Root development:
This occurs after the crown of the tooth is totally shaped. Once this happens, the tooth begins to erupt and therefore, the tooth starts to form from the top-down. The structure, which is actually responsible for the development of the root, is called the cervical loop. The cervical loop is the cervical most portion of the enamel (dental) organ. When the cervical loop begins to grow down into the dental sacs, it starts forming a Hertwig’s root sheath.
Root Dentin
The structure of the tooth’s root is composed by the dentin and cementum. Dentin is the substance, which is found between the enamel (also called the cementum) and the pulp chamber. The process of the formation of dentin is called dentinogenesis. The dentin starts forming when the outer cells of the dental papilla are induced into the differentiation into odentoblasts. This induction of differentiation occurs under the influence of the Hertwig’s root sheath. When the odontoblasts undergo dentinogenesis, they start secreting predentin. Once the dentin is formed, the basement membrane disintegrates along with the Hertwig’s root sheath
Cementum and Pulp formation
The formation of cementum is called cementogenesis, and this process occurs in the root area once the Hertwig’s root sheath has completely degraded. This disintegration of the sheath allows contact to occur between the dental sac cells and the dentin surface. During the process of cementogenesis, the cementoblasts start covering the root dentin. It is important to note that only when the cementoid has been completely mineralised can the cementoid be called cementum. The region where the cementum and the root dentin come in contact with each other is called the dentinocemental junction. Another thing to notice is that while the cementum is forming, the central cells of the dental papilla start forming the pulp as well.