Midterm

Question 1

What % of enamel is hydroxyapatite?

Answer 1

90-92%

Question 2

What are thin faults between enamel rod groups?

Answer 2

Enamel lamellae

Question 3

Enamel acid solubility: ?pH
Enamel + Fl2 sol: ?pH
Dentin sol: ?pH

Answer 3

Enamel: 5.5
Enamel + Fl2: 4.5
Dentin: 6.5

Question 4

What kind of dentin is closest to the odontoblast processes?

Answer 4

-Peritubular dentin

Question 5

What is reparative dentin responsive to?

Answer 5

Moderate irritant

Question 6

What happens to the peritubular dentin in sclerotic dentin?

Answer 6

it widens and fills with calcified material

Question 7

What % of dentin is hydroxyapatite?

Answer 7

50% and 1/5 hardness of enamel

Question 8

What are the 5 objectives of tooth preparation?

RREPR

Answer 8

• Remove defects
• Resist fracture when chewing
• Extend restoration as conservatively as possible
• Provide necessary protection to pulp
• Restore esthetics and function

Question 9

Where is it acceptable to leave residual caries?

Answer 9

-as affected dentin near the pulp

Question 10

What do good pulpal and gingival floors and walls do?

Answer 10

• stabilizing seats

- distribute stress

Question 11

Types of edges/line angles?

Answer 11

• Bevel
• 90 degree
• chamfer

Question 12

Class 1 Prep surfaces

Answer 12

occlusal

Question 13

Class 2 Prep surfaces

Answer 13

proximal

Question 14

Class 3 prep surfaces

Answer 14

proximal of incisors and canines

Question 15

Class 4 prep surfaces

Answer 15

proximal and incisal of anteriors

Question 16

Class 5 prep surfaces

Answer 16

cervical 1/3 smooth surfaces

Question 17

Class 6 prep surfaces

Answer 17

incisal edge or cusp

Question 18

Where do you NOT want occlusion on a prep?

Answer 18

On the margins (edges of prep)

Question 19

When do you connect two preps?

Answer 19

When they are less than 0.5 mm apart

Question 20

How deep should the axial wall depth be on class 2 preps?

Answer 20

0.2-0.8 mm INTO THE DENTIN

Question 21

In an enameloplasty, what is the maximum amount of enamel that should be removed?

Answer 21

no more than 1/3 of total enamel thickness

Question 22

Amalgam preps should be at least ______ mm deep

Answer 22

1.5 mm

Question 23

Gold preps should be at least ______ mm deep

Answer 23

1-2 mm

Question 24

Porcelain preps should be at least ______ mm deep.

Answer 24

2 mm

Question 25

What is the purpose of the dovetail?

Answer 25

prevents tipping and proximal displacement