Rest ops for root filled teeth

Question 1

What are the 2 main options when a patient has a tooth with pulpal disease

Answer 1

1. Extract
2. Consider endodontic treatment- pre-op assessment

Question 2

What can be the outcomes of a pre-op assessment when considering endodontic treatment on a tooth

Answer 2

1. insufficient tooth tissue for strength or to create ferrule
2. sufficient tooth tissue for direct restoration
3. greater tooth loss but ferrule possible

Question 3

What are the options for a tooth that has insufficient tooth tissue for strength or to create ferrule

Answer 3

overdenture abutment
extract

Question 4

What is an overdenture

Answer 4

a denture that goes on top of badly broken teeth

Question 5

what is the ferrule of a tooth

what is its role

Answer 5

the portion of the crown that encircles the remaining dentine

binds to remaining tooth, prevents root from fracturing and provides resistance

pic

Question 6

what should the height of the ferrule be
what should the width of the ferrule be
how much of an angle should the ferrule be encircling the tooth

Answer 6

atleast 2mm
atleast 1mm
360 degrees, but dependant on tooth as some surfaces are important than the other

Question 7

what is the ferrule effect

Answer 7

during occlusion, the encircling of the crown on top of the sound dentine will transmit the forces in a more favourable way to the PDL and the bone, preventing fractures and dislodgement

Question 8

What are the 3 sections of an assessment of a root filled tooth

Answer 8

endodontic assessment
periodontal assessment
coronal tissue assessment

Question 9

Explain how to carry out a coronal tissue assessment

Answer 9

1. remove existing restorations to evaluate remaining tooth tissue
   - assess quality of remaining healthy tooth tissue
   - height minimum 1.5-2mm for ferrule
   - thickness of tooth tissue
   - position of remaining healthy tooth tissue- B/L/M/D
2. aesthetics
   - tooth/root discolouration
   - tooth shape
3. occlusion
   - is the tooth in occlusion
   - does the tooth contribute to lateral or protrusive guidance
   - will the forces on the tooth be low or high during function

Question 10

what are the 4 rationale principles of restoring root filled teeth

Answer 10

1. to provide a biological seal (coronal seal) to prevent infection of the root canal system
2. to protect remaining tooth tissue
3. to maintain occlusal stability and proximal contacts to prevent over eruption or drifting
4. to restore function

Question 11

What is the option for when a tooth has pulpal disease and sufficient tooth tissue for direct restoration

Answer 11

restore with composite (or amalgam) with weak cusps reduce and onlayed

Question 12

What is the option for when a tooth has pulpal disease and greater tooth loss but a ferrule is possible

Answer 12

direct amalgam or composite core
then, preparation for indirect restoration (crown or onlay)

Question 13

What do you require for a tooth with pulpal disease, has greater tooth loss but a ferrule is possible and the core requires additional retention and support

Answer 13

a post

Question 14

what type of core is used when the tooth requires retention

Answer 14

a composite nayyar-type core

Question 15

what type of post is used when the tooth requires more retention

Answer 15

prefabricated post

Question 16

what type of post is used when the tooth requires most retention

Answer 16

cast post and core

Question 17

to place a direct restoration, after you have finished your root canal tx, what must you do

Answer 17

remove gp until level with CEJ
seal gp inside the canal

Question 18

what can be used to seal the gp in the canals

Answer 18

rmgic

Question 19

describe the Nayyar type core (corono-radicular dowel)

Answer 19

doesn’t use a post
relies on the shape of the root canal to go in to different root canals and gain retention (retention from coronal and radicular tooth tissue)
2-4mm GP removed from each canal using gates glidden

pic

Question 20

what are the 2 main types of posts

Answer 20

prefabricated post (chair-side)
cast post and core (lab involved)

Question 21

What is the only use of posts

Answer 21

to retain core

Question 22

what are some issues with posts

Answer 22

weaken teeth
can cause perforations

Question 23

what type of posts should you use

Answer 23

parallel, tapered, non metal, ready made/custom made post

Question 24

what types of posts should you avoid and why

Answer 24

threaded posts as they induce stress on the canals and can lead to fractures

Question 25

what length should the post be

Answer 25

post length at least equal to cornal length, whilst still keeping enough apical seal

Question 26

what is important when doing a post

Answer 26

the presence of a ferrule of 1.5-2mm is more important in fracture resistance than the post design or type

Question 27

what 3 materials can a prefabricated post be made from

Answer 27

stainless steel titanium fibre-reinforced composite 'fibre posts'

Question 28

explain how to fit a prefabricated post

Answer 28

1. use GG burs in order to remove GP- follow canal direction to desired length 2. use parapost drills to prepare post channel 3. try in matching fibre posts, ensure stability and fit to desired length (may need to move up drill size be aware of canal/root width)

Question 29

Advantages of fibre posts

Answer 29

1. aesthetics- metal free 2. bond with dual and self cure resin cements and composite core material - benefits of adhesive techniques 3. flexural properties closer to those of dentine 4. can be removed for revision of endodontic treatment 5. claimed to reinforce tooth (evidence hasn't confirmed) 6. post more likely to fracture than root, decementation is commonest mode of failure but retrievable failures

Question 30

how do you make a cast post

Answer 30

1. post channel is prepared in the tooth 2. then a plastic impression post is used along with silicone impression material to record the shape of the post space within the canal 3. a post is cast along with the core in the lab 4. this single unit is then cemented into the tooth at a further visit

Question 31

for when a cast post is being made, what is needed between appts

Answer 31

a temporary post and core

Question 32

What are the 3 guidelines for post length

Answer 32

1. As much as post as possible in root which is supported in bone 2. Post length in bone at least as much as that above the boney crest level 3. 4-5mm apical GP remaining

Question 33

What are the 2 guidelines for post stress distribution

Answer 33

1. Force transmitted to core and onto post 2. Force transmitted to dentine

Question 34

What are the 3 criteria for the post diameter

Answer 34

1. Retain as much coronal and radicular dentine as possible 2. Narrower diameter posts preserve more tooth structure and reduce risk of root fracture 3. Too narrow a post may bend or fracture

Question 35

2 advantages of cast post and core

Answer 35

Can go subgingivally Good if oval canal

Question 36

3 disadvantages of cast post and core

Answer 36

1. Extra clinical visit 2. Greater likelihood of discrepancies introduced by impressions, casting models, casting metal 3. Temporisation difficult coronal seal

Question 37

4 advantages of prefabricated post

Answer 37

+ Immediate coronal seal + Crown prep can be done at same visit + Better aesthetics (fibre post) + Reduced number of stages therefore reduce discrepancies

Question 38

1 disadvantage of prefabricated post

Answer 38

- Core takes time to build

Question 39

3 options for cuspal protection

Answer 39

* Extra-coronal Restorations * Inlays/ Onlays * Full coverage crowns

Question 40

3 guidelines for occlusion

Answer 40

* Post-crowned canines should not provide canine guidance - planned change to group function needed * Post-crowned posterior teeth - ICP contact only * Post-crowned anterior teeth - incisal guidance should be shared across all anterior teeth

Question 41

4 ways root filled teeth can fail

Answer 41

1. Perforations 2. Poor coronal seal- reinfection of the root canal and apical pathology 3. Root fracture 4. Fractured post