1 INTRODUCTION Peri-implantitis (PI), an inflammatory disease characterized by soft tissue infection and bone resorption, severely affects implant longevity and is the main cause of implant failure.1, 2 According to statistics, about 30% of implant patients suffered from PI.3 However, PI has no effective diagnosis or therapy since its pathophysiology is not fully understood.4 Thus, it is necessary to further consider the pathogenic mechanism of PI to provide new ideas for effective diagnosis...