Abstract

ABSTRACT

Introduction: Freeze-dried bone has increasingly affirmed its importance as a potential grafting material in the treatment of periodontal defects and holds promise for broader applications in orthopedic trauma and spinal surgery. International studies have demonstrated the superior efficacy of freeze-dried bone in promoting bone regeneration compared to various other graft materials. However, to ensure the quality and biological safety of this material—especially after sterilization via irradiation—developing an optimal preservation protocol is essential. In Vietnam, research on the preservation standards of irradiated freeze-dried bone remains limited. Therefore, establishing a scientifically sound, effective, and context-appropriate preservation process is an urgent requirement to enhance the clinical utility of this graft material.

Objective: To develop a processing protocol for irradiated freeze-dried allogeneic bone.

Materials and Methods: The study involved 40 samples of allogeneic human bone obtained from legally authorized donors. Following initial processing steps designed to remove unwanted components and ensure biosafety, the bone samples were subjected to freeze-drying and gamma irradiation for sterilization. These samples were then assessed for quality, stability, and biological properties under various storage conditions.

Results: The study demonstrated that the freeze-drying process combined with gamma irradiation at a dose of 25 kGy achieved absolute sterilization, with a 100% sterility rate post-irradiation. Furthermore, the mechanical and biological properties of the material were maintained at acceptable levels when irradiation was performed under low-temperature conditions. The residual moisture content after freeze-drying was below 6%, meeting long-term storage standards. Strict control of processing and storage conditions proved to be crucial in maintaining graft quality, providing a scientific foundation for establishing standardized protocols for clinical application in Vietnam.

Conclusion: This study successfully developed a feasible processing protocol for irradiated freeze-dried allogeneic human bone under conditions relevant to Vietnam. The protocol includes sterile handling, cleaning with hydrogen peroxide and ultrasonic washing, freeze-drying at –60 °C to achieve residual moisture below 6%, followed by gamma irradiation at a standard dose of 25 kGy. The results confirm that this protocol ensures both effective sterilization and preservation of essential mechanical and biological properties.

Keywords: Freeze-dried bone, irradiation, moisture content, rehydration.