The role of the osteocyte in orthodontic tooth movement in the rat dento-alveolar complex.

Abstract

Since the middle of the 19th century the importance of mechanical stimuli in the maintenance and structure of skeletal tissues has been recognised.[1] It is now accepted that skeletal tissue is dynamic, incorporating cycles of bone resorption and bone formation; a process which helps to restore the skeleton while preserving its structural integrity.[2] This remodelling is organised by cells of the osteoblast and osteoclast lineage and involves a complicated network of cell-cell and cell-matrix interactions, systemic hormones, locally produced cytokines and growth factors.[3] Orthodontic and orthopaedic practice have much in common, in that both fields involve a fundamental understanding of bone biology, particularly the relationship that mechanical stress has on the various cell types found in bone. Mechanical strain on a tooth, as opposed to bone, is a more complicated phenomenon requiring changes in both the periodontal ligament (PDL) as well as the supporting alveolar bone, which are tissue types that house vastly different cell populations and remodelling characteristics. The signal transduction events that convert the mechanical strain to a molecular biological response, and subsequent remodelling of the supporting tissues, are yet to be fully elucidated.[3] Bone biologists have recently ascribed to the osteocyte a key role in this mechanotransduction, a role that was traditionally given to the osteoblast. A more fundamental understanding of the cellular and molecular elements that regulate and drive these events is not only pivotal in understanding how these processes occur but also needed for development of a means to control them to make orthodontic tooth movement more efficient.[4]