Porcelain is a white ceramic containing glass with a glazed surface or white , translucent ceramic that is fired to a glazed state. It is used for construction of crown and bridge. If its used alone for making crowns, they are called porcelain jacket crowns (PJC).

PORCELAIN

PORCELAIN CROWN BEFORE AND AFTER

INTRODUCTION TO CERAMICS

  • Derived from a Greek word :keramos
  • Keramos literally means burnt stuff or a material produced by burning or firing.
  • Ceramics are solid inorganic compounds with various combinations of ionic or covalent bonding
  • Ceramics are formed from non-metallic materials fired at a high temperature
  • They have more complex crystal structure than metals
  • Historically ceramic was used initially for making denture teeth
  • Dental ceramics are Hard, Brittle , Incombustible ,Corrosion resistant AND Stable  meaning they do not react with liquids, gases ,alkalis and acids
  • Poor conductors of heat and electricity
  • They are Light(in general lighter than metals)
  • The first fabricated ceramic consisted mainly of kaolin ; such ceramic was weak , porous and opaque
  • Kaolin was then blended with silica and feldspar to give extra strength and translucency
  • Such materials were given the name porcelain
  • Porcelain refers to ceramics composed mainly of kaolin , silica (quartz) and feldspar fired at high temperature.
  • In dentistry porcelain is used for making Artificial teeth, Crown, Bridge and veneers.

 

PORCELAIN

ETYMOLOGY

  • It derives its present name from the old Italian porcellana (cowrie shell)

BRIEF HISTORY

  • Porcelain can informally be referred to as “china” or “fine china” in some English-speaking countries, as China was the birthplace of porcelain making
  • It was used to make artistic objects and decoration pieces

COMPOSITION

  • It contains crystalline ingredients held together in a clear liquid like glass structure.
  • Availability :bottle
  • Presentation : Fine powder
  • Dental porcelain is manufactured from three primary ingredients:

1.Kaolin or china clay(Al2O3.2SiO)2 2H2O

2.Silica( SiO2) in the form of quartz

3.feldspar(K2o.Al2O3.6SiO2)(potassium alumino-silicate)

CLASSIFICATION

  • Traditional porcelain are classified according to their fusion temperature as:
  • High fusing: 1300-1400
  • Used to make denture teeth
  • Medium fusing:1093-1260
  • Used to fabricate jacket crowns (PJC)
  • Low fusing:850-1100
  • Used to make the material fused to metal crowns (PFM)

PROPERTIES

  • Most important properties are:
  • Flexural strength
  • Brittleness
  • Co-efficient of thermal expansion
  • Hardness
  • Color
  • Miscellaneous properties

BRITTLENESS

  • It is very rigid ,hard and brittle material.
  • Traditional it has
  • Low value of tensile strength:20-40MPa
  • High value of compressive strength:350-550MPa

COLOR

  • It was developed for dental use because of its super aesthetics
  • Available in range of shades and various levels of translucency
  • Aesthetics qualities of porcelain do not deteriorate with time
  • Displays excellent colour stability
  • Matching ceramic colour to existing teeth is very critical
  • Matching is accomplished using shade guide

MISCELLANEOUS PROPERTIES

  • It is completely insoluble in oral fluids and is very resistant to chemical attack
  • It is unaffected by the wide variation of pH in the mouth
  • It is extremely well tolerated by oral tissues.
  • It is Inert and has no interaction with surrounding tissues, completely biocompatible

MAINTENANCE

  • Its surface accumulates more plaque than a glazed surface
  • Crown margins tend to accumulate plaque,hence harder to clean
PORCELAIN

PORCELAIN VENEERS

PORCELAIN VENEERS

They are thin pieces of the material used to recreate the natural look of teeth.

 

PORCELAIN

 

NEW ADVANCEMENTS

  • Zirconium crowns are being used, they are :-
  • (1) Extraordinarily tough
  • (2)Very strong, can withstand wear and tear.
  • 3) from an aesthetic point it is clear and very similar to a natural tooth and reflects light the same way
  • (4) Less tooth removal
  • (5) Zirconium crowns won’t corrode
  • (6) No Metal fuse

PORCELAIN

 

PORCELAIN