Delivery of ICG solution at a concentration of 1 mg/mL will be used. The photosensitizer will be applied until the bottom of the peri-implant pocket using a 1 ml syringe. An 810 nm diode laser (A.R.C. laser GmbH, Nurnberg, Germany) with a power of 200 mW (continuous mode) and total energy of 4 J will be used to excite the ICG by starting from the papilla for 30 s followed by the insertion inside the peri-implant pocket depth for 10 s from both buccal and lingual side moving to coronal direction.

Non-surgical peri-implant mechanical debridement (PIMD) through ultrasonic device with a carbon tip.

An 810 nm diode laser (A.R.C. laser GmbH, Nurnberg, Germany) with a power of 200 mW (continuous mode) and total energy of 4 J was used to excite the ICG by starting from the papilla for 30 s followed by the insertion inside the peri-implant pocket depth for 10 s from both buccal and lingual side moving to coronal direction. The treatment was applied according to the manufacturer's recommendation. The PDT was performed by a single operator in all test patients

Presence or absence of bleeding indicated as '1' or '0', respectively

Presence or absence of plaque indicated as '1' or '0', respectively.

Measurement of consecutive millimeter markings of the periodontal pocket depth

Presence or absence of pus

Measurement of consecutive millimeter markings of the alveolar bone levels

Bacterial viability from the peri-implant plaque

Bacterial viability from the peri-implant plaque