The periodontal ligament (PDL) is a very unique structure as it is the only soft tissue in the entire complex of the teeth and jaw bone. Being the only soft tissue it has a major role in controling the bone remodeling process and therefore tooth movement. In our recent research we showed that the 3D structure of the collagen network within the PDL is not uniform and are organized in sparse and dense networks. Non uniformity in ligaments is usually associated to pathological events and remodeling of the PDL is associated to loads however we found that the different networks are preprogrammed to begenerated according to the loads pattern designed for a specific tooth. This finding implicates that there is an internal force in the PDL that directs tooth movemet. This project is aimed at understanding the correlations betwwen external forces, internal forces and the PDL structure.  In order to do so we are combining clinical manipulations, powerful imaging methods such as high resolution microCT, multiphoton microscopy, electron microscopy, 3D image analysis algorithms and protein analytical tools.