Tooth development is an intricate process. The beginning of this process starts in the embryonic stage, when the embryonic cells grow in a certain pattern. These will later sprout into the oral cavity, forming your teeth. Just like animals, the vertebrate species also develop teeth, which likely have the same tooth development as humans. And similar to hair, these are appendages that grow out from beneath the skin. The formation of cells and biological archetype matches those of the hair and glands in the embroyonic stages.

During the fetal stage of development, enamel, dentin, cementum and peridontum begin to form in certain stages. In the sixth and eight week, primary or ‘baby’ teeth start to sprout out. The permanent teeth will develop in the twentieth week. However, if these do not develop within the given range, it may never develop at all. Human teeth need a healthy oral environment for it to grow.

Maturity of Teeth

The interaction of ectoderm and mesenchyme tissues triggers the maturation of your tooth. Ectoderm found in the oral cavity condenses into buds, which fold into a crown of the tooth. The interaction of the epithelium (protective sheath) and mesenchymal tissues is an intricate process that follows a certain pattern making up the morphology of the teeth.

Stages in Tooth Development

There are four key stages in tooth development: Bud stage, the cap, the bell and maturation. It is, however, hard to classify these stages considering different parts are involved in the same tooth with varying stages of development at similar times.

Bio-Signaling in Tooth Development

According to Theslef, the maturation of tooth development is due to the signals being sent and received from one stage to another or from a set of cells to another set of cells. In the exact pattern, these signals are constantly recurring which eventually lead to the eruption of a tooth. The recurrent signals between the masenchyme cells and the ectoderm will then lead to the development of a tooth.

In the tooth development levels, Pracrine signals these ‘go between’ molecules in various cells and tissue layers. There are three categories of signal molecules: Transforming Growth Factor or TGfb, Fibroblast Growth Factor or FGC and the Hedgehog and Wnt group. These signal molecules communicates for the epithelium and mesenchyme cells and will also relay signals to tissue layers. With repetitive signals, these cells will interpret it and then relay it the next cell in the same pattern.

The most common feature in the maturity of a tooth is the brief signal centers in the epithelium in the first stages. Within the three groups, there were different signals that are being passed which are: SHH (sonic hedgehog) and numerous BMPs (Bone Morphogenetic proteins from the TGFbeta group), FGFs and Wnts that are passed at the same time.

The primary signals are being given off during the epithelial budding stage. From there, the enamel knot will signal to take over to form the cap stage. This enamel knot will modulate the maturation of the tooth crown and then control the secondary enamel knots where the epithelial folds form a cusp.

In the initial stages of tooth maturation, the epithelium sends BMP and FGF to the odontogenic mesynchyme. This will in turn send signals to furthermore relay maturation of tooth.

The structure of the enamel knot signals relays signals indicating its position. This would also send molecular signals like FGF, BMP, Hedgehog (Hh) and Wnt signals. The epithelium and mesenchyme cells will then pick up these relayed signals to develop the tooth further.

In humans, eruption of a tooth is a course of development wherein the teeth sprouts out in the mouth, making it visible.