CERAMIC in DENTISTRY

•History & evolution•Types of ceramic•Usage of ceramic

What is ceramic?

Greek – keramikosSanskrit – to burnBahasa melayu - tembikar

A glass material made by shaping and then firing a non-metallic mineral such as clay at a high temperature

It is hard, brittle, non-metallic, heat resistant & corrosion-resistant materials

What is ceramic?

Non-metallic material are aluminium oxide (alumina) & silicone dioxide (silica)It is indicated to be used when aesthetic is needed & when the size of the preparation exceeds the limit for the use of direct composite resins

Historical perspectivesArcheologists have discovered human-made ceramics that date back to at least 24,000 BCThese ceramics were found in Czechoslovakia & were in the form of animal & human figurines, slabs & ballsThese ceramics were made of animal fat & bone mixed with bone ash & fine clay like material

The first use of functional pottery vessels in 9,000 BC. These vessels were most likely used to hold & store grain & other foodsAncient glass manufacture is closely related to pottery making, which flourished in Upper Egypt about 8,000 BC.

Historical perspectives

While firing pottery, the presence of calcium oxide (CaO) containing sand combined with soda & the overheating of the pottery kiln (an oven for baking/drying clay, bricks etc) may have resulted in a colored glaze on the ceramic pot

Historical perspectives

Experts believe that it was not until 1,500 BC that glass produced independently of ceramics & fashioned into separate itemsSince these ancient times, the technology & applications of the ceramics (including glass) has steadily increased

Historical perspectives

Composition of ceramics

Feldspar – 65%Silica (quartz) – 25%Kaolin Coloring agentOpaquersFluorescing agent

Types of ceramics

1. Reinforced Ceramic Core System

The support for the aesthetic ceramic is provided by another ceramic material, which has the necessary high strength & toughness but may lack the desired aesthetics

i. Alumina-reinforced porcelain jacket crown (PJC)

ii. Glass-infiltrated high strength ceramic core systems:

• In-ceram Spinel• In-ceram Alumina• In-ceram Zirkoniaiii. Pure alumina cores:• Procers all ceram

1. Reinforced Ceramic Core System

2. Resin-bonded Ceramics

The support of the ceramic is provided by the tooth structure itselfBy bonding the aesthetic ceramic directly to the enamel & dentineIn this instance the ceramic provides the necessary aestheticThe strength is provided by the ability to bond to the tooth tissues.

Glass-ceramics:a.Leucite-reinforced Feldspar Glass

Ceramicsb.Lithium Disilicate & Apatite Glass

Ceramicsc.Fluoromica Glass Ceramics

2. Resin-bonded Ceramics

3. Metal Ceramics

The aesthetic ceramic is supported by a strong & tough metal

Application in Dentistry

Ceramic Inlay

Utilize to restore teeth with minor to moderate size lesion that will permit a narrow preparation isthmus in an area of mouth where the aesthetic demand is highFor premolar, should have 1 intact marginal ridgeCan also be used in MOD cavity of molars

Ceramic Onlay

Can be used for restoring moderately large lesions on premolar & molar with intact facial & lingual surfaceFor MOD restoration with wide isthmusFor endodontically treated posterior teeth with sound buccal & lingual tooth structure

It will accommodate a wide isthmus up to 1 missing cusp in molarCeramic MOD onlay should be used cautiously because without sufficient occlusal thickness, this restorations are susceptible to fracture

Ceramic Onlay

Ceramic Onlay

All Ceramic Crown

Used when full coverage & maximum aesthetic must be combinedUsually for incisors because they only exhibit low to moderate stress during functionAlso used in dental implants

Porcelain fused to Metal Crown (PFM)

Feldspatic porcelain is usedContains varying amounts of crystallized leucite that influences properties such as strength & thermal expansion

Ceramic Veneer

In an intact teeth they are marred (spoil) by severe staining/development defect restricted to the facial surface of the toothAlso to restore moderate incisor chipping & small proximal lesions

Orthodontic Brackets

The most recent use foe ceramic in dentistryThe development & demand for these items has been driven solely by aestheticPolycrystalline alumina is the material of choice in this application

Orthodontic Brackets

Clinical Concerns

Surface careSecondary decayFracture repair

Surface care

Surface glaze produce by final porcelain firing enables the restoration to reflect light in manner similar to natural tooth structureThe glaze is very smooth but the material below the glaze is coarse & porousSurface integrity must be maintain if the restoration is to appear natural & not provide anchorage for plaque attachment

Secondary Decay

Surface glass can be scratched or chipped with the scaler, roughened by polishing with abrasive that are too coarse or etched by acid ecthUse fine abrasives for polishingAvoid application of acid etch to ceramic restoration surfaceBond may break & cement may slowly dissolve, exposing tooth prep & the inside of the restoration

Secondary Decay

Because of indirect restoration are cemented/bonded in position, the cervical area is of additional concernThis provide protected anchorage for plaque & pathway for bacteria to reach the tooth surface to initiate secondary decay

Fracture Repair

Small chips & fracture can be repaired with an acrylic resin composite materialIsolate with rubber damRestoration surface is roughed with burThen etched with either hydroflouric acid acidulated phosphate fluoride solutionAny exposed metal is covered with composite

Any exposed enamel is etched with phosphoric acidSilane linking agent is applied to the restoration surfaceUnfilled resin bonding agent is applied & curedCR material is appliedBut the above is not strong & usually the restoration need to be replaced

Fracture Repair