Intro

Question 1

What is a rod sheath?

Answer 1

Narrow space around 3/4 of each enamel rod. Keyhole shape.

Question 2

What two structural units make up enamel?

Answer 2

Enamel rods and interrod enamel (both contain hydroxyapatite crystals)

Question 3

What is intertubular dentin?

Answer 3

Material that runs in b/w the dentinal tubules - makes up the bulk of the dentin. It is the structural component of the hydroxyapatite-embedded collagen matrix

Question 4

What is peritubular dentin?

Answer 4

Dentin that surrounds the dentinal tubules.Limited to the lining of the tubular walls - little organic matrix densely packed w/ apatite crystals.

Question 5

What happens to the peritubular dentin with age?

Answer 5

Increases w/ age and decreases the lumen size of the tubule

Question 6

What are the three primary bonds?

Answer 6

Covalent, Ionic, and Metallic

Question 7

Which bond is the strongest and simplest?

Answer 7

Covalent

Question 8

Ionic bonds are frequent in what materials?

Answer 8

Ceramics

Question 9

Covalent bonds are commonly seen in what materials?

Answer 9

Polymers

Question 10

Which bond has electrons that move freely thru the solid?

Answer 10

Metallic bond

Question 11

Biological properties of materials have what implications?

Answer 11

Toxicity and sensitivity reactions that occur locally or systemically w/in associated tissues

Question 12

How does a low surface energy liquid spread over a high surface energy substrate?

Answer 12

Spreads readily

Question 13

What is wettability?

Answer 13

The measure of the affinity of a liquid for a solid as indicated by the spreading of a drop - how a material will flow over the surface of a tooth

Question 14

What is the main difference w/ high surface energy vs low surface energy?

Answer 14

High surface energy will attract things to it. Low surface energy will not. Ex - dentin or enamel has high surface energy

Question 15

How does high surface energy surface affect wettability?

Answer 15

Keeps a drop balled up and wettability is low

Question 16

What is sorption?

Answer 16

It’s what happens on the surface of the tooth - adsorption and absorption

Question 17

What is adsorption?

Answer 17

dissimilar substances in intimate contact w/ the surfaces of a solid

Question 18

How do high energy surfaces affect adsorption?

Answer 18

High energy surfaces will adsorb molecules more readily than low energy surfaces

Question 19

What is the difference b/w adsorption and absorption?

Answer 19

Adsorption is liquid sticking to the surface of a material. While absorption is liquid taken up into the body of a material

Question 20

What is absorption?

Answer 20

Uptake of a liquid by a bulk solid. The substance absorbed diffuses into the solid material. Acrylics of dentures can absorb liquids

Question 21

What is a usage test?

Answer 21

material is placed in a situation identical to its intended clinical use. In animals or humans (clinical trials)

Question 22

Microleakage is a big deal for what kind of materials?

Answer 22

Restorative materials

Question 23

What is microleakage?

Answer 23

Materials may not bond w/ sufficient strength to resist contraction on polymerization, wear, thermal cycling

Question 24

What does microleakage cause?

Answer 24

A gap b/w tooth and restorative material

Question 25

What is the biggest cause of post-operative sensitivity?

Answer 25

Microleakage that causes a gap b/w tooth and restoration and allows influx of materials that may irritate the pulp

Question 26

What is most important for pulp protection?

Answer 26

.5mm of remaining dentinal thickness (RDT)