The coating includes a crystalline inner layer and a mostly amorphous outer layer that connects to the surrounding bone. The outer layer dissolves over time, releasing phosphate and calcium, with both fostering bone growth.
Co-author of the paper, Dr. Afsaneh Rabiei, claims, "The bone grows into the coating as the amorphous layer dissolves, resulting in improved bonding, or osseointegration.” This bonding makes the implant more functional since the bonding helps to ensure the bone and the implant can better share the load.
Dr. Rabiei adds, “We call it a smart coating because we can tailor the rate at which the amorphous layer dissolves to match the bone growth rate of each patient.” This is important since different people have highly different rates of bone growth. For example, older individual’s bones tend to grow much more slowly than younger adults.
The researchers also used silver nanoparticles throughout the coating to prevent infections. Currently, implant patients must undergo an intense regimen of antibiotics to ward off infection immediately after surgery. However, by infusing silver into the coating, the silver particles act as antimicrobial agents as the amorphous layer dissolves. This not only reduces the amount of antibiotics a patient will need following surgery, but will also prevent further infection during the life of the implant.
In addition, the silver is released more quickly immediately following surgery when the faster dissolution of the amorphous layer causes risk of infection to be at its highest. During the healing time, the silver release will begin to slow down, a reason why the treatment is called “smart coating”.