Molecular Biology of Orthodontic Tooth Movement

The application of orthodontic forces to correct mandibular and maxillary teeth irregularities through alveolar bone remodeling involves a series of coordinated and regulated molecular and cellular events in the periodontium i.e. periodontal ligament (PL), alveolar bone (AB), cementum, and gingiva. The PL and AB are the two important structures which actively participate in bone remodeling in response to mechanical forces. The fibroblasts, osteoblasts, osteocytes, osteoclasts, odontoblasts, cementoblasts, chondrocytes and immune cells are the major cell types which play an interactive role in the remodeling process. Activation of these cells result in the production of several pro-inflammatory cytokines, growth factors, colonystimulating factors, transcription factors and other regulatory molecules which modulate cell growth, proliferation, migration, differentiation, gene expression and cell function. Recent it has been shown that the role of SOX 9 gene transcriptase, parathyroid hormone related peptide (PTHrP), Indian hedgehog (IHH) protein in orthodontic tooth movement orthopaedics is significant in understanding the molecular biology of orthodontic tooth movement orthopaedic forces in growth modification therapy. In this article, however, we review the major cellular and molecular sequence of events during orthodontic tooth movement, per se.