US researchers are developing a smart dental implant that resists bacterial growth and generates its own electricity through chewing and brushing to power a tissue-rejuvenating light. The innovation could extend the usable life of an implant.
In a paper published in Applied Materials & Interfaces, a team from the University of Pennsylvania School of Dental Medicine lay out their platform.
The novel implant would implement two key technologies. One is a nanoparticle-infused material that resists bacterial colonisation. And the second is an embedded light source to conduct phototherapy, powered by the natural motions of the mouth, such as chewing or toothbrushing.
“Phototherapy can address a diverse set of health issues,” Dr Geelsu Hwang said.
“But once a biomaterial is implanted, it’s not practical to replace or recharge a battery. We are using a piezoelectric material, which can generate electrical power from natural oral motions to supply a light that can conduct phototherapy, and we find that it can successfully protect gingival tissue from bacterial challenge.”
The material the researchers explored was barium titanate (BTO), which has piezoelectric properties that are leveraged in applications such as capacitators and transistors, but has not yet been explored as a foundation for anti-infectious implantable biomaterials.
To test its potential as the foundation for a dental implant, the team first used discs embedded with nanoparticles of BTO and exposed them to Streptococcus mutans, a primary component of the bacterial biofilm responsible for tooth decay commonly known as dental plaque.
They found that the discs resisted biofilm formation in a dose-dependent manner. Discs with higher concentrations of BTO were better at preventing biofilms from binding.
While earlier studies had suggested that BTO might kill bacteria outright using reactive oxygen species generated by light-catalysed or electric polarisation reactions, the researchers did not find this to be the case due to the short-lived efficacy and off-target effects of these approaches. Instead, the material generates enhanced negative surface charge that repels the negatively charged cell walls of bacteria. It’s likely that this repulsion effect would be long-lasting.
“We wanted an implant material that could resist bacterial growth for a long time because bacterial challenges are not a one-time threat,” Dr Hwang said.
The power-generating property of the material was sustained and in tests over time the material did not leach. It also demonstrated a level of mechanical strength comparable to other materials used in dental applications.
Finally, the material did not harm normal gingival tissue in the researchers’ experiments, supporting the idea that this could be used without ill effect in the mouth.