02: Principles of Tooth Preparation

Question 1

What is the primary indication for preparation for indirect restoration?

Answer 1

Significant coronal tooth loss or destruction

Question 2

What are some causes for significant coronal tooth loss or destruction

Answer 2

Large restoration that has failed
Gross caries with significant coronal damage
Trauma resulting in damage or loss of total coronal tooth structure
Retainer for suspending pontics to replace missing teeth

Question 3

What does CVC mean?

Answer 3

Complete Veneer Crown

Question 4

What is the first step in preparation design?

Answer 4

Path of Insertion

Question 5

What does an extracoronal restoration use for retention?

Answer 5

Opposing external surfaces

Question 6

What does an intracoronal restoration use for retention?

Answer 6

Opposing internal surfaces

Question 7

What is the degree measurement of the ideal taper?

Answer 7

12 degrees

Question 8

What are two important considerations of the path of insertion?

Answer 8

Free of undercuts and appropriately aligned

Question 9

What must the path of insertion be parallel to?

Answer 9

The adjacent proximal contacts

Question 10

What happens if the path of insertion is not parallel to the proximal contacts?

Answer 10

It will be prevented from seating

Question 11

What is the purpose of tapering?

Answer 11

It provides both resistance and retention

Question 12

What are four forms of auxillary retention?

Answer 12

Box
Groove
Pin Hole
Steps

Question 13

What is the critical skill for the preparation?

Answer 13

Prepare the tooth with an ideal tapered path of placement free of undercuts.

Without damaging the adjacent tooth.

Question 14

What is something that the patient must be made aware of when they are thinking about purely cosmetic dentistry?

Answer 14

Conservation of Tooth Structure

Question 15

What crowns resulted in the least amount of lost tooth structure?

Answer 15

Ceramic veneers and Resin bonded retainers (3-30%)

Question 16

When teeth were prepared for all ceramic and metal ceramic crowns, how much coronal structure was lost?

Answer 16

63-72%

Question 17

Compared to conventional crowns, how much tooth structure was removed for porcelain laminate veneers and resin bonded prostheses?

Answer 17

1/4-1/2 the amount

Question 18

In molars that are 3-4 mm in height, exceeding a _________ degree single axial inclination angle is detrimental to overall surface area

Answer 18

10

Question 19

Students are taught a 2-5 degree taper with a 1.2-1-5 mm occlusal clearance….very hard to do. What percent of all prepared teeth meet that criteria?

Answer 19

12.7%

Question 20

What was the average taper angle?

Answer 20

9.5 degrees

Question 21

What was the average abutment height?

Answer 21

4.8-6.9 mm

Question 22

Besides boxes, grooves, and pinholes, what is another form of auxiliary retention?

Answer 22

Steps

Question 23

What type of margin placement (finish line) is better at promoting future gingival health than the other options?

Answer 23

Supragingival

Question 24

Is it more common for dental students to undertaper or overtaper?

Answer 24

Overtaper

Question 25

What is step 1 of the surveying exercise?

Answer 25

Get measurement instruments

Question 26

What is step 2 of the exercise

Answer 26

Select mandibular arch “E”

Question 27

After getting the mandibular arch “E” what is the next step

Answer 27

Affix the mandibular arch in the surveyor table

Question 28

Once the mandibular arch is affixed in the surveyor table, what is the next step?

Answer 28

Adjust the table tilt and locate the path of insertion and undercuts

Question 29

After surveying the mandibular arch on the table, what do we do?

Answer 29

Mark any undercuts with the graphite rod

Question 30

Does a CAD/CAM mill require more or less taper than a traditional crown made in a lab?

Answer 30

More (slightly)

Question 31

Lecture Quiz Question 2: Reducing the paths of removal increases……?

Answer 31

Retention

Question 32

What height tooth can get away with more taper? (Tall or Short)

Answer 32

Tall because there is more surface area

Question 33

Quiz Question 3: A prep on a tooth with a small diameter resists pivoting movements ____________ (Worse than/Better than) a prep of equal length on a tooth or larger diameter.

Answer 33

Better than

Question 34

Quiz Question 4: The resistance of this short preparation has been ________ (Improved/Reduced) by adding grooves

Answer 34

Improved

Question 35

If you have a choice, where is preferred placement of the margin (Supragingival/Subgingival)

Answer 35

Supragingival

Question 36

For marginal integrity and fit, what type of shoulder do we use (slope/bevel)

Answer 36

slope

Question 37

To help surface texture, what type of diamond bur should you try to use (Coarse/Fine)

Answer 37

Fine

Question 38

What are some results of poor marginal integrity

Answer 38

Bad fit and contours can trap bacteria and cause many more problems.