Photosensitizers as potential culprits for compensatory benefits of aPDT in the treatment of peri-implantitis: Unraveling the fundamental knowledge and bounded clinical applications of the aPDT.

Peri-implantitis is an inflammatory disease triggered by a dysbiotic biofilm on dental implants, leading to bone loss and potential implant failure. Although nonsurgical and surgical treatments can reduce the inflammatory process, the high prevalence of peri-implantitis suggests that these interventions are not always effective in arresting disease progression. This has prompted increased interest in antimicrobial photodynamic therapy (aPDT), which utilizes photosensitizers (PSs) activated by light to target bacterial infections. Despite promising benefits, aPDT has not yet achieved consistently favorable clinical outcomes. It may be due to the limitations of current PSs, including restricted light activation, insufficient tissue penetration, and variable antimicrobial efficacy. Additionally, the stability and selectivity of PSs are crucial for their effectiveness against pathogenic bacteria. Variations in light delivery systems and treatment protocols may also contribute to inconsistent results across studies. This review will address the clinical challenges of aPDT for peri-implantitis, critically analyzing the shortcomings outlined in existing literature. It will further explore the chemical and biological mechanisms of PSs, providing insight into the underlying causes of clinical limitations. Finally, we will discuss potential improvements in PS compounds and treatment protocols that could enhance the therapeutic potential of aPDT, offering new perspectives on its role in managing peri-implantitis.