Abstract

Bone is maintained through a coupled process of bone resorption and formation, a process called bone remodeling. Old bone is removed and new bone is created. Bone remodeling consists of bone resorption by bone resorbing cells, osteoclasts, and formation by bone forming cells, osteoblasts. There are several theories about the mechanisms of bone remodeling, but all of these consider a unique governing equation for the whole process and they are typically based on a single phase continuum model of bone [1-4]. In this research, we consider bone as a mixture of matrix (solid phase) and fluid. Also, we consider only the first phase of the remodeling process, i.e., bone resorption. Bone resorption is considered as a chemical process between osteoclasts and matrix. Osteoclasts dissolve bone mineral by acid secretion that degrades the organic matrix [5,6]. Resorption occurs on the interface between the solid and fluid phases. In order to simplify the model, osteoclast is not considered as a third phase, but as an interface between matrix and fluid.