Immunological mechanism and research progress of peri-implant bone resorption

After implantation of implants as foreign bodies into the jawbone, the immune and skeletal systems of the body regulate and adapt to each other, promoting bone resorption and remodeling around the implants. The imbalance of foreign body response may lead to loss of bone around the implants. This article summarizes the relevant factors that may trigger peri-implant immune response and lead to bone resorption, including peri-implant microbial infection, implant overload, poor overall condition, and biological wear of implant materials. Osteoclasts are currently the only known cells in the human body that can cause bone resorption, so their generation has been used as a clue to sort out several key pathways and factors that regulate this process, such as macrophage polarization, receptor activator of nuclear factor-κB ligand (RANKL) / receptor activator of nuclear factor-κB (RANK) / osteoprotegerin (OPG) pathway and nuclear factor-κB (NF-κB) pathway. This review discusses the immune mechanism of peri-implant bone loss, providing insights for understanding the concept of osseointegration and treating peri-implant bone loss from an immune perspective.