Lithium Disilicate and 3D Printed Ceramics

Lithium disilicate restorations can be fabricated by what?

1. Milling

2. Pressing

What are the 3 steps of pressed lithium disiclicate?

1. Melting

2. Cooling

3. Simultaneous nucleation

What causes the pre-sintered lithium dislicate blocks to be purple or blue?

Added stain

Pre-sintered metasilicate is soft, this makes the block easier to ____ while reducing the wear of the milling _________.

mil

cutter

The stains are added by the manufacturer to distinguish between what?

Pre-sintered and fully sintered restorations

When fired, metasilicate particles transforms into _______ _______ particles (strong) and the puple stains are what?

lithium disiclate

burned away

According to ISO classifcation of dental ceramics, Lithium disilicate falls into which category?

Class 3

Which of the following is not an indication for lithium disilicate?

Posterior short span bridge

The minimal occlusal reduction prep requirement for full coverage lithium disilicate crown is what?

1.5mm

What is the correct sequence of cementing a lithium disilicate resotation?

1. Acid etch

2. Rinsing the acid

3. Applying silane coupling agent

4. Using resin cement

What are the 3 materials for cementation?

1. 5% HF

2. Silane

3. Resin cement

The type and concentration of the acid used for etching lithium disilicate restorations?

5% hydrofluoric acid

True or false: the silane coupling agent has a unique ability to bond organic tooth structure with inorganic cements?

True

True or false: It is recommended to use dual cure resin cement with lithium discilicate veneers?

False

The discoloration of dual cure resin cement is due to what?

Tertiary amine

What is the most common brand name of lithium disilicate?

E.max CAD

3D printed ceramic crowns that are resin based have what % or highter of cermaic filler?

50%

3D printed ceramic crowns are FDA cleared for definitve full crowns?

True

FDA approval for 3D printed full crowns is soley based on what?

The materials composition being greater than 50% ceamic fillers and is not supported by clinical studies demonstrating the intraoral longevity of such restorations

What is the reported flexural strength value of 3D printed ceramic crowns?

136 Mpa

The flexural strength of 3D printed ceramics is less than half of what?

lithium disiclicate

True or flase: The aethetic parameters of 3D printed ceamic are supprior to lithium disilicate?

False

Optical properties of 3D printed ceramics:

• Transulency?

• Surface finish?

• Shade availability?

• Fluorescene/ Opalescene?

• 3D printing process can introduce what?

moderate to low

rough

limited

limited

internal defects that reduce translucency and produce a rough surface finish

True or flase: 3D printed ceramic restorations follow the same cementation protocol as coventional glass ceramics?

False

True or false: 3D printed ceramic restorations follow the same cementation protocol as indirect resin restorations?

True

3Dd printed ceramics/ indirect resin restorations bonding protocol? (3)

1. Airborne paritcal abrasion (no ethcing with HF acid)

2. Adhesive

3. Resin cement

Airborne particle abrasion:

• Bond strength signiicantly improves with what? using what?

• However increasing abrasion results in what?

Airborne paritcal abasion, using aluminum oxide

Material weakening

3D printed ceramics have lower _____ and inferior _______, limiting their use where?

Care is needed during airborne particle abrasion, as execessive pressure can weaken what?

strength and esthetics

posteior and anaterior regions

weaken the material

Class 1 Porcelain:

• Strength?

• Brand name?

Less than 100 mpa

Noritake EX-3 Vita mark

Class 2 Leucite glass ceramics:

• Strength?

• Brand name?

greater than 100 MPa

IPS Empress

Class 3 Lithium disilicate high strength glass ceramics:

• Strength?

• Brand name?

Greater than 300 MPa

e.max

Class 4 Cubic containing zirconia:

• Strength?

• Brand name?

Greater than 500 mpa

lava esthetic, katana UTML

Class 5 tetragonal:

• Strength?

• Brand name?

Greater than 800 Mpa

ZirCAD LT

Flexural strength mpa:

• Enamel?

• Dentin?

• Lithium Dislocate?

750-1420

160-200

360

Fracture toughness MPa.m1/2:

• Enamel?

• Dentin?

• Lithium Dislocate?

0.7-1.3

1.2

3.2

Translucency parameter:

• Enamel?

• Dentin?

• Lithium Dislocate?

15-19

12-16

14

Contrast Ratio:

• Enamel?

• Dentin?

• Lithium Dislocate?

0.54

0.60

0.78