Peri-implantitis

Immune responses in the peri-implant soft tissue barrier are independently worthy of mention because they are distinctly different to these around teeth. One of the most major advancements in our understanding of bone remodeling and inflammatory peri-implantitis around dental implants comes from the findings that titanium material breakdown can cause immune activation in the peri-implant tissues. It was recently shown that while titanium implants are extremely resistant to corrosion in atmospheric conditions, if these surfaces are abraded such as during dental hygiene procedures with metal instruments, the environment in the peri-implant crevice with the pH fluctuations, bacterial reducing activity and tribocorrosion all contribute to the release of titanium particles (Figure 17a). These titanium particles are in the submicron and micron range and activate macrophages and multiple other phagocytic and non-phagocytic cells to elicit pro-inflammatory responses. Thus by acting as an environmental threat these particles alter the local microenvironment both with direct effects, such as IL-1β and RANKL upregulation as well as indirect effects through the change of the local conditions that affect microbiome composition (Figure 17b). As a result immune surveillance in the peri-implant soft tissue barrier is modified by the presence of titanium and results in a different clinical response, which is consistent with the much more rampant tissue destruction in peri-implantitis as compared to periodontitis as well as the resistance to antibiotic and scaling treatments. This new data have paved the way for immunomodulatory treatments for peri-implantitis that may be impactful in its management.

Figure 17a.

Figure 17a.

Figure 17b.

Figure 17b.

Beyond Pathogen-associated Molecular Patterns and Understanding Exposomes

Exposomes refer to the totality of environmental non-genetic exposures an individual encounters throughout their lifetime, encompassing all external factors that can influence health. These exposures range from chemical pollutants and dietary components to physical agents and biological factors. One key example of exposomes in periodontitis is smoking, which has profound multilevel effects on immune system responsiveness. New information suggests that titanium particles released from dental implants are a specific example of how the exposome can affect disease progression in peri-implantitis.³³ It is now well established that titanium particles are most often present in large concentrations in peri-implantitis, which suggest that titanium implant breakdown is one of the corollaries of this disease.³⁴

When titanium particles are released into the surrounding tissues, they can disrupt the normal functioning of the immune system.³³ One way how this can happen is via epigenetic modifications in which the particles are associated as an environmental factor.³⁵ Another possibility is that they alter the immune microenvirnoment by interfering with the way immune cells recognize and interact with pathogen-associated molecular patterns (PAMPs). For example, titanium particles activate the inflammasome, which is a multimeric intracellular assembly responsible for responding to PAMPs, and is responsible for the activation of IL-1β that is a potent pro-inflammatory mediator.^36,37 This disruption can lead to an altered immune response, characterized by increased inflammation and potentially contributing to hyper-activation of preosteoclasts that lead to clinical bone loss.³⁷ Thus, titanium particles from dental implants are not merely physical debris but represent a form of environmental exposure that can impact immune system dynamics and overall health.