Methodological Validation of the PIROP Ultrasound-Based System for Measuring Peri-Implant Soft Tissue Thickness in a Clinical Setting

<b>Background/Objectives:</b> Accurate and reproducible assessment of peri-implant soft tissue thickness is an important methodological aspect of contemporary implant dentistry, particularly in longitudinal studies evaluating soft tissue dimensions. While ultrasound-based techniques offer a non-invasive and quantitative approach, their validity in peri-implant settings remains insufficiently documented. The objective of this study was to validate the PIROP ultrasound-based system for measuring peri-implant soft tissue thickness by comparing it with a direct clinical reference method. <b>Methods:</b> Peri-implant soft tissue thickness was assessed at 40 planned implant sites at two predefined time points: prior to surgical incision and three months after closed healing. Measurements obtained using the PIROP ultrasound-based system were directly compared with measurements performed following surgical incision using a calibrated periodontal probe. <b>Results:</b> Overall, the relative differences between ultrasound-based and direct clinical measurements were small, indicating comparable performance under standardized clinical conditions. The PIROP ultrasound-based system demonstrated good agreement with the reference method, with high intraclass correlation coefficients (ICC = 0.86-0.88). <b>Conclusions:</b> Within the limitations of this methodological validation study, ultrasound-based assessment demonstrated good agreement with direct clinical measurements, supporting its use as a reliable, non-invasive, and quantitative measurement approach in clinical studies and longitudinal designs requiring repeated evaluation of peri-implant soft tissue thickness.