The implant infection paradox: why do some succeed when others fail? Opinion and discussion paper

• Published in: European cells & materials 2015-06, Vol.29, p.303-10; discussion 310-3
• Main Authors: Yue, C, Zhao, B, Ren, Y, Kuijer, R, van der Mei, H C, Busscher, H J, Rochford, E T J
• Format: Article
• Language: English
• Subjects: Bacteria - classification; Bacteria - drug effects; Bacteria - growth & development; Biocompatible Materials - chemistry; Biocompatible Materials - therapeutic use; biofilms; Dental Implantation - methods; Dental Implants - standards; host; Humans; immune responses; Immunity, Mucosal - immunology; Implant infection; infection risk; Models, Biological; Mouth Mucosa - immunology; Mouth Mucosa - microbiology; pathogens; Prostheses and Implants - classification; Prostheses and Implants - standards; Prosthesis-Related Infections - immunology; Prosthesis-Related Infections - microbiology; Prosthesis-Related Infections - prevention & control
• ISSN: 1473-2262; 1473-2262
• DOI: 10.22203/eCM.v029a23

Biomaterial-implants are frequently used to restore function and form of human anatomy. However, the presence of implanted biomaterials dramatically elevates infection risk. Paradoxically, dental-implants placed in a bacteria-laden milieu experience moderate failure-rates, due to infection (0.0-1.1%), similar to the ones of joint-arthroplasties placed in a near-sterile environment (0.1-1.3%). Transcutaneous bone-fixation pins breach the immune-barrier of the epidermis, exposing underlying sterile-tissue to an unsterile external environment. In contrast to dental-implants, also placed in a highly unsterile environment, these pins give rise to relatively high infection-associated failure-rates of up to 23.0%. Herein, we attempt to identify causes as to why dental-implants so often succeed, where others fail. The major part of all implants considered are metal-made, with similar surface-finishes. Material choice was therefore discarded as underlying the paradox. Antimicrobial activity of saliva has also been suggested as a cause for the success of dental-implants, but was discarded because saliva is the implant-site-fluid from which viable bacteria adhere. Crevicular fluid was discarded as it is largely analogous to serum. Instead, we attribute the relative success of dental-implants to (1) ability of oral tissues to heal rapidly in the continuous presence of commensal bacteria and opportunistic pathogens, and (2) tolerance of the oral immune-system. Inability of local tissue to adhere, spread and grow in presence of bacteria and an intolerant immune-system are identified as the likely main causes explaining the susceptibility of other implants to infection-associated failure. In conclusion, it is the authors' belief that new anti-infection strategies for a wide range of biomaterial-implants may be derived from the relative success of dental-implants.