An in-vivo preclinical study assessing biocompatibility of Pd-based bulk metallic glass Pd₇₉Ag_(3.5)P₆Si_(9.5)Ge₂

Background: The bulk metallic glass (BMG), Pd₇₉Ag_(3.5)P₆Si_(9.5)Ge₂, has a high fracture toughness and has been found to accommodate post-yield stress, unlike most other BMG. Moreover, due to its greater noble gas composition it has a intrinsic corrosion resistance, ideal for dental and orthopedic implants. Objective: This present study aimed to evaluate the in vivo application of Pd₇₉Ag_(3.5)P₆Si_(9.5)Ge₂ in a large translational sheep model to assess its efficacy to be utilized as an endosteal device. Methods: Twelve implants in the form of cylindrical rods (3 mm in diameter) were produced through rapid quenching. Each sheep (n = 12) received one osteotomy in the mandibular region using rotary instrumentation, which was filled with Pd₇₉Ag_(3.5)P₆Si_(9.5)Ge₂. After 6- and 24-weeks the animals were euthanized, and samples collected en bloc to conduct histomorphometric analysis. The degree of osseointegration were assessed through bone-to-implant contact (BIC). Results: All samples revealed favorable BIC along with with fibrous connective tissue layers at both 6- and 24-weeks. Bone along with interfacial remodeling was observed in proximity with the metallic glass surface at 6 weeks with higher degrees of bone organization being observed at the later healing time, 24 weeks. Conclusions: The synthesized BMG, given its unique combination of toughness and strength, revealed potential to serve as an alternative to commonly used Ti alloys.