This book is an overview of various catabolic biomarkers and the effect of catabolic biomarker like cathepsin in orthodontic tooth movement. It also emphasizes on orthodontic tooth movement, bone modelling and remodelling, osteoclastic differentiation, the role of G-CSF, M-CSF, GM- CSF during orthodontic tooth movement and markers associated with the root resorption during the orthodontic tooth movement.