post and core

Question 1

What type of post is best for retention?

Answer 1

Active>passive and parallel>tapered

Question 2

Cast P+C are made from what type of gold?

Answer 2

Type 3 and noble alloys

Question 3

What materials are prefab P+C made out of?

Answer 3

SS, titanium, ceramic, fiber(carbon, glass, quartz), brass, zirconia

Question 4

Rate how retrievable posts are from more retrievable to least.

Answer 4

Fiber > Metal > ceramiz/zirconia/titanium

Question 5

What is a significant weakness of retrospective studies?

Answer 5

It’s probably missing important pieces of info bc dentists don’t record EVERY little detail.

Question 6

What are KOLs (Key opinion leaders)

Answer 6

recruited and paid to research product/publish results

Question 7

Gold standard trials must be:

Answer 7

Randomized, controlled (txs are assigned randomly), and blinded (evaluators don’t know which pt received what tx.

Question 8

Besides for the post, other factors that contribute to the success of P+C?

Answer 8

tooth type, post length, ferrule effect, cement used, DENTIN left

Question 9

What type of tooth would be good with a 1. Parapost? 2. Cast? 3. Screw post?

Answer 9

1. Parapost - long, straight, circular canals in anterior
2. Cast= short, curved, ovoid canals in molars
3. Screw = very short canals

Question 10

When do you definitely need a P+C?

Answer 10

loss of 2 cusps<2mm ferrule

Question 11

KOLs may blame failure on ____ instead of post?

Answer 11

cement or endo

Question 12

What are the risks with post placement?

Answer 12

Perforation or loss of apical seal, inc risk of root fracture (esp if post is too large)

Question 13

What makes for a good prognosis?

Answer 13

1. Adequate ferrule: Best predictor of success
2. Adequate post length
3. Cuspal coverage for posteriors
4. Use of retrievable posts

Question 14

Things that make failure more likely?

Answer 14

1. Threaded posts
2. inadequate dentin/ferrule height
3. use of post that are difficult to retrieve
4. use of post in multi-rooted molar

Question 15

Types of failure?

Answer 15

1. loss of retention (of crown, core, and/or post)
2. PARL or caries
3. fractured crown or root
4. Iatrogenic: post too short, perforate/weaken root

Question 16

Options for gutta percha removal?

Answer 16

Risk of perforation or loss of apical seal. Lowest risk is a hot instrument or chemicals

Question 17

Highest risk approach to remove gutta percha

Answer 17

mechanical removal with end cutting burs; para-post drills; Minimized risk = Gates-Glidden burs

Question 18

What is the absolute minimum or GP that must remain in canal?

Answer 18

Minimum of 4 mm but 5 is preferred AND 1/2 - 2/3rds the length of root in bone + length equal to length of crown

Question 19

What is the minimum of denting all around at apex?

Answer 19

1 mm. The post should be equal to about 1/3rd the diameter of root

Question 20

While paraposts are very popular, ______ types of posts are also needed and fit more canals typically?

Answer 20

Tapered: they require less tooth structure removal.

Question 21

Tapered posts may have a ____ effect. This is minimized by having ________?

Answer 21

wedging; adequate ferrule and vertical stop on coronal tooth structure

Question 22

Post length is good for what two things?

Answer 22

retention AND Stress distribution

Question 23

1. _______ portion acts as lever arm

2. _______ portion distrubutes stress over area of post-root contact.

Answer 23

1. Coronal 2. Radicular

With inc root length, coronal portion is at mechanical disadvantage so stress is over a larger area

Question 24

Examples of less rigid/more rigid posts?

Answer 24

Less: carbon, quartz, glass
More: titanium (non-corrosive/weak), SS (corrosive), Cast metals, noble alloys

Question 25

Rigid advantages/disadvantages?

Answer 25

Resists lateral forces better but has higher incidence of root fracture (1.7%)

Question 26

Flexible pro/cons

Answer 26

deform during fxn = loss of seal and leakage BUT 0% failure (according to study that seems bias)

Question 27

How many pins do you need in your buildup?

Answer 27

Fewest possible: 1 per line angle. Molars = 1 per cusp missing and premolars = 2 per missing cusp

Question 28

Position of pins?

Answer 28

line angles; 3-4 mm between pins, corners are safest area for pin placement.

Question 29

Rule of 2s

Answer 29

2 mm depth of pin hole; 2X diameter = position inside DEJ; 2mm length above dentin; 2mm of amalgam covering pin

Question 30

Slots are useful when?

Answer 30

There isn’t enough room for pin and amalgam