulphinic Acid
If you had to pick either “universal” or “non-simplified” as well as either “self-cure” or “dual-cure” to get the best bond strength to dentin with resin cements, which would you choose?
Non Simplified
Dual Cure
What are advanges of Resin Cements?
- High tensile strength
- High compressive strength
- Bonds to tooth AND restoration
What are some disadvantages to Resin Cements?
- Potential allergen
- Pulpal sensitivity
- Technique Sensitive (Hard to clean up!)
- Cost
What is the composition of Resin Cements?
- Cross-linking monomers (Bis GMA or urethane dimetharcrylate resin)
- Functional monomers (MDP, 4-META)
- Inorganic Fillers (silica, barium glass, ytterbium trifluoride)
- Initiators, Activators, Inhibitors, Pigments
What are 3 different polymerization mechanisms?
- Self Cure
- Light Cure
- Dual Cure
What are 3 different surface treatments for Resin Cements?
- Etch and rinse
- Self etch
- Self adhesive
What are 3 different types of monomers in regards to resin cements?
- Esthetic (Pure Bis GMA)
- Adhesive
- Self Adhesive
Describe the Self Cure mechanism…
- Does not react with a light
- MIx separate pastes (benzoyl peroxide initiator/tertiary armind activator)
- Free radicals produced
- Radicals attack carbon double bond of monomer
What is an application for Self-Cure Cements?
- Useful where light can not penetrate (resin-bonded FDPs - metal present)
- Fast, strong set
- Air-inhibited
- Excess cement difficult to remove
Describe the Light Cure mechanism…
- Photo-initiator in resin (camphorquinone)
- Abosrbs photon energy
- Combines with activator (amine)
- Creating free radicals
- Initiates Polymerization (monomers and Bis-GMA)
What are some advantages to Light Cure?
- Longer working time
- Greater Polymerization
- Greater color stability
What is a disadvantage for Light Cure cements?
Light attenuation through restoration
Attenuation in fiber optics, also known as transmission loss, is the reduction in intensity of the light beam (or signal) with respect to distance travelled through a transmission medium
What is a clinical example of using a Light Cure Only Cement?
- Light must reach cement (ceramic veneers)
- Multiple Shades
Describe Dual Cure Cements…
- Both reactant types: light cure and self cure
- Polymerize with/without light: ceramic inlays, onlays, crowns, FDPs, posts
- Less polymerization if not completely light cured
Is NX3 an example of a dual cure cement?
Yes!
It is light and dual cure
Describe the machanism of action for Self Cure…
- Peroxide Initiator
- Aromatic TERTIARY AMINE activator
- May oxidize - color shift
What are some advantages of Esthetic Resin Cements like NX3?
- Multiple Shades Available
- STRONGER MECHANICAL PROPERATIES THAN SELF-ADHESIVE RESIN CEMENT (RELY X UNICEM)
- Light cured and dual cured
- Requires seperate primer (MDP or silane)
- Requires bonding agent (bonding to tooth substrates)
- Cross-linking monomers only
Describe the Light-Cure mechanism…
- CQ initiator
- Aliphatic Amine Activator
What kind of cement is RelyX Unicem?
RMGI - Self-Adhesive Resin Cements
Great for metal restorations!
What kind of cement is Ketac Cem?
Ketac cement by 3M is a permanent glass ionomer luting cement that offers fluoride release - it is considered a self-adhesive resin cement
Indicated for Metal/Glass Free Restorations!
Describe some characteristics of Adhesive Resin Cements…
- Stronger mechanical properties than self adhesive resin cement (Ketac Cem, Rely X Unicem)
- Can bond directly to Zirconia or base-metals using MDP as a functional monomer
- Requires seperate silane for glass-ceramic restorations
- Requires bonding to tooth structure
- Contains acidic and crosslinking monomers
What are some properties of Self-Adhesive Resin Cements?`
- Contains acid monomers
- Self Etching - no bonding agent - MDP bonds directly to mineral content of dentin
- Requires seperate silane (for glass ceramic restorations)
- Can bond directly to Zirconia and Base Metals
- WEAKER MECHANICAL PROPERTIES RELATIVE TO ESTEHTIC OR ADHESIVE RESIN CEMENTS
- Dual Cured
- Limited Shade Selection`
When discussing Adhesive Resin Cement, Esthetic Resin Cements, and Self Adhesive Resin Cements, Which 2 have the higher flexural strength?
Adhesive and Esthetic Resin Cements
When comparing Adhesive, Esthetic, and Self Adhesive cements, which 2 have the higher compressive strength?
Adhesive and Resin Cements
What have clinical studies found about self-adhesive resin cements?
Lower sensitivity for post cementation,
