Experimental long-term study of titanium ions eluted from pure titanium miniplates.

A long-term study of titanium miniplates, which are in wide clinical use, was conducted to clarify their usefulness as a permanent fixing device. We examined by scanning electron microscopy the surfaces of removed plates and the accumulation of titanium in the organs of Japanese white rabbits. Two years after implantation the titanium plates were only slightly corroded. In addition, marked titanium accumulation was noted in the organs, especially in the lungs. However, the accumulation of titanium in the organs of animals with left distomolar mandibular fracture was highest at 3 months after implantation, and then gradually decreased over 2 years. Titanium miniplates have recently been used clinically in humans and no adverse reactions have yet been reported. The present findings suggest the use of titanium miniplates as permanent fixing devices.