The control group was given ultrasonic subgingival curettage. With Swiss EMS ultrasonic therapy instrument, both the operator and the patient should wear safety goggles before operation. After the operator guides the patient to gargle, the mouth opener should be placed to perform ultrasonic subgingival curetting. The debridement time of the implant area should be controlled within 6 minutes, and the debridement time of other sites should be 5 s.

Given glycine subgingival sandblasting group glycine subgingival sandblasting group. Swiss EMS ultrasonic therapy instrument and EMS glycine sandblasting were used. Before the operation, both parties should wear safety glasses and place the mouth opener after the patient gargled. The location of sandblasting was selected to be 1-2 mm below the gingiva. During the operation, the time of sandblasting in the planting area should be controlled within 10 minutes, and then the time of sandblasting at other sites with the same amount of water and power should be controlled within 5s. After sandblasting, the patient's mouth was continuously rinsed with normal saline for 20s. After the operation, the patient was informed of the precautions after the operation, and the patient was instructed to master the correct oral maintenance method, pay attention to maintaining the cleanliness around the implant, and adhere to regular periodontal maintenance.

Given glycine subgingival sandblasting group glycine subgingival sandblasting group. Swiss EMS ultrasonic therapy instrument and EMS glycine sandblasting were used. Before the operation, both parties should wear safety glasses and place the mouth opener after the patient gargled. The location of sandblasting was selected to be 1-2 mm below the gingiva. During the operation, the time of sandblasting in the planting area should be controlled within 10 minutes, and then the time of sandblasting at other sites with the same amount of water and power should be controlled within 5s. After sandblasting, the patient's mouth was continuously rinsed with normal saline for 20s. After the operation, the patient was informed of the precautions after the operation, and the patient was instructed to master the correct oral maintenance method, pay attention to maintaining the cleanliness around the implant, and adhere to regular periodontal maintenance.

Change in Plaque Index (PLI; scored 0-3) from baseline to 3 and 6 months post-treatment, comparing subgingival sandblasting (glycine/erythritol) versus standard ultrasonic curettage. Higher scores indicate greater plaque accumulation.

Change in Bleeding Index (BI; scored 0-3) from baseline to 3 and 6 months post-treatment, comparing interventions. Higher scores indicate more severe gingival bleeding.

Change in Probing Depth (PD; measured in millimeters) from baseline to 3 and 6 months post-treatment, comparing interventions. Deeper pockets indicate worse peri-implant inflammation.

Change in pro-inflammatory cytokine levels measured in peri-implant crevicular fluid via ELISA across treatment groups.

Incidence of peri-implant inflammation recurrence (PD ≥5mm with bleeding/suppuration) in treated patients.