Composition of Implants
Today’s Dental Implants
The majority of dental implants currently available are shaped like small screws, with either tapered or parallel sides. They can be placed at the same time as a tooth is removed by engaging with the bone of the socket wall and sometimes also with the bone beyond the tip of the socket.
Current evidence suggests that implants placed straight into an extraction socket have comparable success rates to those placed into healed bone. The success rate and radiographic results of immediate restorations (the temporary crowns placed at the same time) of dental implants placed in fresh extraction sockets have been shown to be comparable to those obtained with delayed loading (the crowns placed weeks or months later) in carefully selected cases.
A typical implant consists of a titanium screw (resembling a tooth root) with a roughened or smooth surface. The majority of dental implants made out of commercially pure titanium, which is available in 4 grades depending upon the amount of carbon and iron contained. More recently grade 5 titanium has increased in use.
The grade five titanium named, Titanium6AL-4V (signifying the Titanium alloy containing 6% Aluminum and 4% Vanadium alloy) is believed to offer similar osseointegration levels as commercially pure titanium. Ti-6Al-4V alloy offers better tensile strength and fracture resistance. Today most implants are still made out of commercially pure titanium (grades 1 to 4), but some implant systems (Endopore and NanoTite) are fabricated out of the Ti-6Al-4V alloy. Implant surfaces may be modified either by plasma spraying, anodizing, etching or sandblasting to increase the surface area and the integration potential of the implant.
Implants of the Future
Some current research in dental implantology is focusing on the use of ceramic materials such as zirconia (ZrO2) in the manufacture of dental implants. Zirconia is the dioxide of zirconium, a metal close to titanium in the periodic table and with similar biocompatability properties. Although generally the same shape as titanium implants zirconia, which has been used successfully for orthopedic surgery for a number of years, has the advantage of being more cosmetically aesthetic owing to its bright tooth-like color. However, long-term clinical data is necessary before one-piece ZrO2 implants can be recommended for daily practice.