Evaluation of Hydration Protocols for Human Cortical Mineralized Particulate Allografts

Objective: Bone graft hydration is a critical yet under-explored factor influencing the handling and performance of allograft materials in regenerative procedures. Most manufacturers suggest that biomaterial should be hydrated for at least 30 minutes before use. However, despite widespread clinical use, no standardized hydration protocol exists, and the impact of hydration on the chemical composition, mineralization, and structural integrity of graft materials remains unclear. This study aims to evaluate the physicochemical alterations of mineralized particulate bone grafts following hydration at varying concentrations and time points. Methods: Three commercially available human allograft materials {Straumann Mineralized (SM), Geistlich Mineralized (GM), and Zimmer Mineralized (ZM)} from three different manufacturers, with particle sizes ranging from 250–1000 µm, were examined. The granules were hydrated in 0.9% saline at concentrations of 50 µL and 500 µL and incubated for 1, 10, and 30 minutes. Scanning Electron Microscopy (SEM) was employed to assess hydration-induced structural changes. Chemical composition and molecular alterations were analyzed using Fourier Transform Infrared (FTIR) Spectroscopy and spectral data were processed using second-derivative analysis to improve peak resolution, allowing for the quantification of vibrational bands. Results: SEM analysis revealed no significant differences in surface morphology of the mineralized grafts after hydration. FTIR analysis showed chemical homogeneity across graft materials, with variations in peak intensities reflecting differences in molecular concentrations, mineralization, and collagen integrity. Biomaterial hydration promoted significant selective spectral band increases for all the time points evaluated. Prolonged hydration times did not produce significant or proportional spectral shifts, suggesting a saturation threshold after 1 minute of hydration. Conclusions: Increasing hydration time did not result in significant changes in vibrational bands, suggesting that hydration times longer than 1 minute have minimal impact on the molecular structure of the particulate allografts evaluated.