Outcome 4 - Composite

Question 1

Organic definition

Answer 1

Derived from an animal or plant source

Question 2

Inorganic definition

Answer 2

Compounds that are not derived from a living source, usually from a mineral source

Question 3

Resin definition

Answer 3

A soft organic compound, usually an exudate from a plant source

Question 4

Polymerization definition

Answer 4

To cause a simple resin to change into another form, usually one that has a stronger molecular structure, thus hardening the material

Question 5

Photo polymerization definition

Answer 5

Polymerization caused by an exposure to a concentrated light source

Question 6

Auto polymerization definition

Answer 6

Polymerization caused by chemical reaction

Question 7

Micro-mechanical retention definition

Answer 7

a material locking into a structure through microscopic voids or tags

Question 8

Chemical adhesion definition

Answer 8

Materials creating a molecular bond to each other during polymerization process, for example, layers of composite resin restorative material will chemically adhere to each other and become one solid mass

Question 9

Pros of Composite Resin

Answer 9

-esthetically pleasing
-able to withstand the oral environment
-sufficient strength to withstand occlusal forces

(not as strong as amalgam or gold but often that superior strength is not necessary)

Question 10

The components of composite resin include:

Answer 10

-Organic Resin Matrix
-Inoranic Filler Particles
-Coupling Agent
-Pigments

Question 11

What is the Organic Resin Matrix?

Answer 11

a material called BIS-GMA, compromised of demethacryate with additives to allow polymerization, is the main component of the resin matrix

BIS-GMA is a viscous liquid that is not strong enough to be used on its own as a restorative material

Question 12

What is the purpose Inorganic Filler Particles?

Answer 12

These particles add the strength, body, and light reflection qualities necessary to transform BIS-GMA into a restorative material.

Question 13

What are the most common fillers in Composite?

Answer 13

Common fillers are quartz, glass, and silica

Question 14

How much filler in Composite?

Answer 14

The amount of filler present in the composite restorative material as well as the size of filler particles vary from product to product

Question 15

How are Composites classified?

Answer 15

Classified by particle size and percentage of filler particles in the total product.

Macrofilled
Microfilled
Hybrid
Flowable
Sealant

Question 16

What is a Macrofilled composite?

Answer 16

Contain the largest inorganic filler particles and are of superior strength

Question 17

What is Microfilled composite?

Answer 17

Contain the smallest inorganic filler particles and have superior esthetics with excellent smoothness and light reflection qualities.

Question 18

What is Hybrid composite?

Answer 18

Most often used today.

Contain a mixed range of particle sizes and have a high wear resistance and excellent shading capabilities

Question 19

What is Flowable Composite?

Answer 19

Are supplied as a hybrid or nanofilled composite with enough filler to make them wear resistant. Material is designed to flow into more conservative preparations.

Question 20

What are sealant composites?

Answer 20

Resemble flowable composites
Require no preparation with the handpiece or hand cutting instruments. They are applied to the etched enamel surface

Question 21

What is the Coupling Agent in Composite resin?

Answer 21

This additive is necessary to bond the filler particles to the resin matrix to prevent settling. The filler particles are coated with an organosilane compound, simply referred to as silane. The organic portion bonds the resin matrix and the silane portion bonds with the inorganic fillers, holding all components together.

Question 22

What are the Pigments in Composite resin?

Answer 22

Composite resins are designed to blend with tooth strucutre. Manufactures add pigments to match various tooth colours, ususally from an inorganic substance.

Question 23

Biocompatibility of Composite Resin

Answer 23

There is no controversy regarding the biocompatibility of the material, as it contains no hazardous components.

Question 24

Is Composite Resin Mechanically Stable and Durable?

Answer 24

Although not as strong as a metal restoration, advances in the chemical composition of the material, as well as cavity preparation and placement techniques have enabled dentists to use composite resin in a large variety of restorative situations.

Question 25

Is Composite Resin resistant to corrosion and chemicals?

Answer 25

Composite resin is basiclaly a plastic material, so it is resistant to corrosion and deterioration in the moist and acidic oral environment.

Question 26

Is Composite Resin dimensionally stable?

Answer 26

The composite resin material has an expansion and contraction factor that is more simmilar to tooth structure than amalgam. There is still some concerns with excessive contraction of the restoration in cold environments, but ongoing research into manipulation of the chemical composition of the material and compatible bonding materials is reducing the microleakage factor.

Question 27

Does Composite Resin have minimal thermal and electrical conductivity?

Answer 27

The thermal conductivity of composite resin is less than that of metal restorations, but the placement technique must be very precise. Variations from the recommended restorative protocol can lead post-placement sensitivity, even though the material does not readily conduct thermal sensation.

Question 28

Is Composite Resin Esthetically pleasing?

Answer 28

- is available in a wide variety of shades - the shade guide that accompanies the material enables the dental team to match the restoration to the surrounding tooth structure very closely. Finishing and polishing procedures can also create luster and light reflection similar to that of enamel.

Question 29

Is Composite Resin Easy to Manipulate?

Answer 29

Is supplied as a paste that can easily conform to the contours of a cavity preparation. There are two methods of hardening the material after placement: either by chemical reaction or exposure to a hand-held light. The contouring, finishing and polishing procedures vary with differeny brands and operators, but time and cost are usually reasonable.

Question 30

Does Composite Resin Adhere to Tooth Tissues?

Answer 30

There are many bonding techniques available to allow composite resin restorations to adhere to the remaining tooth structure. This remains one of the main advantages of this material.

Question 31

Is Composite Resin Tasteless and Odorless?

Answer 31

Is tasteless and not at all unpleasant in the oral environment. It is smooth and easily cleaned by the patient.

Question 32

Is Composite Resin Easy to Repair and Clean?

Answer 32

Repair of fractured restorations is possible in some cases by adding material

Question 33

Is Composite resin Cost Effective?

Answer 33

The placement cost of a composite resin retoration is higher than that of an amalgam restoration. This is due to the material cost, longer chair time required or placement and cost of finishing and polishing materials not required in amalgam dentistry. Most patients will still find the composite resin restoration within their budget, but others may opt for amalgam in posterior situtations for financial reasons.

Question 34

The two methods for achieving polymerization are:

Answer 34

light curing (photo-polymerization) or auto-curing (auto-polymerization)

Question 35

What does light curing involve?

Answer 35

Exposure of the composite resin to a high intesity blue light. The blue wavelength of light is most effective for polymerization and is created by a combination of halogen light and a tungesten refraction device

Question 36

What does Auto-curing involve?

Answer 36

involves mixing catalyst and base materials to initiate a chemical reaction

Question 37

How long to light-cure composit resin?

Answer 37

The exact exposure time for complete polymerization depends on the manufacturer’s directions, the thickness of each layer of composite being placed and the shade of the material. Most manufacturers recommend between 20 and 60 seconds of exposure per layer. If the dentist places a layer of material thicker than that recommended, the light exposure time will need to be increased.

Question 38

Does darker shades of composite resin require more or less light curing time?

Answer 38

Darker shades of composite require longer curing times to allow the light to fully penetrate the material.

Question 39

When are auto-polymerized materials recommended?

Answer 39

Auto-polymerized materials are recommended when it’s unclear if the light will be able to fully reach all aspects of the restoration.

Question 40

What is Acid Etch or Tooth Conditioner

Answer 40

Acid etch or tooth conditioner is a material composed of 10-37% phosphoric acid. It is supplied as either a gel or a liquid. The acid dissolves the mineral component of the tooth structure on a microscopic level to create tags and pores into which bonding materials can flow. The tags and pores create micro- mechanical retention for the composite resin restorations.

Question 41

What is a Bonding Resin? (Adhesive)

Answer 41

Placed after acid etch and primer. May also be called adhesive or unfilled resin, as it is almost pure BIS-GMA. The bonding resin is thicker and more viscous than the primer, so it would have difficulty flowing into the microscopic pores and tages. The bonding resin is attracted to the primer and so is pulled more deeply into the etched surface than if the primer was not used. One layer is usually all that is necessary

Question 42

Does composite bonding systems require curing?

Answer 42

Some bonding systems require light curing after the placement of bonding resin, while others utilize a chemical-cure reaction by mixing base and catalyst resins.

Question 43

Placement of Composite Resin

Answer 43

The BIS-GMA in the composite will molecularly bond to the BIS-GMA of the adhesive resin, so the composite is held into the tooth preparation by micro-mechanical retention.