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44 Cards in this Set
- Front
- Back
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What are the two main polymerization reactions seen in dental materials |
Free Radical polymerization Monomer |
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What is Free radical polymerization |
Very common mode Examples: Variety of polymers and plastics (Dental bases, cements, adhesives, sealants, and other composite materials) |
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What is the Monomer reaction |
Also known as the reactive group or functional group Determine the physical and chemical properties of polymer |
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What is the functional group for the Monomer |
is c=c carbon to carbon double bonding
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What is the steps in addition polymerization |
Initiation Propogation Termination |
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What is the initiation step |
Has two phases |
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What is phase one of the initiation step |
free radical formation |
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How is phase one achieved |
application of heat, light, or chemical reaction |
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What is Phase 2 |
Free radical that has formed is now reacting to a C=C bond to a C-c with another unpaired electron at the end of the chain |
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What is the Propogation step |
Same process as phase 2 of initiation growth and lengenthing of the chain also adds 2nd 3rd and 4th monomers |
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What is the termination stage |
Two chains contacting and terminating each other or the introduction of contaminants will terminate the reaction |
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What are 3 different modes of activaton |
Heat (heat cure) Light (Light cure) Chemical (Cold cure) |
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Heat activated acrylic resigns typically use what |
Benzolyperoxide as the initiator |
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Chemically activated acrylic resigns and composite materials also commonly use what |
Benzulyperoxide (BPO) as the initiator |
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What is used as the activator for the chemical activated method |
Tertiary amines (nitrogen connected to 3 carbons) |
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The Light activated method is activated by what |
Absorbs light and then inititats the polymerization |
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What is dual cure |
A material that cures via light and chemical means |
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Additional polymerization is what type of reaction |
Exothermic reaction |
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The reaction of chemically activated materials is initially delayed for several minutes by the prescence of a chemical called what |
Inhibitor |
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Inhibitor is typically what |
Hydroquinone |
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What does the inhibitor hydroquinone do |
Destroys the first free radical that are produced To delay the progression of the reaction Allows for manipulation of the material |
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TRUE OR FALSE Shelf life does exist, and if left to long a free radical forming in a container of monomer could possible polymerize the entire content |
TRUE |
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WHAT ARE SOME CONFLICTS WITH UNFILLED RESIGN (3) |
Polymerization shrinkage Coeffienct of thermal expansion Strength and Abrasion resistance is lacking |
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COMPOSITE MATERIALS |
.............. |
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What are the two phases of a composite material |
Matrix Filler |
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What does the Matrix do |
creates the solid mass and bonding to tooth structures
consist of diluent (additive that controls viscosity) |
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What does the filler do (3) |
compensate and resolve the weakness of the maxtrix by itself Increased filler=increased composite strength Resulting product is similiar to a natural tooth |
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What does the filler decrease the chances of |
Decreased coeffiecient thermal expansion Polymerization shrinkage |
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What is a silane coupling agent (2) |
Not a true phase in composite materials Allows to different surfaces to be compatible |
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What are macrofilled composites (4) |
1st type developed Quartz Large particles ( restoration feels rough) (greater plaque and bacterial attachment) Not ideal for posterior teeth (wear resistance) |
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What is the microfilled composites |
Much smaller than macro Finished and polished to a smooth surface |
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What is a positive and is a disadvantage to a microfilled composite |
They require more resign (less filler for strength) Resign is pre-polymerized less chance for shrinkage |
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What is a hybrid composite |
Bended composite Contains various sized particles more estetic (retaining more of the elasticity and strength) |
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What is the improved hybrid |
Increased number of nano particles Decrease the resign filler ration while retaining strength, esthetics, and physical properties |
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Describe flowable composites |
flow into the cavity used as the initial increment of a composite and then covered by a hybrid |
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Describe condensable |
Thicker stiffer feel composites that can be compacted |
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What are some factors that can affect the placement of composites (4) |
Depth of cure Incremental addition Air Inhibition Unreacted C=C bonds |
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What happens if the innermost portion of a restoration is not fully covered |
pulpal irritation post operative sensitivity |
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GLASS IONOMER MATERIALS |
................ |
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What are the different glass ionomer materials (5) |
Chemical cure glass ionomer Resin modified glass ionomer Acid base chemically activated resign modified glass ionomer Recharging glass ionomer Componers |
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Describe chemical cure glass ionomer (4) |
Acid base reaction Fl releasing Chemical cure Crazing can occur (dehydration of the material) First true adhesive material |
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Describe resign modified glass ionomer |
Acid base reaction/polymerization via light or chemical reaction |
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Describe the acid base chemically activated resin modified glass ionomer |
Superior Most sought after for luting/ cementing PFM or metal crowns Needed for instances where direct light cannot access the material |
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What is a componer |
Composite that releases an initial amount of Fl |
