Dental implant Parts

What are they? / The component parts of an implant (fixture, abutment, prosthesis). / Basic cases (conditions, situations) where implants should not be placed.

A) What is an implant?

Dental implants are mechanical devices that have been designed to substitute for individual missing teeth. They function as an artificial tooth root, on top of which some type of dental prosthesis (a dental crown, bridge or denture) can then be placed.

A dental implant used to replace a molar.

"Endosseous root-form" tooth implants.

The most common kind of implant placed by dentists is the "endosseous root-form" type.

• The term "endosseous" refers to the fact that the implant is embedded within bone.
• The term "root form" refers to the fact that the shape of the implant is somewhat similar to the shape of a natural tooth's root. (This isn't precisely accurate in the sense that some teeth have multiple roots. - See animation.)

"Osseointegrated" implants.

The term "osseointegrated" (or "osteointegrated") refers to the fact that there is a direct connection (fusion) between the surface of the implant and living bone tissue. Virtually all endosseous root-form implants are the osseointegrated type.

B) The component parts of an implant.

The fixture and abutment parts of a dental implant.

#1) The implant "fixture."

The fixture is that part of the implant that's embedded in and becomes fused with the jawbone.

It's the portion that lies below the gum line and, for all practical purposes, can be considered to be an artificial tooth root.

a) Fixture construction.

Osseointegrated implant fixtures are made out of the metal titanium. It may either be "commercially pure" (over 99.5% pure) or an alloy (titanium combined with aluminum and vanadium, so to improve strength and fracture resistance).

Fixtures can have a hollow or solid, and then cylindrical or screw-shaped design.

Component parts of an implant: a) Implant fixture. b) The abutment. c) The crown.

b) Special surface treatments.

The metal surface of the fixture portion of an implant may be smooth. As an alternative, some manufacturers grit-blast, machine or etch this surface so to roughen it up at a microscopic level.

Doing so increases the total external surface area of the fixture, thus increasing the amount of bone-to-implant fusion that takes place. (The need or benefit of this extra treatment is disputed.)

c) Special fixture coatings.

The surface of a fixture is sometimes coated with a special bone-regeneration material such as hydroxyapatite. Some manufacturers feel that this helps the osseointegration (fusion) process to take place more rapidly. (The need for this is also disputed.)