This study highlights the dynamic nature of the mesenchymal cells during tooth development from the bud to the bell stage. Condensing mesenchymal cells, labelled on either side of the developing tooth bud, move toward the presumptive roots forming an arc of cells under the dental papilla. These labelled cells take part in formation of the dental follicle, which contributes to both the tooth and its surrounding periodontium, including the supporting alveolar bone. This study, thus, physically links development of the tooth with the tissue into which it develops. The results obtained clearly indicate that the tooth organ is an entity comprising dental and periodontal tissue.