Structure of Tooth - What are the different layers ?

The outermost layer in the structure of tooth is made up of enamel. It it's the hardest and most mineralised substance of the body. It's the visible part of the tooth. This layer of tooth is most susceptible to dental caries, attrition / non-carious cervical lesions and fracture. This layer can never regenerate. Repair by itself is impossible but possible only when the dentist intervenes. The main inorganic content of enamel is hydroxyapatite crystals. Inorganic content constitutes up to 96 percent and 4 percent of organic content.  

The structure underneath the enamel of the tooth is dentine. The organic content is more than enamel. Major part i.e. up to 60 percent of dentin is made up of inorganic content and rest by organic. This layer can generate reparative dentin. It's yellowish in colour. It's sensitive due to presence of dentinal tubules traversing from the pulp to the dentine. These dentinal tubules carry dentinal fluid. The caries process is more damaging here than enamel 

The innermost layer of the crown structure is pulp. This layer consists of nerves and blood vessels. Any damage to the enamel followed by to dentin if it reaches pulp, the tooth starts aching and further there is chances of loosing its vitality. The pulp and the dentine share a close relationship. The cells in these both layers are associated and function as a unit. Cell processes from pulp extend to dentin. The pulp can be called as connective tissue containing cells, ground substances, fibres, interstitial fluid, cellular components etc. The pulp receives blood and nerve supply through the apical foramen of the tooth. Apical foramen forms the apex of the tooth. It consists of major and a minor opening / diameter. Apical region of the root carries lot of significance 

The supporting structure surrounding the tooth are periodontal ligaments, alveolar bone. Tooth root is covered by cementum. The periodontal ligament consists of various fibres which anchors the tooth to the underlying and surrounding alveolar bone. Alveolar bone forms the socket for the tooth. The cementum in the root protects the dentin and the pulp. Any damage to the surrounding tissues of the teeth requires intervention of periodontist who is specialised in taking care of health and damage to these structures 

Take home message 

It's important to take care of tooth as well as surrounding structures since they work as an unit. Tooth is that tissue if once lost cannot be regained. Only prosthesis can be given as substitute but can never function as effectively as the natural tooth. 

Article by Dr. Siri P.B.