ENDO - Restoration Options for Root-Filled Teeth

Question 1

what is generally the two options of a patient with pulpal disease?

Answer 1

extract
RCT

Question 2

what if you want to do a RCT, but there is insufficient tooth tissue for strength or to create a ferrule?

Answer 2

extract and can put an over denture abutment on it

Question 3

what is a ferrule? what is it used for?

Answer 3

part of the crown that goes around the remaining dentine
- helps to retain a tooth root against forces

Question 4

define the ferrule effect.

Answer 4

cementing a ferrule or 360º metal around a tooth, preventing independent flexure of tooth structures

Question 5

what is the role of a ferrule?

Answer 5

• to bind to the remaining tooth
• prevent root fracture
• provide resistance from the crown dislodging in function

Question 6

what should be the height and width of the ferrule?

Answer 6

2mm x 1mm

Question 7

which tooth is a ferrule most effective?

Answer 7

upper incisor as it supports occlusive forces

Question 8

what happens if you put a crown on a badly worn down tooth and have no ferrule?

Answer 8

it will not support the occlusive forces
- leads to root fractures

Question 9

What are the 3 Basic Areas to Assess of Root Filled Teeth Requiring Endo?

Answer 9

Endodontic Assessment
Periodontal Assessment
Coronal Tissue Assessment

Question 10

what comes under coronal tissue assessment?

Answer 10

1. remove any existing restorations and decay
2. evaluate remaining tooth tissue
   - thickness
   - all positions of tissue
   - min height for ferrule
3. aesthetics
   - discolouration and shape
4. occlusion
   - lateral or protrusive guidance
   - how large are forces during function

Question 11

What are the 4 Principles of Restoring Root Filled Teeth?

Answer 11

• provide a coronal biological seal to prevent re-infection of the root canal system
• protect remaining tooth structure
• maintain occlusal stability and proximal contact to prevent over eruption or drifting
• restore function

Question 12

what do you use to restore the tooth with sufficient tooth tissue?

Answer 12

amalgam or composite with a RMGIC base to seal

Question 13

what do you use to restore the tooth with great tooth loss but yet a ferrule is still possible.

Answer 13

a direct amalgam or composite core
- then prepare for crown or onlay

Question 14

As though a root canal is harder and harder to fill, what techniques are used?

Answer 14

• composite
• composite Nayyar type core
• prefabricated post
• cast post and core

Question 15

What is a Nayyer Type Core? How is it done?

Answer 15

relies on shape of root canal for retention
- doesn’t need a post

do procedure as normal up to obturation
- use gates-glidden drill
- remove 2-4mm of GP
- place thin layer or RMGIC
- condense amalgam or composite into root canals
- finish

Question 16

Why may you need posts in RCT? What is one large disadvantage..

Answer 16

• retain the core

but can weaken the teeth and cause perforations

Question 17

2 Types of Posts.

Answer 17

prefabricated post
cast post and core

Question 18

Describe a Pre-Fabricated Post and types.

Answer 18

it is done chair side
- a post channel is prepared in the tooth and post is immediately cemented

• stainless steel
• titanium
• fibre-reinforced composites = fibre posts

Question 19

Describe the Technique in Installing a Pre-Fabricated Post.

Answer 19

• use gates-glidden bur to remove GP
• use parapost drills - prepare post channel
• see if fibre post matches length and stability

Question 20

Give 6 Advantages to Fibre Posts

Answer 20

aesthetic
metal free
bonds with resin and composite
flexural properties similar to dentine
can be removed
post is more likely to fracture than the root

Question 21

Describe the Cast Post and Installation

Answer 21

• involves a lab stage
• post channel is prepared
• plastic impression post w/ silicone
• records shape of post shape
• post is cast with the core in the lab
• cemented into the tooth at a further visit
• temp post and core is needed between appointments

Question 22

How long should a post be?

Answer 22

4-5mm apical GP should remain
- as much post as possible in the root which can be supported

Question 23

What would be a Ideal Situation for stress distribution for a post?

Answer 23

• force transmitted to core and post
• transmits to dentine
• transmits to PDL and bone

Question 24

What would be a Poor Situation for stress distribution for a post?

Answer 24

• force transmits to core and post
• transmits to dentine
• unsupported by PDL and bone

Question 25

What should be the diameter for a post?

Answer 25

• narrower = preserve more tooth structure and reduce risk of root fracture
• too narrow = post may bend or fracture

Question 26

4 Advantages of Pre-fabricated Post

Answer 26

• immediate coronal seal
• done at the same visit
• better aesthetics
• less stages = less discrepancies

Question 27

1 Disadvantage of a Pre-Fabricated Post.

Answer 27

the core takes time to build

Question 28

2 Advantages of a Cast Post and Core

Answer 28

• can go subgingivally
• good if the canal is oval

Question 29

3 Disadvantages of a Cast Post and Core

Answer 29

• extra visits
• greater chance of discrepancies - impressions etc
• temporary seal difficulties

Question 30

Which Teeth are at Greater Risk of Fracture?

Answer 30

posterior

Question 31

how can a tooth be protected from fracture?

Answer 31

cuspal protection or full coverage restoration

e.g. extra-coronal restorations, inlays, onlays, full coverage crowns

Question 32

In terms of Occlusion, what are the Guidelines for Post Crowns for Anterior, Posterior and Canines?

Answer 32

Anterior
- incised guidance should be shared across all ant

Posterior
- ICP contact point only

Canines
- should not provide canine guidance, should be group function

Question 33

How can the Restoration of a Root Filled Tooth Fail? (4)

Answer 33

• Perforation
• Poor Coronal Seal - reinfection
• Root Fracture
• Fractured Post