FPD Tooth Preparation

Question 1

What are the three main basic principles of tooth preparation

Answer 1

biologic
mechanical
esthetic

Question 2

The poor appearance of some metal-ceramic restorations is often due to what

Answer 2

insufficient porcelain thickness

Question 3

What four things will help conserve tooth structure during preparation

Answer 3

minimun tapered convergence angle
reduction of occlusal surface should follow the tooth anatomic planes
selection of a conservative marginal design
avoidance of unnecessary apical extension of the preparation

Question 4

Whenever possible it is imperative to place the margin where

Answer 4

supragingival

Question 5

This is the quality of the preparation that prevents the restoration from being dislodged by forces parallel to the POW

Answer 5

retention

Question 6

This is the quality of the preparation that prevents any movement of the restoration under occlusal forces

Answer 6

resistance

Question 7

What are four advantages of a supra gingival margin

Answer 7

can be easily finished
impressions are more easily made, with less potential for soft tissue damage
restoration fit can be more easily evaluated
more easily cleaned

Question 8

What are four indications of sub gingival margins

Answer 8

presence of caries, cervical lesions or restorations that extend subgingivally
need for additional retention
root sensitivity
need to hide the margin of a metal-ceramic crown for esthetic reasons; anterior restorations