Dental Implants

What is a dental implant?
An implant is an artificial replacements for the tooth root and it look like a cylinder or a screw. A typical implant consists of a titanium screw with a roughened surface. It is anchored into the jaw bone and becomes a stable base for one or more artificial teeth. Implants offer stability because they fuse to the bone and this integration helps the replacement teeth to feel more natural than conventional substitutes.

History:
The Mayan civilization has been shown to have used the earliest known examples of endosseous implants (implants embedded into bone). In the 1950s research was being conducted at Cambridge University in England to study blood flow in vivo. These workers devised a method of constructing a chamber of titanium which was then embedded into the soft tissue of the ears of rabbits. In 1952 the Swedish orthopaedic surgeon, P I Brånemark, interested in studying bone healing and regeneration, adopted the Cambridge designed ‘rabbit ear chamber’ for use in the rabbit femur(thigh bone). Following several months of study he attempted to retrieve these expensive chambers from the rabbits and found that he was unable to remove them. He observed that bone had grown into such close proximity with the titanium that it effectively adhered to the metal. Brånemark carried out many further studies into this phenomenon, using both animal and human subjects, which all confirmed this unique property of titanium. He termed the clinically observed adherence of bone with titanium as ‘osseointegration’.

In 1965 Brånemark, placed the first titanium dental implant into a human volunteer, a Swede named Gösta Larsson.There are several types of dental implants; the most widely accepted and successful is the osseointegrated implant which forms a structural and functional connection between the living bone and titanium implant.

Anatomy of a dental implant:
A dental implant designed to replace a single tooth is composed of three parts: the titanium implant that fuses with the jawbone; the abutment, which fits over the portion of the implant that protrudes from the gum line; and the crown, which is created by a prosthodontist or restorative dentist and fitted onto the abutment for a natural appearance.

Implant Placement Procedure:
The surface an implant is treated either by plasma spraying, etching or sandblasting to increase its surface area and thus its integration potential. A small-diameter hole (pilot hole) is drilled into the jawbone at edentulous sites(lacking teeth) to guide the titanium implant in place. Drilling into jawbone usually occurs in several separate steps. The pilot hole is expanded by using progressively wider drills (typically between three and seven successive drilling steps, depending on implant width and length). Care is taken not to damage the osteoblast or bone cells by overheating. A cooling saline spray keeps the temperature of the bone to below 47 degrees Celsius (approximately 117 degrees Fahrenheit). After the hole has been drilled the implant is placed. Once properly torqued into the bone, a protective cover screw is placed on the implant, then the gingiva or gum is sutured over the site and allowed to heal for aprox 3-6 months for osseointegration to occur between the titanium surface of the implant, and the jawbone. There may be some swelling, tenderness or both for a few days after the procedure so pain medication is prescribed to alleviate the discomfort. A diet of soft, cold foods is often recommended during the healing process. In the second stage the implant is uncovered in another surgical procedure, usually under local anesthetic and a healing abutment and temporary crown are placed onto the implant. This encourages the gum to grow in the right scalloped shape to approximate a natural tooth’s gums and allows assessment of the final aesthetics of the restored tooth. Once this has occurred a permanant crown is fabricated and placed on the implant.
An increasingly common strategy to preserve bone and reduce treatment times includes the placement of a dental implant into a recent extraction site. In addition, immediate loading ( a procedure where the abutment is placed during the initial surgical procedure along with the implant) is becoming more common as success rates for this procedure are now acceptable.