Post on 11-Jan-2016
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