Post and Core

Question 1

a core restoration is also known as:

Answer 1

a foundation

Question 2

what is the purpose of a core resoration

Answer 2

replace missing tooth structure prior to crown preparation

Question 3

posts are also known as:

Answer 3

dowels

Question 4

what is a dowel

Answer 4

a post, usually made of metal that is fitted into a prepared root canal of a natural tooth. when combined with an artificial crown or core, it provides retention and resistance for the restoration

Question 5

what is the function of a post

Answer 5

• anchor the core material with a stable post
• restore missing tooth structure
• reinforce the tooth-restoration

Question 6

which endo teeth should receive a post

Answer 6

• when there is not adequate tooth structure to retain a core
• most FPD and RPD abutment teeth

Question 7

when is there not adequate tooth structure to retain a core

Answer 7

• often single rooted teeth because the anatomy of the pulp chamber does not offer mechanical retention
• teeth that have lost more than 50% of the coronal tooth structure

Question 8

what materials can be used for a post

Answer 8

• custom post
• prefab post

Question 9

what materials can a pre fab post be made of

Answer 9

• metal post
• fiber post

Question 10

what is another name for custom posts

Answer 10

cast post and cores

Question 11

custom posts are usually cast in ______

Answer 11

type III gold

Question 12

custom posts are often ________ in shape

Answer 12

tapered and ovoid in cross section (built in anti-rotation)

Question 13

custom posts rely mostly on _____ for retention

Answer 13

cement

Question 14

what percentage of clinicians use a custom post

Answer 14

less than 10%

Question 15

custom posts are the only option when:

Answer 15

the crown and post have different angulations

Question 16

what are the alloys for pre fab posts made of

Answer 16

titanium or stainless steel

Question 17

describe the shape of pre fab posts

Answer 17

• mostly parallel walled (greater retention) and round shaped in cross section (does not provide anti rotation)

Question 18

which posts have greater versatility: pre fab or custom

Answer 18

pre fab

Question 19

how do you begin a post treatment

Answer 19

use isolation prior to beginning

Question 20

how do you create a post space

Answer 20

-gutta percha removal technique
- peeso reamers
-gates glidden drills
- hot instruments

Question 21

gutta percha can be removed either:

Answer 21

immediately or delayed

Question 22

what is the ferrule effect

Answer 22

a minimum of 2mm vertical axial wall circumferentially must be present

Question 23

what are the types of cross section post shape

Answer 23

• tapered post (most custom posts)
  -parallel wall post (most pre fab)

Question 24

the most retention would be provided with a _____ what shape post?

Answer 24

parallel walled

Question 25

describe anti rotation in cast posts

Answer 25

built in (oval in cross section)

Question 26

describe anti rotation in pre fab posts

Answer 26

lack of anti rotation (round in cross section)

Question 27

how is an amalgam core used

Answer 27

-cement pre fab post in the canal - condensed amalgam around the post

Question 28

critical to have access to condense amalgam _____

Answer 28

around the post

Question 29

_______ dictates post orientation

Answer 29

root canal morphology

Question 30

describe the retention between post retained amalgam and cast post and core

Answer 30

similar retention

Question 31

the greatest the post length, the _______ the retention of the post

Answer 31

greater

Question 32

a ______ can cause root fracture

Answer 32

short post

Question 33

the post should be at least as long as:

Answer 33

the length of the crown

Question 34

retain _______ of apical gutta percha to preserve the seal of the endo tx

Answer 34

4-5mm

Question 35

the diameter of the post should not be greater than _______ of the tooth/root diameter

Answer 35

1/3

Question 36

choosing a post is usually based on the optimum _______

Answer 36

diameter

Question 37

most of the time _______ per tooth is adequate

Answer 37

one post

Question 38

what are the fiber reinforced post materials

Answer 38

silica fiber -glass fiber - quartz fiber posts

Question 39

what are the names of the fiber reinforced posts

Answer 39

- parapost fiber white and fiber lux - dentflex - luscent anchors - fibrekor - FRC postec - DT light post - aestetic plus

Question 40

what is the main advantage of fiber reinforced posts

Answer 40

better esthetics

Question 41

what is the main difference of fiber reinforced posts from metal posts

Answer 41

modulus of elasticity similar to dentin (however the modulus decreases over time and more critically in the presence of moisture)

Question 42

what are the failures of fiber reinforced posts

Answer 42

- less root fractures than metal posts, fracture usually occurs in the coronal part of the post itself or debonding of the post occurs - failure rates range from 0-32.2%

Question 43

what are most of the fiber reinforced post failures from

Answer 43

the post becomes debonded

Question 44

what is the indication for use of fiber reinforced posts

Answer 44

only teeth that have several dentinal walls remaining

Question 45

what is the main clinical consideration for fiber reinforced posts

Answer 45

the majority of failures with these posts occur on teeth that have little natural tooth structure remaining

Question 46

describe ceramic posts

Answer 46

- good esthetics - very rigid (high modulus of elasticity) - high rates of root fracture

Question 47

what are posts cemented with

Answer 47

- zinc phosphate cement - resin cements - glass ionomer cements - modified resin glass ionomer cements

Question 48

canal should be cleaned with_____ prior to post cementation

Answer 48

phosphoric acid

Question 49

what is the step by step clinical procedure for post tx

Answer 49

- isolate the tooth with rubber dam - remove GP (use peeso reamer #2, #3. avoid #5 and #6), evaluate with radiographs periodically for angulation and length (post should be as long as possible and retain 4-5mm apical GP) - post diameter should not exceed 1/3 root diameter - for prefab posts the final drill should be the drill that corresponds with the correct post diameter - for prefab posts the length should be adjusted so that the head of the post is at the top of the core - cement post (for prefab posts remove cement from most coronal part of canal to allow core material to help with anti rotation) - 2mm ferrule (natural tooth structural) circumferentially is critical for longevity regardless of post used

Question 50

amalgam is condensed into:

Answer 50

the pulp chamber and 2-3mm into the pulp canal

Question 51

if the pulp chamber is 4mm in height:

Answer 51

sufficient retention from pulp chamber alone

Question 52

amalgam radicular core benefits:

Answer 52

reduced number of visits/reduces cost

Question 53

endo access results in:

Answer 53

reduced tooth fracture

Question 54

what other factors affect strength

Answer 54

- previous/existing caries/restorations - amount of root surrounded by alveolar bone

Question 55

when do crowns on endo treated teeth not improve success rates

Answer 55

anterior teeth

Question 56

when do crowns of endo treated teeth improve success rates

Answer 56

in posterior teeth

Question 57

endo treated teeth without crowns lost at _____ the rate of those with crowns

Answer 57

6 times

Question 58

teeth with 2 proximal contacts had ______ survival than teeth with 1 or no proximal contacts

Answer 58

significantly longer

Question 59

2nd molars showed _______ compared to all other teeth

Answer 59

significantly reduced longevity