Preparation Review

Question 1

How do you place a rubber dam?

Answer 1

1. Prep work
   o Punch holes in rubber
   o Check contacts for floss shredding
   - Smooth contacts if necessary
   o Mark occlusion BEFORE placing dam
2. Place clamp on tooth
3. Place dam over entire clamp
   o Can do with or without frame in place
4. Stretch dam through contacts
   o Floss between contacts
5. Invert dam
   o Delicately blow air around cervical area and push rubber into sulcus with plastic instrument
6. Ligate anterior tooth
   o Ligate with ligatures or piece of rubber dam cut and placed interproximal

Question 2

What is the most optimal method of isolation?

Answer 2

Rubber dam

Question 3

What is the anatomy of enamel rod orientation?

Answer 3

Larger diameter near surface, smaller near dentin borders

Question 4

Should you leave unsupported enamel?

Answer 4

DO NOT LEAVE UNSUPPORTED ENAMEL

Question 5

How are enamel rods and dentin in relation to eachother?

Answer 5

Enamel rods are perpendicular to long axis and radiate outward from dentin

Question 6

Where does enamel thickness vary?

Answer 6

By location and tooth types

Question 7

What percent of enamel is made of hydroxyapatite?

Answer 7

90-92% hydroxyapatite

Question 8

How would you describe enamel?

Answer 8

Strong and Brittle

Question 9

What is the largest portion of the tooth?

Answer 9

Dentin

Question 10

Where is dentin located?

Answer 10

In both the coronal and root portions of tooth

Question 11

What forms the walls of pulp chamers?

Answer 11

Dentin

Question 12

How does dentin hardness compare to enamel?

Answer 12

1/5 of enamel

Question 13

Where is dentin most hard?

Answer 13

Near DEJ than near pulp

Question 14

What percent of dentin is made of hydroxyapatite?

Answer 14

50% hydroxyapatite

Question 15

What is dentinal sensitivity?

Answer 15

Fluid movement in tubules

Question 16

Where should you aim to approach a class 3 prep and why?

Answer 16

from lingual when possible (esthetics)

Question 17

Is it accepptable to leave unsupported enamel on a class III prep?

Answer 17

May be in the facial or incisal

Question 18

What should you preserve in a class 3 prep?

Answer 18

Incisal contact

Question 19

Where is the outline form of a class 3 prep?

Answer 19

PERPENDICULAR to long axis of tooth (not lingual surface)

Question 20

What is the inciso gingival height of a class 3 prep on the lateral and central?

Answer 20

1.5 mm on lateral
2.0 mm on central

Question 21

What is the mesial distal width of a class 3 prep on the lateral and central?

Answer 21

1.0 mm on lateral
1.5 mm on central

Question 22

What contact is broken on a class 3?

Answer 22

Gingival contact

Question 23

What part of the tooth are retention points/groove added?

Answer 23

only in dentin at depth of 1⁄4 round bur

Question 24

Where are the retention points/grooves on a class 3?

Answer 24

Point is incisal
Groove is gingival

Question 25

Where is the bevel on a class 3?

Answer 25

1 mm 45 degree bevel is placed on the lingual (or facial)

Question 26

Describe the facial contact on a class 3

Answer 26

Facial contact is minimally broken so it can be seen slightly from facial

Question 27

Why is the axis of entry important on preparations?

Answer 27

For retention form to insure proper convergenct
Also important to ensure enamel rods aren’t undermined

Question 28

What is the purpose of the reverse S curve in amalgam?

Answer 28

Reverse S curve helps resist fracture of amalgam restoration by increasing the bulk of amalgam, reducing its brittleness and increasing its strength