Peri-implant diseases are inflammatory lesions, which include peri-implant mucositis and peri-implantitis. Peri-implant mucositis is described as the presence of inflammation in the mucosa around implants without any bone loss. By contrast, in peri-implantitis, besides the inflammation in the peri-implant mucosa, loss of supporting bone is also seen. Diagnosis of peri-implant diseases require the use of gentle probing(0.2 ~ 0.3N) to identify the presence of bleeding on probing, probing depth and suppuration, both signs of clinical inflammation. Radiographs are required to detect loss of supporting bone. Baseline probing measurements and high quality, long cone periapical radiographs should be obtained once the restoration of the implant is completed to make possible longitudinal monitoring of peri-implant tissue.