Dental Ceramics - Seminar / orthodontic courses by Indian dental academy

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Transcript of Dental Ceramics - Seminar / orthodontic courses by Indian dental academy

INTRODUCTION

PAGE 41

CONTENTS

INTRODUCTION

1

STRUCTURE

4

HISTORY

4

TERMINOLOGIES

14

CLASSIFICATION

24

COMPOSITION

26

PROPERTIES

36

STRENGTHENING OF DENTAL PORCELAIN

38

CONDENSATION OF DENTAL PORCELAIN

45

FIRING PROCEDURE

47

STAGES OF MATURITY

52

ALL CERAMICS

53

CLASSIFICATION

53

CONVENTIONAL POWDER SLURRY CERAMIC

HICERAM ALUMINA REINFORCED PORCELAIN

54

OPTEC HSP LEUCITE REINFORCED PORCELAIN

56

DUCERAM LFC - HYDROTHERMAL LOW FUSING CERAMIC60

PRESSABLE CERAMIC

IPS EMPRESS

61

OPTEC PRESSABLE CERAMIC

INFILTRATED CERAMIC

INCERAM

66

CASTABLE CERAMIC

DICOR

73

CERA PEARL

79

MECHINABLE CERAMIC

CEREC VITBLOCS MARK I AND II

83

CELAY BLOCKS

132

REFERENCES

136

INTRODUCTION

Man has been obsessed with duplicating, restoring and replacing various lost body parts like the limbs, ear, nose and eyes with artificial prosthesis and teeth being no exception. Restoration of teeth is not recent but ancient, dating back to 1st century Roman B.C. Many materials have been used to restore and replace a lost teeth or a part of it, of these ivory was popular but not without its disadvantages.The quest for an artificial prosthesis similar to the nature tooth, both in function and esthetics, in the oral environment still remains as a foremost concern to the dentist, which has led to the use of CERAMICS in dentistry.

CERAMICS

Ceramics are defined as man-made solid objects formed by nonmetallic and inorganic raw materials that are baked at high temperatures. Stoneware and pottery are still made from impure clays, sand and feldspar minerals, and are baked in kiln,s First pulvering the raw materials into a fine powder and then adding water to obtain a working consistency for shaping and molding makes these objects. The unbaked objects dried and placed in a kiln and heating to sufficiently high temperatures to make the individual particles coalesce into a solid mass.

Ceramics are nonmetallic, inorganic materials that contain metal oxides whose structure is crystalline, displaying a regular periodic arrangement of the component atoms and may exhibit ionic or covalent bonding. Also a low-fusing glass matrix filled with high-fusing filler. It is heated above the fusing temperature of the low-fusing glass but well below the temperature needed to fuse the high-fusing filler. The filler, as in composite resins, improves strength and esthetics.

Glasses are described as supercooled liquids, not structureless or truly amorphous like a gas. In liquids, structural units or arrangements of atoms exist as they do in crystalline solids, but these units are not arranged in a regular manner. Glasses and liquids differ in one respect in a glass, each atom has permanent neighbours at a farily definite distance while in a liquid the neighbours about any atom are continually changing. Glass is an inorganic product of fusion, which has cooled to a rigid condition without crystallization. Common glass is made of silica sand, sodium oxide and potassium oxide, and by adding aluminium oxide a plate glass is made. If silica is heated to 1000oC and then gradually increased in temperature to 1500oC over the course of hours it changes into cristobalite. Tridymatie is an impurity of cristobalite and is formed when the quartz is heated between 870-1470oC. Enamels are closely connected to the glass industry as they may be compared to fusible glass made opaque by adding opacifiers.Porcelain is a type of ceramic. All porcelains are ceramics but all ceramic are not porcelains. The traditional porcelain is composed of three naturally occurring minerals: pure white clay (kaolin), silica (quartz), and feldspar. After baking it is known as whiteware because of its color from the clay. The basic components of dental porcelain are silica and feldspar. Additional components are aluminium oxide as well as pigments and opacifying agents, depending on the application.Ceramics, industrial porcelains and dental porcelains are fabricated from the same compounds, it is merely the concentrations of the various components that differentiate them.

STRUCTURE (0

0

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(( 0 ( Si ( 0 ( Si ( 0

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0

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(HISTORY OF CERAMIC

Aesthetics and durability of material in the oral environment has always been a foremost concern to the dentist and is still a foremost concern to the dentist.The desire for a durable and aesthetic material is ancient although dental technology existed in Etrutia as early as 700 B.C. and during the Roman 1st Century BC. Little progress took place in dental art from the beginning of the Christian era to about 1500 AD. This was described as the dark ages of physical activities, a probably there was much activity, creative though and invention, but records were either not kept or later destroyed.

Artificial teeth were made from

1. Animal products such as ivory teeth or bone

These were unsatisfactory because they tend to deteriorate and disintegrate in the mouth and absorb stains and odour.

AMBROISE PARE (1562) is credited for having prepared artificial teeth from bone and ivory.

JACQUES GUILLENMEAU was a pupil of PARE, who prepared a substance by fusing certain waxes, gums, ground mastic, powdered pearl and white coral. This may have been the forerunner, in principle of esthetic fused porcelains, which appeared many years later.

2. Teeth taken from the mouth of dead persons

The disadvantage were,

Expensive

Scared people

Developed a natural repugnance to put a corpses teeth into their mouth.

Repeated failures

Risk of transmitting diseases like syphilis

3. Bamboo

The disadvantages of bamboo are esthetically poor and functionally not durable in the oral environment.

4. Mineral tooth or Porcelain tooth CERAMICS originally referred to the art of fabricating of pottery.

The term ceramic is derived from the Greek term KERAMOS, which means A POTTER OR POTTERY.

It is believed that this word is realized to a Sanksrit term meaning BURNED EARTH, since the basic components were clays from the earth, which were heated to form pottery (FRIEDMANN 1991).

Ceramic is a non-metallic, inorganic material. The term CERAMIC applies to a wide variety of materials, including metal oxides, borides, carbides, nitrides and complex mixture of these materials.

Ceramic objects have been constructed for thousands of years. The earliest techniques used were crude. It consisted of shaping the item in clay/soil and then baking it to fuse the particles together, which resulted in coarse and porous products such as goblets and other forms of potter.

21,000 BC; earliest man-made ceramic artifacts were dated.

5000 BC: clay pots were discovered.

Later development led to detailed stoneware items

100 BC: colored, glazed vessel made (Han Dynasty)

600 BC: translucent porcelain made (Tang Dynasty)

Egyptian faieces are the first to enamel a substructure with a ceramic venner. Their typical blue green hues resulted form metal oxides created during the firing process.

More recently the Chinese ceramist developed porcelain. Vitrification, translucency, hardness and impermeability characterized it.

In the 17th century, the Europeans attempted to develop porcelain of similar quality that of the Chines. By 1720s the Europeans mastered the art of manufacturing fine translucent porcelain. This lead to the promulgation of information regarding the fundamental components of porcelain: KAOLIN and FELDSPAR.

In 1723, enameling of metal denture bases was described by PIERRE FAUCHARD, which initiated research in porcelain that imitates color of the teethand gingival tissue.

By 1774, a Parisian apothecary ALEXIS DUCHATEAU with the assistance of a Parisian dentist NICHOLAS DUBOIS de CHEMENT made the first successful porcelain dentures at the GUERCHAND PORCELAIN FACTORY, replacing the stained and malodours ivory processes.

NICHOLAS DUBOIS worked diligently at perfecting the invention (a very difficult achievement because the one-piece denture had to resist distortion during firing).

In course of his experiments, DUBOIS continuously improved his porcelain formulation and was awarded both French and English patent.

He termed them UNCORRUPTIBLE TEETH that gained wide currency and for many years was synonymous with porcelain teeth.

In 1817, a French immigrant dentist, ANTOINE PLANTON introduced individual porcelain teeth in America.

In 1837, CLAUDIUS ASH produced fine porcelain teeth and later went on to introduce TUBE TEETH which could be inserted over a post on a denture. It became widely accepted for use in bridges as well as in full dentures.

In 1851, JOHN ALLEN of Cincinnati patented CONTINUOUS GUM TEETH prosthesis consisting of two to three porcelain teeth fused to a small block of porcelain colored like gingiva.

The search for suitable tooth colored filling material continued and was led by the prominent artist-dentist ADELBERT.J.VOLCK who brought about somewhat unsatisfactory products as early as 1857.

The modern synthetic porcelain or silicate cements-porcelain inlays fashioned to fit prepared cavities precisely were marketed first in 1880.

In 1882, glass inlays (not porcelain) was introduced by HERLRST.

In 1885 LOGAN fused porcelain to platinum