Molecular regulatory mechanism of tooth root development

The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last few decades, but root development remains not well understood. Here we review the root development processes, including cell fate determination, induction of odontoblast and cementoblast differentiation, interaction of root epithelium and mesenchyme, and other molecular mechanisms. This review summarizes our current understanding of the signaling cascades and mechanisms involved in root development. It also sets the stage for de novo tooth regeneration. Better understanding of tooth root development may hold the key to artificial tooth regeneration, suggest scientists in China and the US. Based on research published during the last decade, Xiao-Feng Huang of Capital Medical University, Beijing, and Yang Chai of the University of Southern California, Los Angeles, reviewed the molecular mechanisms operating during root formation. Following tooth crown formation in the gums, a collection of cells called Hertwig’s epithelial root sheath (HERS) grows around it. HERS triggers the development of dentin and cementum, both vital materials for healthy roots. HERS cells, however, disperse as the root grows. More research is needed to clarify the fate of these cells, as well as the genetic signaling between two types of dental tissue, the epithelium and mesenchyme. Full understanding of these processes could eventually lead to artificially triggered tooth growth in humans.