Biofilm-induced electricity in titanium dental implants: path forward to new materials and electrotherapy

Objectives: Between 1-15% of the patients receiving implants experience dental implant failure that results in the destruction of soft tissue and bone around the implant. Our recently-published study documented the release of titanium into the surrounding plaques of patients, indicating that titanium is not as inert as once thought. We showed that the electrical conductivity of titanium implants was responsible for the corrosion process. Using a bioreactor that simulated an implant in a patient’s mouth, we were able to control the electrical current spontaneously generated by the biofilm by turning it on or off. When the current was turned on, the dental implant released titanium into solution. However, when the current was turned off, much less titanium was released. From these experiments, we initiated a new study with twofold objectives:

1. Develop and asses a new nonconductive ceramic with Ti inclusions exposed for osseointegration.
2. Determine the effect of and external AC and DC current on a biofilm associated with regular Ti implants (electrotherapy)

Methods: The Ti-containing ceramic was prepared from Sun Ya porcelain or Grolleg clay. Ti mesh -100 powder was admixed to the porcelain or clay. Some specimens were fired under vacuum, some were pre-baked at 800 oC in air followed by firing under vacuum in an electric tubular furnace. Firing was done until cone 10 stage. Electrotherapy experiments were conducted in a bioreactor which was a two-terminal symmetrical electrochemical cell was made of a glass tube capped with rubber stoppers. Two titanium dental implants were integrated into the cell. The cell was filled with medium under sterile conditions.

Results: As of October 2015, a specimen of nonconductive Ti-containing ceramic was obtained, characterization is underway. Conductive ceramic (unwanted) was much easier to obtain than the non-conductive. The electrotherapy experiments are in progress.
Conclusions: We are exploring novel approaches to addressing implant failure