Issue # 12022
Javad Parvizi MD,
FRCS Rothman Orthopaedic Institute at Thomas Jefferson University in Philadelphia, PA
Combating Infection: The Role of Implant Materials in Orthopedics and Dentistry
In 1952, the Swedish anatomy professor Per-Ingvar Brånemark was investigating as young researcher the anatomy of blood flow. One of his experiments studying the microcirculation in rabbit bone tissue resulted in the discovery of osseointegration and the beginning of implantology. Our colleague’s original intention was to apply this finding to joint replacement, but then he turned his back on orthopaedics and dedicated his research to dental implantology.
It took a while before his research allowed a breakthrough. Still in 1974, the American Dental Association suggested that dental implants should not be used for routine clinical practice! History taught us that perseverance would reward Prof. Brånemark‘s efforts. Today, dental implantology records excellent outcomes, similar to what we see in hip or knee replacement. Together with this success, though, we also share a common enemy: bacteria.
Whereas orthopaedic surgeons fight against periprosthetic joint infection in hip and knee arthroplasty, dental implantologists face peri-implantitis and oral mucositis. Both disciplines can learn from each other in the battle against infection and understand the association between implant materials and host response.
Prof. Lia Rimondini is an expert in development and pre-clinical characterization of implantable biomaterials. As part of her research field, she explored the role of bacteria and biofilm formation on dental implant materials. She extended her research to orthopaedic implant materials and could confirm what she had discovered for oral implants: bacteria are generally more prone to adhere to metal than to ceramics. In other words, ceramics accumulate less biofilm than metal or even polymers. In her contribution Prof. Rimondini compares the behavior of bacteria and biofilm formation in both body regions.
Prof. Romanos is an implantologist and professor of dentistry. Routinely, he has long used titanium implants. Like many of his colleagues, he faces a high prevalence of inflammatory processes after implanting titanium implants. He has dedicated his life to investigating the mechanisms causing peri-implantitis and peri-implant mucositis. As in orthopaedics, the reasons are multifactorial. However, the advances in ceramic implantology and the improvement of ceramic materials convinced him that using ceramic could cause less plaque formation and less inflammation around zirconia implants. Current studies support his observations.
At Rothman, we routinely use ceramic heads in total hip replacement because our research has shown the impact of material on the risk of infection. At our institution, we compared the infection rates of our patients treated with metal-on-polyethylene (MoP) to those treated with ceramic-on-polyethylene (CoP) implants. Our findings, recently published in the Journal of Orthopaedic Research, show a significantly higher incidence of infection in patients with metal heads. We suspect that the reasons are multifactorial, but a specific mechanism related to leucocyte recruitment to metal implants can be an explanation.
More than ever, nurturing an interdisciplinary research culture with solid bonds between basic research and clinical research appears to be the key to understanding our patients and their comorbidities, and selecting adequate treatment for them.