Dental Implants (Tooth Implants)
A) What is an implant?
Tooth implants are dental devices that have been designed to substitute for individual missing teeth.
"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 jawbone).
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 our picture to the right.)
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) Tooth implants have three basic parts.
#1) The implant "fixture."
The fixture is that part of the implant that is 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 root.
(In our animation below, Image #1 shows an x-ray of an implant fixture embedded in the patient's jawbone.)
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, cylindrical or screw-shaped design.
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).
Special fixture coatings.
The surface of a fixture may be coated with a special bone-regeneration material such as hydroxyapatite. Some manufacturers feel that this helps the osseointegration (fusion) process take place more rapidly. (The need for this is also disputed.)
#2) The implant abutment.
The abutment portion of a tooth implant is that part that lies at and above the gum line. It's the part that supports and secures the dental work (crown, bridge, denture) that's placed on it.
The abutment is typically not added to (screwed on) the implant fixture until after the osseointegration process (implant-to-bone fusion) has taken place.
(In our animation above, Image #2 shows an x-ray of an implant fixture with its abutment in place.)
#3) The dental prosthesis.
The dental prosthesis refers to the dental work that the implant supports.
Depending upon its design, it may be cemented or screwed (i.e. crowns, bridgework), or else clipped or snapped (i.e. dentures), into place.
(In our animation above, Image #3 shows an x-ray of an implant that supports a dental crown.)