1. Inert ceramics - porcelain
2. Reactive ceramics (ZnO and glass-ionomer cement powders)
3. Refractory ceramics (SiO2)
4. Ceramics as abrasives

Reactivity - metal higher; CERAMIC LESS

Safety - metal lower; CERAMIC BETTER

Chemical durability - metal lower; CERAMIC BETTER

Mechanical properties - METAL HIGHER; ceramic lower

Esthetics - metal poor; CERAMIC CAN BE GOOD 

1. Bond ceramic to another material
2. Incorporate a component which can hinder propagation of cracks through the material
3. Use 'transformation toughening'

1. Alumina
2. Boric oxide
3. Calcium oxide
4. Feldspars
5. Kaolin
6. Leucite
7. Silica
8. Silicon carbide
9. Zinc oxide
10. Zirconium oxide

1. Powder-slurry
2. Casting, etc.
3. Pressable ceramics
4. Machinable ceramics (CADCAM)
5. Glass-infiltration techniques
6. Surface treatments

Household porcelain: 50% kaolin, 25% feldspar; 25% quarts

Dental is feldspathic (no kaolin too brittle and opaque) 

High fusion 1200-1400 C

Medium fusion 1050-1200 C

Low fusion 800-1050 C 

• Core porcelain - the basis of the restoration requiring good mechanical properties
• Dentin or body porcelain - more translucent than core porcelain
• Enamel porcelain - for areas of max. translucency ie at incisal edges

Alumina - hinders crack propagation

Leucite - creates compressive stresses as crack deflectors

Zirconia - transformation toughening

1. Compacting - removing water to avoid shrinkage
2. Firing - slow and uniform
3. Cooling - slow and uniform
4. Refiring - add material to compensate for shrinkage
5. Glazing and staining

Biocompatability - excellent

Interface - adhesion difficult to achieve because it is inert 

Chemical - excellent (inert)

Mechanical - brittle

Esthetics - Excellent

Practicability - on firing 30-40% shrinkage; cant be used as inlay because of leakage 

1. Porcelain fused to metal - good esthetics and mechanics
2. castable ceramics - less dimensional change
3. machinable ceramics - able to use zirconia which can't be fired
4. pressable ceramics
5. infiltrated ceramics
6. zirconia based materials - high strength and toughness

feldspar

alumina

zirconia 

• Micromechanical - bonding occurs through microabrasions on surface of metal copin
• Chemical bonding - occurs through oxide links

• closing spaces
• restoring chipped teeth
• whitening permanently stained or discolored teeth
• correcting uneven or crooked teeth

• Very conservative
• Excellent esthetics
• Strong and durable when combined with the greater tooth structure

1. Dimethylacrylate polymers
2. Inorganic fillers
3. Coupling agents
4. Polymerization inhibitors
5. Initiator/activator system
6. UV stabilizer

• adhesion between polymer and filler (through coupling agent)
• filler should be more rigid than polymer
• filler can act as a load-bearing component of composite

• Can improve compressive strength
• Increase hardness
• Less setting shrinkage
• Lower coefficient of thermal expression
• Radiopacity
• May be a contribution to esthetics 

1. amalgamation
2. polymerization
3. acid-base rxn
4. acid base and polymerization 

• Resotrative materials
• Provisional restorative materials
• Cementing metal castings and ceramic restorations, veneers
• Bonding ortho appliances
• In conjunction with restorative materials

1. Calcium hydroxide
2. Zinc oxide non-eugenol
3. Zinc oxide eugenol
4. Zinc polycarboxylate
5. Zinc phosphate
6. Glass-ionomer
7. Resin-modified glass-ionomer
8. Resin cement
9. Adhesive resin cement

Acids:

Phosphoric acid (PHA)

Poly(acrylic acid) (PAA)

Eugenol (EUG)

Bases:

Zinc oxide (ZnO)

Fluoro-aluminosilicate glass (FAS)

Zinc phosphate (ZPH)

Zinc oxide-eugenol (ZOE)

Zinc polycarboxylate (ZPO)

 Glass-ionomer (G-IC)

• All powder-liquid materials
• Cement liquids are acids (proton donors or elec. acceptors)
• Cement powders are bases
• A-B rxn occurs on mixing
• Not all powder reacts
• Set structure is heterogenous (unset powder + rxn product = cored structure)

- Opacity causes ZPH, ZOE, and ZPO to be yellow/opaque; FAS is transluscent and more esthetic

- ZPO not as strong as glass ionomer cement (Zno is generally weaker than FAS) 

-FAS can potentially deliver fluoride 

• PAA chemically attacks surface of FAS glass generating calcium and aluminum ions and setting cement
• Fluoride ions are released and are not part of the set material
• Fluoride ions migrate out without affecting strength or structure

PHA - very acidic, irritant?, and no chemical adhesion

PAA - water soluble, non-irritant, adhesive (reacts with Ca of tooth)

EUG - forms zinc euenolate (which slowly disintegrates in H2O); obtundent (blunts pain); bacteriostatic; interferes with composite setting  

• Sealing tubules to eliminate post-op pain
• Reinforce the tooth
• Eliminate microbial microleakage
• Eliminate amount of tooth prep
• reduce dependence on mechanical retention

Chemisorption occurs when a chemical rxn has taken place (usually irreversible);

Physical adsorption where Van der Waals forces operate and are more reversible 

1. chemical reactivity
2. physical form (roughness)

1. chemcial bonding [glass ionomer cement to tooth substance]
2. micromechanical adhesion (liquid in pores or crevices producing interlocking) [adhesion to etched enamel]
3. hybridization bonding (one phase penetrates by diffusion into surface of a second phase) [bonding to dentin]

Make surface clean, rough, and chemically reactive by:

• etch
• wash
• dry (for a high surface energy)
• and apply 

• conditioner -removes some surface (ie enamel etchant)
• primer - bonds to dentin
• adhesive - resin or adhesive applied to conditioned dentin

• remove smear layer
• open and widen dentinal tubules
• demineralize intertubular dentin

1. Classify according to usage
2. Clasify according to time in mouth
3. Perform initial tests
4. Secondary tests
5. Usage tests

• Effect of alloy on the body
• Effect of the body on alloy (corrosion)

1. Liquid - problem when in contact w/ skin and w/ allergic responses
2. Vapor - very toxic crosses alveolar membrane
3. Intermetallic compound
4. Organometallic compound (methyl mercury for ex) very toxic!

• Pulpal problems
• Components may be leached from cement (silica, calcium, fluoride, and aluminum)