After a 10-year clinical trial of a jaw joint replacement developed by Peter Quinn of the University of Pennsylvania School of Dental Medicine, the Food and Drug Administration has given it a thumbs-up.
Because of almost ceaseless motion a human jaw moves about 700,000 times a year as a person chews, talks, swallows and yawns the jaw, or temporomandibular joint, can become a problem for as many as 20 million Americans, said Quinn, chairman of oral and maxillofacial surgery at Penn Dental Medicine. Teeth grinding and injuries also take their toll.
"Temporomandibular disease is almost a uniquely female disease. Almost 90 percent of the people in the trial were female, and most had TMD as a result of slippage of a disc in the joint," Quinn said. "TMD in male patients is mostly due to injury."
"What we set out to do was get approval for a stock prosthesis," said Quinn, whose stock device is the first in history to get FDA approval through a rigorous pre-market approval process.
In 1991, Quinn paired with an orthopedic company called Biomet to design the appliance and do the requisite materials testing. Biomet later acquired a maxillofacial surgical company, W. Lorenz Surgical Inc., and the prosthesis is marketed as the Lorenz TMJ replacement system. The clinical trials got under way in 1995 at Penn, where 75 percent of the surgeries were performed, and UT Southwestern Medical in Dallas, TX, which accounted for the rest. The trials involved 285 patients and 403 joints. Both joints were replaced in some patients.