1 Fundamentals

Question 1

Enamel:___% inorganic hydroxyapatite mineral by wgt. __% volume

Answer 1

96% by wgt…86% vol

Question 2

Enamel: Small organic matrix of two types of glycoproteins __________ & __________ in intercrystalline spaces and in a network of micropores opening to the external surface.

Answer 2

amelogenins & enamelins

Question 3

What defines the COLOR of teeth?

Answer 3

Enamel Thickness and the color of the underlying DENTIN

Question 4

What is the narrow space around 3/4 of each Enamel Rod and is KEYHOLE shaped?

Answer 4

Rod Sheath

Question 5

What are the two structural units of Enamel?

Answer 5

1.Cylindrical Enamel Rods and 2.Interrods (both containing hydroxyapatite crystals)

Question 6

*What are the two types of dentin?

Answer 6

*InterTubular Dentin and Peritubular Dentin

Question 7

*Which dentin type is the STRUCTURAL component of the hydroxyapatite-embedded collagen matrix and the BULK of the dentin?

Answer 7

*InterTubular Dentin

Question 8

*Which Dentin is LIMITED to the lining of the tubular walls and has LITTLE organic matrix packed DENSELY with apitie crystals?

Answer 8

*Peritubular Dentin

Question 9

*Which dentin type increases with age?

Answer 9

*Peritubular dentin

Question 10

*Which atomic building bond is the strongest AND simplest where atoms SHARE electrons?

Answer 10

*Covalent Bonds

Question 11

Rank the strength of these individual bonds from Strongest to Weakest: Ionic, Metallic, Covalent

Answer 11

Srongest: Covalent—->Ionic—–>Metalic

Question 12

What am I? Since ions are surrounded by non-directional electrostatic fields, it is possible for + and – ions to find positional arrangements that are mutually beneficial and lowers the energy. Ions can form a regular, 3-D network.

Answer 12

An IONIC SOLID! Building blocks of Ceramics!

Question 13

What am I? Similar arrangement to ionic solids except that there is no strong electrostatic attraction between atoms. Held together by the cloud of electrons.

Answer 13

Metallic Solids!

Question 14

What am I? Some atom of the same elements can join (C, Si, Ge). They have directional bonds that limit the possible arrangement of the atoms. The shared electrons result in filled orbits = stable molecules. Rare occurrences -diamonds.

Answer 14

Covalent Solids!

Question 15

What did Dr. Cramer consider Van der Waal and hydrogen bonds to be categorized as?

Answer 15

Secondary Bonds

Question 16

What am I? Some molecules can be solid at room temp. If they are long enough the dipole-dipole inter- actions can bond molecules together. Low bond strength means low melting temps. Eg: WAXES!

Answer 16

Molecular Solids

Question 17

What are the two possibilities for arrangement of solids?

Answer 17

Crystalline and Amorphous

Question 18

CERAMICS-what type of bonds and what is the arrangement of solids?

Answer 18

Ionic Bonds….Crystalline and Amorphous

Question 19

METALS-what type of bonds (DONT get that wrong) and what arrangement of solids?

Answer 19

Metallic bonds….Crystalline

Question 20

POLYMERS-what type of bonds? How is it like wax?

Answer 20

Covalent and Secondary bonds…like wax because polymers are molecular solids

Question 21

*What property of materials encompasses toxicity and sensitivity reactions that occur locally or systemically within associated tissues?`

Answer 21

*Biological Property

Question 22

What is this phenomenon? Atoms or molecules at the surface of liquids or solids differ from those in the bulk creating an inward attraction toward the bulk thus adsorbing ambient atoms or molecules.

Answer 22

Surface Properties

Question 23

*What is this describing?: A low surface energy liquid will readily spread over a high surface energy substrate.

Answer 23

*Surface energy

Question 24

*What is this describing?: The measure of the affinity of a liquid for a solid as indicated by the spreading of a drop.

Answer 24

*Wettability

Question 25

What is perfect wettability?

Answer 25

A contact angle of 0 degrees!

Question 26

*Which form of sorption occurs when dissimilar substances in intimate contact with the surfaces of a solid = ADHERE?

Answer 26

*Adsorption

Question 27

*high energy surfaces will _____ molecules more readily than low energy surfaces

Answer 27

*ADsorb

Question 28

*Which form of sorption is the uptake of a liquid by a bulk solid?

Answer 28

*Absorption

Question 29

*The substance absorbed _______ into the

solid material

Answer 29

*Diffuses…his example-nasty ass dentures that have absorbed chemicals and food particles and now smell bad

Question 30

*What is the most important biocompatability test?

Answer 30

*The Usage Test

Question 31

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

Answer 31

*Usage Tests

Question 32

What is the Advantage to Usage Tests for Biocompatability?

Answer 32

Relevance to use the material is ASSURED

Question 33

*What are the 5 disadvantages to usage tests?

Answer 33

*1.Expensive 2.Time 3.Legal/Ethical Issues 4.Control 5.Interpretation

Question 34

*_________ – materials may not bond with sufficient strength to resist contraction on polymerization, wear, thermal cycling

Answer 34

*MicroLeakage

Question 35

*_____ between tooth and restoration allows influx of materials that may irritate the pulp.

Answer 35

*Gap

Question 36

_____ ______ – organic and inorganic debris

forms dentinal plugs in tubules that renders them impermeable. Must be removed for strong bonds.

Answer 36

Smear Layer

Question 37

*What is the MINIMAL REMAINING DENTINAL THICKNESS (RDT)? How much leakage can you reduce at this thickness? What is the thickness for 100% reduction in leakage?

Answer 37

*0.5mm RDT…reduce 75% of leakage..2.0mm=100%reduction in micoleakage

Question 38

What about amalgam Seals the bond onto the prep?

Answer 38

Corrosion!

Question 39

Which material is unable to diffuse through dentin?

Answer 39

Glass Ionomers