In the United States, more than 3 million individuals have dental implants, which are used to replace teeth that have been lost due to decay, gum disease, or accident. When compared to dentures or bridges, implants are a significant step forward, fitting considerably more securely and intended to endure for at least 20 years. Patients’ expectations are not always met, with implants often having to be replaced after five to ten years owing to local inflammation or gum disease, requiring an expensive and intrusive surgery for the patient to have the implant replaced again. As a result, Geelsu Hwang, assistant professor at the University of Pennsylvania School of Dental Medicine with a background in engineering, developed an innovative new implant to solve the problem. Geelsu Hwang’s study on oral health problems is informed by his expertise in engineering.
According to Hwang, the new implant will include two important technologies. One such material is impregnated with nanoparticles and is resistant to bacterial colonization. The second is an implanted light source that may be activated by natural mouth movements such as chewing or brushing. This light source can be used to perform phototherapy. Hwang and colleagues describe their platform in a paper published in the journal ACS Applied Materials & Interfaces, as well as a paper to be published in the journal Advanced Healthcare Materials in 2020. Their platform could one day be integrated not only into dental implants, but also into other technologies such as joint replacements. “Phototherapy may be used to treat a wide range of medical conditions,” adds Hwang. “However, once a biomaterial has been implanted, it is not feasible to replace or recharge the battery that powers it. A piezoelectric material, which can produce electrical power from natural mouth movements, is being used to provide a light that may be used to conduct phototherapy, and we have discovered that it is effective in protecting gingival tissue from bacterial challenge when exposed to germs.”
Specifically, in the paper, the researchers looked into the material barium titanate (BTO), which has piezoelectric properties that can be used in applications such as capacitators and transistors, but has not yet been investigated as a foundation for anti-infectious implantable biomaterials due to its limited research. The researchers utilized discs coated with nanoparticles of BTO and exposed them to Streptococcus mutans, a major component of the bacterial biofilm responsible for tooth disease, often known as dental plaque, in order to evaluate its viability as a foundation for a dental implant. They discovered that the discs were effective in preventing biofilm development in a dose-dependent manner. Discs with greater concentrations of BTO were more effective in preventing biofilms from adhering to them. While previous studies had suggested that BTO could kill bacteria outright by generating reactive oxygen species through light-catalyzed or electric polarization reactions, Hwang and colleagues discovered that this was not the case due to the short-lived efficacy and off-target effects of these approaches, according to the researchers. But instead of attracting bacteria, the material produces a stronger negative surface charge that repels the organism’s negatively charged cell walls. According to the experts, it is probable that this repelling effect will continue for a long time.
In order to combat bacterial development for an extended period of time, Hwang explains, “we needed an implant material that was resistant to bacterial growth for an extended period of time.” The material’s ability to generate electricity was maintained, and tests conducted over time revealed that the substance did not leach. Additionally, it showed mechanical strength that was similar to that of other materials utilized in dental applications. Finally, in the researchers’ tests, the material did not cause any damage to normal gingival tissue, lending credence to the notion that it might be utilized in the mouth without causing harm.
The technology is a finalist in the QED Proof-of-Concept competition, which is part of the Science Center’s research acceleration initiative. Hwang and his colleagues will get assistance from specialists in the field of commercialization as one of 12 finalists. If the idea is selected as one of three finalists, the group has the opportunity to earn financing of up to $200,000. In the future, the team hopes to continue to refine the “smart” dental implant system, testing new material types and possibly even using asymmetric properties on each side of the implant components, one that encourages tissue integration on the side facing the gums and one that resists bacterial formation on the side facing the rest of the mouth, in order to achieve a more natural appearance. In the future, “we want to further improve the implant system and ultimately see it commercialized so that it may be utilized in the dentistry profession,” adds Hwang.