The science of dental materials

involves the study of the composition

and properties of materials and the way

in which they interact with the oral

environment in which they are placed.

Dental materials may be classified:

- impression materials,

- wax,

- metals,

- polymers,

- ceramics

Metals

Metals are used for making restorations of the

lost tooth structure, prosthetic devices,

orthodontic appliances, and many other

applications where strength and elasticity are

required.

A mixture of two or more metallic elements is

called alloy (Gold alloy &Cobalt chromium alloy)

Metallic restoration

COBALT CHROMIUM ALLOYS

• Cobalt based alloys are used in one of three forms

• Cast; as prepared

• Wrought (fine structure with low

carbon contents ; pure forms)

• Forged

Cobalt based alloys are better than stainless steel devices because of low corrosion resistance

• Wrought alloy: • possess a uniform microstructure with fine

grains.• Wrought Co-Cr –Mo alloy can be further

strengthened by cold work.

• Forged Alloy: • produced from a hot forging process. • Forging of Co-Cr –Mo alloy requires • sophisticated press and complicated tooling. • Factors make it more expensive to fabricate a

device

TITANIUM BASED ALLOYS

• The advantage of using titanium based alloys as implant materials are

• low density

• good mechano-chemical properties

• The major disadvantages

• relatively high cost

• reactivity.

• Polymers

• Polymers are synthetic resins.

• Types of dental polymers:

• Polymeric impression materials.

• Denture base materials.

• Tooth colored restorative materials.

• The structures of polymers determine their utilization in • various medical domains like in surgery, dermatology, • ophthalmology, pharmacy,depending on chemical and

• physical properties.

• The stability and lifetime of polymers in long-term • implantation depend not only on chemical structure of

the • material employed but also on the conditions under • which they are utilized.

• Biomedical polymers can be classified into either • elastomers or plastics.

Ceramics

Ceramics include a wide variety of

substances such as glass, cement,

refractory (high temp), and many

other materials.

Types of dental ceramics:

Dental porcelain.

Dental cements.

Gypsum products.

Casting investment

Ceramic restoration

Ceramo-metal system

Bridge