TLR2 and Peri-Implantitis: For example, the TLR2 pathway has been confirmed both in the pathogenesis of periodontitis and peri-implantitis (56, 57); LPS and TLR4 pathway has been widely studied for the regulation in periodontitis and peri-implantitis (43, 56); and also other PRRs pathways should be considered (47, 48).