Reading: Intro to Composites

Question 1

Components of Silicate Cement

Answer 1

Acid-Soluble Glasses

Liquid contains: phosphoric acid, water, and buffering agent

Question 2

Silicate Cement was recommended for…

1.

2.

Answer 2

1. Small restorations in anterior teeth
2. high caries activity

Question 3

Average lifespan of silicate cement

Answer 3

4 yrs

Question 4

How to tell if silicate cement is failing

Answer 4

1. Discoloration
2. Loss of contour
3. Roughened Glass texture

Question 5

_______ = rate of dimensional change of a material/unit change in temperature

Answer 5

Linear Coefficient of Thermal Expansion

Question 6

If the linear coefficient of themal expansion ~~ LCTE of enamel

??? —higher/lower chance for creating voids at the jxn. of the material and tooth structure once temperatures change.

Answer 6

LOWER

Question 7

TERM – the amount of water that a material absorbs over time per unit of surface area of water.

(H2O/Time)/Volume

Answer 7

Water Sorption

Question 8

Materials with a higher filler content exhibit ____ water absorption values than materials with lower filler content

Answer 8

LOWER

Question 9

TERM – refers to a material’s ability to resist surface loss as a result of abrasive contact with opposingtooth structure, restorative material, food boli, and toothbrush bristles.

Answer 9

Wear Resistance

Question 10

Filler particle _____, ______, & _____ affect the potential wear of composites and other restorative materials

Answer 10

Size

Shape

Content

Question 11

True or False?

The location of the restoration in the dental arch and occlusal contact relationships affect potential wear of materials

Answer 11

TRUE

Question 12

The smoothness of the surface of the restorative material is especially needed with restorations near the ______ for good health

Answer 12

Gingiva

Question 13

What two things of the filler determine the smoothness of the restoration and abiltity to be finished and polished?

Answer 13

1. Size
2. Composition

Question 14

What type of composites are BEST for providing surface textures that are polishable, esthetic, and compatible with soft tissues?

Answer 14

1. Nanohybrid
2. Nanofill

Question 15

Because of ________ fillers in composite materials, the restorations are radiopaque in radiographs

Answer 15

Barium

Question 16

When viewing a radiograph–

Caries will be?

Composite will be?

Answer 16

Radiolucent

Radiopaque

Question 17

Why must composites appear radiopaque-like on a radiograph?

Answer 17

To distinguish between carious lesions which are non-radiopaque!

Question 18

When referring to the stiffness of a composite material—

The _____ the modulus of elasticity, the more rigid the composite material will be.

Answer 18

Higher

(and vice versa)

Question 19

What microfill composite is best for a Class V restoration?

1. Rigid Hybrid
2. More Flexible Hybrid

Answer 19

More flexible hybrid

Question 20

What can be used to potentially protecy the bonding interface from polymerization shrinkage effects

Answer 20

Stress breaking liners (with lower elastic modulus)

Question 21

Although polymerization shrinkage cannot be avoided, you should use careful with –

1.

2.

Answer 21

1. amount of material
2. Intsertion point of the material

Question 22

True or False?

Shrinkage does not usually affect preparations having all-enamel margins

Answer 22

True

Question 23

True or False?

Shrinkage can result in a gap formation at the junction of the composite and root surface?

Answer 23

True

Force of composite polymerization >> initial bond strength of composite to dentin of the root

Question 24

When placing a restoration on the root surface, what material should be used first if at all possible?

Answer 24

RMGI – release of fluoride

Question 25

The ______ the C factor is, the greater the potential for bond distruption from polymerizing effects

Answer 25

HIGHER

Question 26

What does C-Factor stand for

Answer 26

(# bonded surfaces)/ (#unbonded or free surfaces)

Question 27

Internal stresses can be reduced by 1. Soft-start or high intensity light? 2. Incremental or bulk fill? 3. RMGI and flowable or no liner?

Answer 27

1. Soft-start polymerization 2. Incremental 3. Yes- use a stress breaking liner such as flowable composite or RMGI

Question 28

If you INCREASE the amount of filler you will ________ the amount of shrinkage

Answer 28

DECREASE

Question 29

Self - Cure Composite Properties (NO LIGHT OF ANY KIND) 1. Mixture: \_\_\_\_\_&\_\_\_\_\_ 2. Mixing causes the risk for _____ \_\_\_\_\_\_ to occur 3. Is working time restricted? 4. Color Stability is lower or higher? 5. Direction of shrinkage is where?

Answer 29

1. Catalyst and Base 2. Air Inclusions 3. YES- also limits the finishing time before it sets 4. Lower because of poor stability of tertiary amines 5. Centralized towards center of mass

Question 30

Light-Cured Composite Properties (VISIBLE light) 1. Is working time increased or decreased? 2. Is the color stability increased? 3. Internal Porosity?

Answer 30

1. Increased working time 2. Color stability is increased 3. LESS internal porosity

Question 31

Plasma Arc Systems Properties (LED light) 1. Is heat generation an issue? 2. Is shrinkage increased or decreased? 3. Efficiency, Portability, Durable?

Answer 31

1. Yes - more stress 2. Increased 3. Yes yes yes

Question 32

What is the MAIN advantage to using composite?

Answer 32

It's ability to bond to tooth structure

Question 33

Indications for composites (+) Name 7

Answer 33

1. Class I, II, III, IV, V, & VI restorations 2. Core build ups 3. Sealants and preventative resin restorations 4. Esthetic enhancement procedures -- partial veneers, full veneers, recontouring, diastema closure 5. Cements 6. Temporary Restorations 7. Periodontal Splinting

Question 34

If you are unable to completely isolate the field from liquids in the oral cavity, _______ should be used as a restorative material instead.

Answer 34

Amalgam

Question 35

True or False? Composite exhibits more wear resistance than amalgam

Answer 35

False -- generally amalgam does

Question 36

Name 3 contraindications to using composite

Answer 36

1. Isolation 2. Occlusion 3. Operator Factors

Question 37

Name 7 advantages to using composite

Answer 37

1. Esthetics 2. Conservation in tooth structure removal 3. Less complex tooth preparations 4. Insulating -- low thermal conductivity 5. Used universally 6. Bonds to tooth structure -- good retention, relatively low microleakage, and increased strength of remaining tooth structure 7. Repairable

Question 38

Name 5 disadvantages to using composite

Answer 38

1. Gap Formation @ root surface from polymerization shrinkage 2. More difficult, time-consuming, costly 3. Technique sensitive 4. May exhibit greater occlusal wear in areas of high occlusal stress or when all the tooth's occlusal contacts are on teh composite material 5. Has a higher LCTE -- potential marginal percolation if inadequate bonding technique is used

Question 39

Explain wedge placement and purpose

Answer 39

1. Depresses interproximal soft tissues 2. Shield the dam and soft tissues from injury during the procedure 3. Produces separation of teeth to help compensate for the thickness of the matrix that will be used later 4. Adequate wedging assists the eventual proximal contact restoration

Question 40

Wedge placement should be placed in the _____ embrasure

Answer 40

Lingual

Question 41

Problems with COMPOSITE PLACEMENTS:

Answer 41

1. Poor isolation of operating area 2. White line or halo adjacent to the enamel margin 3. Voids 4. Weak or Missing proximal contacts 5. Inaccurate Shade 6. Poor retention 7. Contouring and finishing problems

Question 42

The following list can contribute to --? 1. Poor contouring of the matrix band 2. Inadequate wedging 3. Movement of matrix band 4. Tackiness of composite 5. Matrix band is too thick

Answer 42

Weak or Missing Proximal Contacts

Question 43

Problems with shade selection may occur if --- 1. 2.

Answer 43

1. Tooth surface is not dried off 2. Poor lighting