PRD 132: Crown Prep on Anterior Tooth (lithium Disilicate

Ceramic

Zirconium oxide is a

Silicate (glass)

Lithium disilicate and zirconia reinforced silicate ceramics

Glass ceramic

Lithium disilicate is a type of

Layered/monolithic; pressed/milled

Lithium disiliciate can be ___ or __

Aesthetics

We mostly use lithium disilicate for

Aluminum oxide

Minimized chemical solubility

Potassium oxide

Lowers the viscosisty

Phosphorus pentoxide

nucleating agent and helps bulk crystallizing process

Zirconium oxide

Nucleating agent and helps promoting surface crystallization

Zinc oxide

Improves chemical stability, optical translucency

Magnesium oxide

Increases the viscosity of glass matrix

Pigments/color fluorescence

For aesthetics

Veneers

We use lithium disilicate for ___ (thin 0.4 mm and conventional)

Partial crowns

We use lithium disilicate for ___ (inlays, onlays, overlays)

Single crowns

We use lithium disilicate for ___ IN ANTERIOR AND POSTERIOR AREAS

Three unit bridges

We use lithium disilicate for __ IN THE ANTERIOR AND PREMOLAR AREAS

DEEP SUBGINGIVAL PREPARATION

A major contraindication for lithium disilicate is (prep)

Four unit bridges

A major contraindication for lithium disilicate is (too much to support)

Missing teeth

A major contraindication for lithium disilicate is PATIENTS WITH SEVERELY REDUCED RESIDUAL DENTITION

Bruxium

A major contraindication for lithium disilicate is (teeth grinding)

Conventional/digital

An advantage of lithium disilicate is that you can take __ impressions

Aesthetics

An advantage of lithium disilicate is that it has high ___ to natural tooth

Same day

An advantage of lithium disilicate is that you can do Chair-side CAD/CAM production process

indications

An advantage of lithium disilicate is that it has Wide range of __ from thin veneers to three-unit

bridges

Biocompatibility

An advantage of lithium disilicate is that it has __, less plaque accumulation

Intraorally

An advantage of lithium disilicate is that it can be __ repaired in case of chipping

bonding

A disadvantage of lithium disilicate is that it has to be cemented by __ (technique sensitive) advantage of lithium disilicate is that

Thermal processing

A disadvantage of lithium disilicate is that __ can influence the strength of LD

restorations.

Brittle

A disadvantage of lithium disilicate is that it has Intrinsic __ behavior.

literature

A disadvantage of lithium disilicate is that there is a distinct lack of __ discussing long-term survival

and outcomes for the material.

Monolithic Zirconia or FVC

Lithium disilicate is Less bright than

__ (metal alloy)

Ingots, blocks

What are two types of lithium disilicate

Pressed

___ LD is Produced according to a unique bulk casting

production process to create the ingots

E max press

Ivoclar vivident ingots

E max CAD

Ivoclar vivadent blocks

Pressed ingots

The ___ LD is more fracture resistant

70%

The pressed ingot LD Microstructure consists of approximately __ needle production process to create the ingots like lithium disilicate crystals embedded in a glass matrix, approx 3-6 microns in length

3-6 microns

The pressed ingot LD Microstructure consists of approximately 70% needle production process to create the ingots like lithium disilicate crystals embedded in a glass matrix, approx __ in length

lost-wax hot-pressing

Pressed ingots Utilizes in __ technique in which lithium metasilicate in ingots are converted to lithium disilicate.

70%

Pressed ingots is pressed into the mold at approximately 850 degree Celsius for 20-25 minutes to form __ volume of crystalline lithium disilicate

lab

Heat-pressed technique must be done in the ___ and, requires higher manufacturing time and technical skills

Milled LD

Require intermediate (partial) crystallization to ensure blocks can be milled efficiently in an intermediate blue phase

lithium metasilicate

In milled LD, the intermediate process leads to formation of __ crystals.

40%

The lithium metasilicate crystals are __ platelet shaped lithium metasilicate crystals embedded in glass, range from 0.2-1 micron. Flexural strength is ~ 130Mpa

70%

Post crystallization (after firing) milled LD microstructure consists of __ fine grained lithium disilicate crystals embedded in a glass matrix

CAD-CAM technology

In milled technique, The __ charge-coupled camera device is used for making

3D impression of the tooth and crown is designed.

milled

Based on this digital information, block is __ to form a restoration

40%

Non-fired blue blocks consist of about __ vol % crystals embedded in a glass matrix (mostly lithium metasilicate, small amount of lithium orthophosphate, and lithium disilicate)

technically efficient

Machine milled more __ and can be done in a single appointment.

Milled/pressed

Like LD, Bilithic Zirconia (Porcelain fused to Zirconia) could

Be

milled; pressed

For Bilithic Zirconia, the zirconia substrate will be __

first, then the Porcelain or LD part will be __ over it.

2

Second the putty into __ halves not 1/3s

1mm

Cervical reduction

1-1.2mm

Fossa reduction

1-1.5mm

Facial reduction

1.5-2mm

Incisal reduction

Football bur

Use on lingual surface

Two planes

The facial reduction you must follow the

Path of insertion

the direction in which the RPD is inserted & removed from the abutment teeth (cervical follows)

3-5 degree

There should be a ___ taper

Dental ferrule

A band (of tooth structure) that encircles the external dimension of tooth structure

fracture

Ferrule Provides __ resistance

(more about that with endo)

retention

Ferrule Provides adequate __ and

resistance for the indirect

restoration

external

Ferrule Distributes __ forces evenly

2-3mm

Ideally, Maintain a height of_____ on the lingual wall (1.5-2 mm is ok)

Sharp edges

A common error are

Undercut

A common error is

Overtaper

A common error is

Under reduced

A common error is

Over and under reduced

Black

J lip

Blue

Margins more than 0.5mm above gum

Red

End cutting bur

Fix j lip with