THE EXTENT OF MICROCRACKING AND THE MORPHOLOGY OF MICROCRACKS IN DAMAGED BONE

Strain-induced damage in bovine laminar bone has been examined using laser scanning confocal microscopy (LSCM). The specimens were loaded in a fluorescein solution, which penetrated the newly formed cracks in the specimen. The microcracking, and the larger cracking, induced by strain were very clearly visible. The microcracking occurred diffusely in regions of high strain (stress), but was particularly obvious in the vicinity of large machined stress-concentrators. The microcracking could be shown not to be artefactual, that is, it was produced by strain, and not by specimen preparation. The microcracking interacted with the structure of the bone, often having a wavy appearance related to the histology. Microcracks seemed to be particularly associated with the most highly mineralized parts of the bone. LSCM is a technique holding great promise for the investigation of the initiation and development of damage in mineralized hard tissues, and other translucent materials.