Novel Mg-Ca-La alloys for guided bone regeneration: Mechanical performance, stress corrosion behavior and biocompatibility

Guided bone regeneration (GBR) is a therapeutic method that is used to augment deficient ridges before dental implantation. The non-absorbable membranes need secondary removal surgery, while absorbable collagen membranes fail while being applied to large bone defects because of their relatively low stiffness. The "ideal" membrane for use in GBR has yet to be developed. This study aims to develop and explore the feasibility of Mg-Ca-La alloys for application in GBR. Mg-0.2Ca-0.2La alloy exhibits fine microstructure and a good combination of tensile strength and ductility. Mg-0.2Ca-0.2La alloy is also capable of supporting the adhesion, proliferation and migration of human gingival fibroblasts, and shows good cytocompatibility on MC3T3-E1 cells. The GBR membranes usually need intraoperative bending or shaping to adapt the alveolar ridge. The additional effect of bending stress on magnesium-based materials must be considered due to a well-known issue, namely stress-corrosion cracking (SCC). The SCC results reveal that the bended Mg-0.2Ca-0.2La presents a uniform corrosion morphology with a corrosion rate of 0.09 mm/yr, which is 61% less than that of unstressed ones. Mg-0.2Ca-0.2La alloy possesses adequate strength and ductility, high biocompatibility and slow degradation under bending stress, contributing to adequate malleability and sustained spatial stability for membrane use.