What are the different mechanisms of adhesion?
- Mechanical
- Physical
- Chemical
What is the simplest form of adhesion?
Mechanical
Which adhesion is from interlocking of components?
Mechanical
Which adhesion involves 2 surfaces in close proximity?
Physical Adhesion
Through dipole-dipole interaction between polar molecules
What type of bonding is rapid, reversible and not suitable for permanent bonding?
Physical Adhesion
What happens with chemical adhesion?
- Molecules dissociate after adsorption onto the surface and constituent component then bond themselves separately by covalent or ionic forces
Which adhesion involves the sharing of electrons between the 2 atoms?
Chemical Adhesion - which distinguishes it from physical adhesion
What are the different adhesion promotors?
- Coupling agents
- Primers
How do coupling agents differ from primers?
- Coupling agents
- Bonds to both materials involved
- Silane
- Primers
- Modifies the surface of one of the two materials involved so a bond can be created
- Rely-X Ceramic Primer
What is a material that fills the gap between the tooth and the indirect restoration and holds them together called?
Luting agent
What are some desired properties of luting agents?
- Good working/setting properties (long working time, short setting time)
- Adheres well to tooth and restoration
- Good seal
- Biocompatible
- Good tensile and shear strength
- Compressible
- Low film thickness (25 microns or less)
- Low viscosity/solubulity
What are the types of cements?
- Provisional/temporary cement
- Permanent cement
What are the zinc-oxide based, self cure provisional cements?
- Tempbond
- Tempbond NE
- TempoCem
- Tempocem NE
What are the resin based, dual cure provisional cements?
- Tempbond Clear
- Provilink
What type of paste is tempbond/tempbond NE?
Base & Catalyst
What are some characteristics of Eugenol?
- Residual eugenol may inhibit the polymerization of resin material
- Provides a “sedative” effect on pulp
- May be used to provisionally cement
What is the main reason to use Provilink - Tempbond Clear?
Resin based-dual cure
**Because the color is clear **
Which permanent cements are acid-base reactions?
- Phosphate
- Phenolate
- Polyacrylate
What is the oldes cements still be used, from what date, and what film thickness?
- Zinc Phosphate
- 1878
- < 25 microns
What are the disadvantages of zinc phosphate cement?
- Does not bond to tooth
- Soluble in oral fluids
- Opaque color
- Very low pH
What are some characteristics of polycarboxylate cement?
- Zinc oxide + polyacrylic acid
- 1968
- Film thickness <25 microns
- Adheres to stainless steel & tooth
- Little pulpal irritation - large molecules can’t penetrate dentinal tubules
What are the disadvantages of polycarboxylate cement?
- Need to work fast - (30 secs) sudden rapid increase in viscosity
- More difficult to remove than zinc phosphate
- Not recommended for permanent, good for provisional cementing
What are some characteristics of glass ionomers?
- Glass powder, fluoride
- Glass particles surrounded by silica gel with acid
- Isolation essential for entire setting time
- Protect with resin coat
What are the Working Time, Mixing Time, and Setting Times for glass ionomer?
- Working time - 2-3.5 min
- Mixing time - 10-30 sec
- Setting time - 6-9 min
