Implants allocated to this group will receive non-surgical peri-implant therapy after temporary removal of the prosthetic crown. The crown will be unscrewed before treatment to allow direct access and full visibility of the implant surface and peri-implant tissues. Mechanical debridement will then be performed under local anesthesia using sonic and ultrasonic devices with dedicated thin tips and Gracey curettes, according to the EFP S3-level clinical practice guidelines. After completion of debridement and biofilm removal, the prosthetic crown will be reinstalled. Patients will receive oral hygiene instructions and reinforcement.

Implants allocated to this group will receive non-surgical peri-implant therapy with the prosthetic crown left in place. Mechanical debridement will be performed under local anesthesia using the same instruments and protocol as in the test group (sonic scaler, ultrasonic devices, and Gracey curettes), but with access limited by the presence of the restoration. Professional oral hygiene instructions and reinforcement will also be provided.

In this group, the prosthetic crown will be temporarily removed before treatment to allow direct and complete access to the peri-implant tissues and implant surface. After local anesthesia, a thorough mechanical debridement will be performed up to the bottom of the peri-implant pocket using sonic scalers, piezoelectric/ultrasonic devices with dedicated thin tips, and Gracey curettes. The absence of the crown enables improved visualization, more effective instrumentation, and more accurate disruption of the submucosal biofilm. At the end of the procedure, the prosthetic crown will be repositioned. Standardized oral hygiene instructions and motivation will be provided. This intervention aims to maximize cleaning efficacy by eliminating prosthetic-related access limitations.

Change in mean peri-implant probing depth (PIPD) at the implant level (measured at 6 sites per implant) from baseline to 3, 6, and 12 months after crown removal.