Dental Porcelain/Ceramics

What is porcelain in plain language?

It is a powdered glass that when fired at extreme temperatures, forms together to make a solid, glass-like structure

Fill in blanks

Porcelain has been used as a dental restoration material since ___ in the form of ____

• porcelain crowns

• inlays

Plastics became available in ____ and the porcelain restorations ____

• in the mid-forties

• lost favor

New metal alloys and new porcelains in _____ allowed development of ___ crowns

• in the sixties

• PFM

What techniques used to process porcelain?

• powder/liquid

• pressable materials

• CaD, CaM/Machined ceramic

Give an example of pressable material

Lithium Disilicate

Give an example of machined ceramic/CAD CAM

-Zirconia

-Aluminum Oxide

Characteristics of dental Porcelain/ powder-liquid

1. Similar light _ and _ qualities to natural teeth

-refraction

-reflection

dental porcelain is biocompatible? T or F

T

3. _ to oral fluids

Insoluble/ does not dissolve

4. Ease of ___

Customization

Porcelain may shrink during its firing cycle by __?

12-30%

• may require building the unit oversized

Shrinkage of the porcelain depends upon

the number and size of spaces between the porcelain particles before the porcelain is fired

Spaces can be minimized by

• removing excess moisture during build up

• condensation of the porcelain

Fill in blanks

Porcelain must be ___ during its green stage to __

damp

to allow for manipulation and application of the material/ carving

Main ingredients for dental porcelain

1. feldspar/feldspathic porcelain - 50-66%

2. quartz/silica- 7-14%

3. alumina - 7-20%

4. pigments/ opacifiers 1-7%

Match correct answer

1. Feldspar a. helps the crown hold its form during firing

2. alumina b. gives porcelain its translucent, glass- like appearance

3. quartz c. the strongest component of dental porcelain, provides increased overall strength .

4. pigments d. provide the shade/color for the finished restoration

1. b

2. c

3. a

4. d

Quartz has extremely high fusion temperature. True or False

true

The main 2 purposes for opaque porcelain?

1. mask our the underlying metal substructure

2. establish a porcelain to metal bond

Gingival/ Dentin/Body Porcelain

1. provide the overall shade of your restoration

2. can be modified to accommodate customized shades

Incisal/Enamel porcelain

• make up the incisal part to mimic the enamel of natural teeth

• used on the proximal contact areas

translucent porcelain

• not transparent

• do not allow the transmission of all light

• applied over the entire build up surface

• gives depth and natural enamel like translucency without altering the body shade

body modifier porcelain

• color concentrated and are designed to aid in internal color modification.

• can be diluted

• can de used full strength

• can be used in areas where space is limited to achieve the appropriate shade

stain and glaze porcelain

• stains are used to fine tune the shade

• glazes are colorless. low fusing. They fill small surface porosities and recreate the external sheen/ glossy appearance of the natural tooth

Corrective porcelains

• fire at lover temperatures

• used to make minor corrections at the very end