Tooth wear and Indirect Restorations

Question 1

When are fixed restorations possible in tooth wear cases?

Answer 1

If 50% of structure still present above gingival margin
- Can consider crown lengthening surgery if this is not available

Question 2

What are the issues with tooth preparation in wear cases?

Answer 2

Lack of occluso-gingival height (occlusal surface to top of gingival margin)
-> Little room for retention and resistance form

Lack of occlusal and palatal space

Severely compromised teeth

Question 3

What can be done to maximise retention and resistance when placing indirect restorations on worn teeth?

Answer 3

Materials
Grooves/Inlays- reduce radiation of rotation
Ferrule
Parallel preps
Margins & occluding surfaces
Cores
Electrosurgery
Surgical Crown lengthening

Question 4

What materials can be used for indirect restorations in tooth wear cases?

Answer 4

Metal ceramic
-> metal on biting surfaces
-> porcelain on aesthetic areas (may only be some of the cusp)

Question 5

How are grooves prepped?

Answer 5

Cut down long axis of the tooth
-> parallel with path of insertion and removal
-> tell technician you want metal fitting surface of crown to go into groove

Question 6

How can adding an inlay style prep to your crown prep be beneficial?

Answer 6

Walls give retention
-> good if high aesthetic demand

Question 7

Why is it important to check radiographs before cutting grooves and inlays?

Answer 7

To check for position of pulp

Question 8

What is the issue with no ferrule?

Answer 8

It is unlikely that the tooth will be restorable with crowns
-> lack of resistance form

Question 9

What can be used to help us assess restorability of teeth?

Answer 9

Dental Practicality Index

Question 10

What are the positives of parallel preps?

Answer 10

Aids retention of crown in shortened teeth

Question 11

What are the issues with parallel preps?

Answer 11

Technician has less space to develop aesthetics leading to opaque crowns

-> inform patient that aesthetic compromise is likely

Question 12

What can be done of worn teeth have large sub gingival restorations?

Answer 12

• Put core material in to restore deep cavity
• Electrosurgery- remove gum to ensure accuracy of impression and create ferrule
• Palatal groove- may be a better position in relation to pulp

Question 13

What are the advantages of metal palatal surfaces in anterior teeth?

Answer 13

Opposing arch bites on metal

Useful in erosion cases

Minimal prep required due to thin metal

Question 14

What are the advantages of a curved prep for porcelain?

Answer 14

Prevents debonding and crack propagation
-> esp helpful in wear cases where there is increased load

Question 15

How can reinforced composite be helpful when restoring near the gingival margin?

Answer 15

Autocured- so will set in these conditions

Question 16

What is a Nayyar core?

Answer 16

Amalgam core where GP is removed from canals at the coronal part and packed with amalgam

Question 17

Why are metal margins around the bottom of posterior teeth preferred?

Answer 17

Less is removed from tooth

Less chance of going close to pulp

Question 18

When is surgical crown lengthening considered in tooth wear cases?

Answer 18

After every other option has been exhausted and adhesive dentistry had failed

Question 19

How is crown lengthening achieved?

Answer 19

Remove bone around tooth to increase amount of tooth in mouth and OG height
-> Retract flap, remove bone and excess gum and suture gum more apically
(Co-pack can help healing)

Question 20

How long does it take for gingival margin to stabilise following surgical crown lengthening?

Answer 20

3 months

Question 21

What can be placed while the gingival margin is stabilising following SCL?

Answer 21

Temporary crowns to cover over exposed root cementum and prevent sensitivity

Question 22

What can be added to crowns to make them look more natural?

Answer 22

Features of tooth wear

Question 23

Why may a dentist choose to have metal extend from biting surface partially onto buccal surface?

Answer 23

Can ensure that heavy contact on lateral excursions is less likely to fracture porcelain

Question 24

What are the ADV of sanitary pontics?

Answer 24

Easier cleaning

Robust shoulder joint- less chance of patient sectioning bridge

Narrower occlusal surface- avoids shear forces in lateral excursion

Question 25

What are the advantages of intermediate bridges?

Answer 25

Can be used during healing process

Can help us assess tooth contacts and aesthetics

Question 26

Why may patient with bruxism require one implant for each lost tooth?

Answer 26

To deal with the excess load (prevent bone loss and failure)

Question 27

What can be done so you can take an impression for a longer term temporary bridge following an extraction?

Answer 27

Put gauze in extraction socket
-> Can take 3-6 months for socket to heal and bone resorption to occur- definitive bridge can be placed then

Question 28

What are the issues with worn dentures in patients with tooth wear?

Answer 28

It can increase the force coming from opposing teeth as OVD is lost increasing FWS

Question 29

How can an old worn denture be used to re-establish OVD when treating tooth wear?

Answer 29

Drill cone shaped holes and fill with composite to help re-establish posterior support on existing denture as temporary measure

-> Then re-establish OVD definitively by replacing denture

Question 30

What must we inform tooth wear patients of before they undergo any treatment involving indirect restorations?

Answer 30

Failure rates are much higher

-> understand limitations, pick good cases and seek advice by referral if required