Composite Quiz

Question 1

Compare Composites vs. Glass Ionomers

Answer 1

Composites: Polymer (resin) base, static, mechanical properties comparable to amalgam, wear resistance was a concern, micromechanical retention (resin tags and hybrid layer), not self adhesive (adhesive required)

Glass Ionomers: Water base, dynamic/functional (fluoride reservoir), worse mechanical properties, good wear resistance, chemical bonds (ionic-not strong), self adhesive

Question 2

List pros and cons of posterior composites:

Answer 2

Pros

1. Esthetic
2. Conservative to tooth structure
3. Easier prep

Cons

1. Technique sensitive
2. Polymerization shrinkage effects

Question 3

List Indications and Contraindications of posterior composites

Answer 3

Indications

1. Small/moderate-sized Class I and II preps
2. Areas where esthetics are important

Contraindications

1. Inadequate moisture control
2. Heavy occlusal stresses
3. Larger preparation or more posterior location

Question 4

What is the Resin Matrix (soft/weak phase) of composite?

What is the filler (reinforcing phase)?

Answer 4

Small oligomers Bis-GMA and TEGMA

Irregular or spherical particles of silica

Question 5

Define Degree of conversion

Answer 5

The number of carbon double bonds of a monomer that are converted to single carbon bonds to form polymers

Question 6

If too much stress exceeds bond strength, then _____ and _____ results

Answer 6

Microgaps

Recurrent decay

Question 7

The two techniques to reduce polymerization stresses are:

Answer 7

1. Incremental/layering technique (horizontal or oblique)

2. Placing a low viscosity material such as flowable composite prior to composite

Question 8

What type and brand of composite do we use in clinic?

Answer 8

Nanohybrid
Herculite Ultra (Kerr)

Question 9

Less filler results in these composite qualities:

More filler results:

Answer 9

Slump and sticky

Increased viscosity

Question 10

What are the classifications of composite (by consistency)?

Answer 10

1. Conventional- putty like
2. Flowable- light
3. Packable (Condensable/Moldable/HD)

Question 11

Ideal distance of curing tip:

Ideal thickness of composite:

Answer 11

1 mm

1.5 mm

Question 12

Bulk fill advantages and concerns:

Answer 12

Advantages: more efficient

Concerns:

1. Depth of cure
2. Polymerization shrinkage
3. Proximal contact

Question 13

3 types of composite retainer systems:

Answer 13

1. Tofflemire with circumferential bands
2. Retainless tofflemire (absence of matrix retainer)
3. Sectional matrix

Question 14

List the steps of composite filling:

Answer 14

1. Anesthetic, isolate, select shade
2. Etch with 37% phosphoric acid for 15 s
3. Rinse (air-water spray)
4. Lightly air dry
5. Apply adhesive, lightly dry, cure (20 s)
6. Apply and cure composite in layers

Question 15

Over drying after etching and rinsing causes what?

Answer 15

Collagen fibers in dentin collapse

Increased bite sensitivity

Question 16

Describe the 2 types of adhesive systems:

Answer 16

1. Total Etch System: etch, rinse, apply bonding agent; pH=2; preferred when there are enamel margins
2. Self etch adhesive (no etch and rinse step): pH=3-5; becomes part of hybrid layer

Question 17

What adhesive do we use?

Answer 17

Optibond Solo Plus Kerr- Total etch system

Question 18

Explain the air inhibited layer

Answer 18

see slide 75 (Mikhail’s)

Question 19

Dental Composite has two phases:

Answer 19

Matrix phase (continuous)- monomer resin, initiators

Dispersed phase (discontinuous)- glass fillers, colorants

Question 20

Compare Etchants vs. Conditioners:

Answer 20

Etchants- used with composite, 35% phosphoric acid, removes smear layer and plugs, demineralizes dentin, leaves collagen rich surface with pores

Conditioners- used with GIs, polyacrylic acid, removes smear layer but leaves smear plugs intact, doesn’t demineralize dentin, cleans surface