3. metal and alloys

Metals and Alloys

A metallic material composed of one or more chemical elements that is,

Opaque

Ductile

Relatively malleable

A good conductor of electricity

A good thermal conductor

Usually lustrous when light is reflected from its polished surface.

metal vs non metal

MALLEABILITY

one of the most important characteristic of the material in dentistry.

The ability of a material to undergo plastic deformation before fracturing,
allowing it to be hammered or shaped without breaking.

properties of metals in dentistry

Alloys

A crystalline solid with metallic properties that is composed of
two or more chemical elements

at least one of which is a metal and all of which are mutually soluble in
the molten state.

Microstructure

Metals combine to help distributing stress throughout the material, which
helps resist fracture and deformation

Classification of metals

1. base

2. noble

base metal

Easily corroded

Low density

Low mechanical properties

noble metal

Not easily corroded

Higher density

Better mechanical properties

gold + platinum group metals

density of metal and alloys

Identalloy

we can classify how much of a noble metal we have in proportion to base metals

Classification of Alloys

there are 3 types of Alloys

1. high noble (HN) alloys

2. noble alloys (N)

3. predominately base alloys (PB)

HN alloys

N alloys

PB alloys

tarnish

superficial discoloration or dulling of a metal surface that is often caused by a rxn with oxygen or sulfur

some metals are protected by a naturally forming adherent oxide coating

Different colors of metallic oxides

Iron or Zinc oxide: Brown

Copper oxide: Green

Titanium oxide: Yellow brown

Manganese oxide: Lavender

Cobalt oxide: Blue

Opacifiers: Zirconium, Titanium, Cerium, Tin oxides

PB alloys

chromium

increases corrosion resistance by forming adherent oxide film on surface

Ni-Cr

used for casting FDPs infrastructures, cast posts

stainless steel

Fe and Cr

used for instruments, ortho wires, brackets + pedo crowns

co-cr

used for RPD infrastructures and carbide burs

NI-TI

highly corrosion resistant

a variety of alloys and pure are used for implants, ortho wires, endo instruments

lost wax technique

process in which a wax pattern, prepared in the shape of missing tooth structure is embedded in a casting investment and burned out to produce mold cavity into which molten metal is cast

CAD/CAM

computer-aided design and computer-aided manufacturing

refers to computer software that is used to both design and manufacturing products

CAM software uses the models and assemblies created in CAD software to generate tool paths that drive the machines that turn the designs into physical parts