Anterior full coverage crowns

Question 1

What are the indications for anterior full coverage crowns?

Answer 1

Aesthetics 
Broken down anterior teeth
Toothwear 
Trauma 
Atypical shape and hypoplastic conditions 
Milled crowns and attachments for dentures 
Retainers for cantilever bridgework 
To alter occlusion

Question 2

What are the contraindications for anterior full coverage crowns?

Answer 2

Other conservative restorative options are available
Poor OH
Very broken down tooth with caries extending subgingivally
Periodontal condition

Question 3

What are the different types of anterior crowns?

Answer 3

Metal ceramic
All porcelain
Other types

Question 4

What are the different all porcelain anterior crowns?

Answer 4

Porcelain jacket crown
Dentine bonded crown
CAD/CAM

Question 5

What are metal ceramic crowns and what is the prep for them?

Answer 5

Metal core and ceramic veneer
Heavy labial prep 1.5mm
Lighter palatal 0.7mm

Question 6

What option can be added to metal-ceramic crowns for bruxists?

Answer 6

metal backings

Question 7

Why are metal ceramic less aesthetic?

Answer 7

Due to metal substructure

Question 8

What are examples of porcelain crowns?

Answer 8

Porcelain jacket crown
Dentine bonded crown
High strength porcelain
CAD/CAM

Question 9

Describe the porcelain jacket crown

porcelain covered ceramic

Answer 9

The oldest type of all-ceramic crown
Very brittle before cementation
Not very strong type of all-ceramic crown

Question 10

What are dentine bonded crowns?

Answer 10

Use thin layer of glass ceramics (Feldspathic, Leucite reinforced, Lithium disilicate) relying on bonding to underlying tooth structure for strength

Question 11

What is the prep for dentine bonded crowns? What are they ideal for?

Answer 11

Light chamfer margin conservative preparation 0.7mm

Required for minimally restored teeth requiring crowns for aesthetic reasons

Question 12

How is a pressed all porcelain crown produced?

Answer 12

A strong core or full contour crown is produced by pressing ceramic material at high temperature on a die
e.g. Empress I, II

Question 13

How are castable ceramics made?

Answer 13

Dicor system
Wax pattern made, invested in a special investment and casted in a glass-ceramic material
The casting placed in a ceramic oven and left for several hours
Crystalisation process taking place giving a stronger core
The core is veneered with Feldspathic porcelain to achieve good aesthetics

Question 14

What is a glass-infiltrated high strength ceramic core system?
E.g. In-Cera, Spinel, In-Ceram Zirconia

Answer 14

In-ceram
An alumina core is formed using slip casting
This core is porous and is then infiltrated with glass
A dense cord is finally produced

Question 15

What are the 2 high strength core ceramics?

Answer 15

Pure alumina

Pure zirconia

Question 16

Why use CAD/CAM

Answer 16

Chairside CAD/CAM available
Reduced human error
Standardise restoration shaping processes
Produce higher and more uniform quality material by using commercially formed blocks of material
Use of materials that otherwise would be difficult to use i.e. zirconia, titanium

Question 17

What are the advantages of all porcelain crowns?

Answer 17

More conservative labial prep, but more destructive palatally (1.2mm)
More aesthetic due to absence of metal substructure and no metal showing at the margin

Question 18

Hoe are all porcelain crowns bonded to the tooth?

Answer 18

Procera, Express can be bonded but some cannot (Inceram) as the high strength porcelain is not etchable

Question 19

What’s the indication for Dentine bonded crown?

Answer 19

Minimally restored tooth
Aesthetics paramount
Suitable occlusion

Question 20

What’s the indications for high-strength porcelain

Answer 20

More heavily restored tooth

Aesthetics more important

Question 21

What’s the indications for metal ceramic crown

Answer 21

More heavily restored tooth
Heavier occlusion (e.g. bruxism)
Aesthetics less essential