Orthodontic tooth movement (OTM) is a complex biological phenomenon involving bone and periodontal tissue. Numerous substances known as biomarkers are released from the dental tissues during this complex procedure leading to a series of biochemical reactions and ultimately orthodontic tooth movement. A thorough knowledge of these biomarkers is essential in order to understand the biological process of tooth movement. It is of advantage to the orthodontist to know the biological events that unfold during tooth movement because it varies from person to person .This review article presents a detail account of physiologic response to orthodontic force and the chemical mediators involved in this process.