What are the three primary periods in tooth formation?
1. Initiation
Tooth development begins with the formation of the tooth germ, which consists of a group of cells that will form the tooth. The germ is located in the jawbone and is surrounded by a membrane. The tooth germ is made up of three layers:
- The ectoderm, which is the outermost layer, gives rise to the enamel, which covers and protects the tooth
- The mesoderm, which is the middle layer, gives rise to the dentin, which is the hard tissue underneath the enamel
- The endoderm, which is the innermost layer, which gives rise to the pulp, which is the soft tissue inside the tooth containing nerves and blood vessels
The tooth germ begins to develop at around 6 weeks of gestation.
2. Proliferation
Once the tooth germ has formed, it begins to proliferate and grow. The cells of the germ divide rapidly, and the tooth begins to take shape. The different parts of the tooth, such as the enamel, dentin, and pulp, begin to develop. The root of the tooth also begins to form during this stage.
The proliferation stage lasts from about 6 weeks to 6 months of gestation.
3. Maturation
During the maturation stage, the cells in the tooth stop dividing and begin to mature. The enamel hardens, and the dentin becomes thicker and stronger. The root of the tooth continues to grow, and the tooth erupts from the gum line.
The maturation stage lasts from about 6 months to 2 years of age.