Nanoindentation as a means for distinguishing clinical type of osteogenesis imperfecta

Due to abnormalities in basic bone building components (collagen and mineral), the intrinsic material properties of Osteogenesis Imperfecta (OI) bone were hypothesized to be degraded and correlated to clinical types. Nanoindentation techniques were used to compare intrinsic mechanical properties of OI types III and IV bone. Young’s modulus (E) and hardness (H) were measured using the Oliver–Pharr method. Analysis showed that no significant difference existed in Young’s modulus and hardness measurements. However, the ratio of E/H exhibited a significant decrease for OI type III bone tissue. Since the ratio is proportional to fracture toughness, the decreased E/H indicates less fracture resistance for OI type III, which is consistent to the clinical observation. The results of this study suggest that nanoindentation may serve as a means to distinguish clinical types of OI.