Titanium medical implants used in bone-anchored hearing aids and dental prostheses may not be as robust as commonly believed, according to a British study published on Wednesday.

Writing in the journal Interface of Royal Society, researchers at the University of Birmingham reported that microscopic particles of Titanium (Ti) could be found in tissue surrounding the medical implants, which can potentially be pro-inflammatory and affect the performance of the device.

Globally, more than 1,000 tonnes of Ti is implanted each year into patients in the form of biomedical devices such as metallic prostheses, fixation and anchoring devices for orthopaedic, craniofacial and dental rehabilitation.

Researchers obtained tissues from patients undergoing scheduled revision surgery associated with bone-anchored hearing aids at University Hospitals Birmingham, and discovered a scattered and heterogeneous distribution of Ti in inflamed tissues taken from around failing skin-penetrating Ti implants.

They concluded that wear processes and implant debris were unlikely to be major contributors to the problem. In the absence of obvious macroscopic wear or loading processes, the researchers proposed that the Ti in the tissue result from micro-motion and localized corrosion in surface crevices.

The development of peri-implant inflammation may result in the premature loss of function of the implanted device or the requirement for revision surgery, and could have an impact on the wellbeing of patients.

"Our results emphasize the need to understand both the physical and chemical mechanisms leading to the dispersal of Ti species in tissue around implants and their potential to exacerbate inflammation," said Dr. Owen Addison at University of Birmingham.

"Titanium is still the most appropriate material to put into bone and to be used in these devices," said him, "However, these interesting findings demonstrate that improvements in these material can be sought."