Dental implants can be used to support a number of dental prostheses, including crowns, implant-supported bridges or dentures. They can also be used as anchorage for orthodontic tooth movement. The use of dental implants permits undirectional tooth movement without reciprocal action.
A typical implant consists of a titanium screw (resembling a tooth root) with a roughened or smooth surface. The majority of dental implants are 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. Grade 5 titanium, Titanium 6AL-4V, (signifying the Titanium alloy containing 6% Aluminium 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 are fabricated out of the Ti-6Al-4V alloy. Implant surfaces may be modified by plasma spraying, anodizing, etching, or sandblasting to increase the surface area and osseointegration potential of the implant.
Results published in FASEB (the journal of the Federation of American Societies for Experimental Biology) by researchers at Columbia University, including Jeremy Mao of the Columbia College of Dental Medicine, demonstrate a novel way of using porous structures as a drug delivery vehicle that can help boost the integration of host tissue with surgically implanted titanium.
Instead of being acted upon by the body as an impenetrable foreign object, the synthetic bone replacement currently being tested in rabbits features a porous material that allows for the delivery of "microencapsulated bioactive cues" that speed up the growth of host tissue at the site and allow for the growth of new bone.
A critical finding is that the drug dose needed for host tissue integration by this controlled-release approach is about 1/10 of that by the traditional technique of simple adsorption of the growth factor.
The approach could bring to orthopedics and dentistry a treatment that has wrought much interest and success in the field of cardiology with the development of drug-eluting stents, which take what is ordinarily an inert tube, and infuse it with drugs to make the placement of what is essentially a man-made, foreign object more compatible with the patient's body, and at the same time, actively promoting healing of injured tissue.
