Regensburg 2007 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 35: SYBM Bioinspired Materials
MM 35.26: Poster
Thursday, March 29, 2007, 18:45–20:45, H16
The rate of bone renewal controls its mechanical behavior — •Davide Ruffoni1, Peter Fratzl1, Paul Roschger2, Klaus Klaushofer2, and Richard Weinkamer1 — 1Max Planck Institute of Colloids and Interfaces, Potsdam, Germany — 2Ludwig Boltzmann Institute of Osteology, Vienna, Austria
At the material level bone is a nano-composite consisting of collagen and mineral particles. A crucial factor for the mechanical behavior is the amount and distribution of mineral. Bone material evolves in time as the result of a remodeling and a mineralization process. In trabecular bone the presence of bone packets with different degrees of mineralization is characterized by a bell-shaped frequency distribution of the mineral content, called the bone mineralization density distribution (BMDD). A tailor-made continuity equation is developed to answer how the rate of bone deposition and bone resorption influence the time evolution of the BMDD. First, the steady state solution of the model equation enables the extraction of information on the mineralization kinetics taking the measured BMDD as starting point. Secondly, the knowledge of the mineralization kinetics can be used to predict the full time evolution of the BMDD. Increasing the remodeling rate causes a less mineralized and more heterogeneous mineral distribution. Conversely, when reducing the turnover the BMDD displays transiently a sharp peak corresponding to bone with an unusual uniformity in its mineral content. Later in time higher and less uniform mineralization distributions are attained. From a mechanical view point this suggests an evolution towards stiffer but more brittle bone.