Tooth formation

We call Odontogenesis the embryonic process by which the cells of the stomodeum or primitive mouth differentiate to give rise to teeth.

This life cycle of the dental organs includes a series of chemical, morphological and functional changes that begin in the sixth week of intrauterine life (approximately forty-five days of pregnancy) and that continue throughout the life of the tooth.

The process consists of several stages or stages, a total of five. The first is called the laminar phase. It is followed by four dental phases (bud stage, cap stage, bell stage and mature stage).

The laminar phase coincides with the differentiation of the cells of the dental laminae from the ectoderm of the stomodeum. In these dental plates the dental primordia or buds will be formed. From here the future teeth go through the different stages of differentiation.

The sprout or bud stage consists of the appearance of ten thickenings in each dental lamina (future dental arch) which are the primitive stages of deciduous teeth. First, the lower or mandibular ten appear. At the end of intrauterine week 8, the upper ten or maxillary process has already finished.

The cap stage coincides with the modeling of the future dental crown, which takes the shape of a cap in this phase. From the buds or shoots, the enamel organ will be differentiated in the outer layer of the cap and inside it the dental papilla begins to differentiate, which will give rise to the pulp and dentin.

The so-called dental sac, future cementum and periodontal ligament of the tooth are formed around the cap.

At the end of this stage we can introduce the term dental germ or set of enamel, dental papilla and dental sac.

The bell stage is characterized by the differentiation of cells that will give rise to enamel and dentin.

At approximately week 10 of intrauterine life we ​​find the deciduous teeth in the bell phase and the permanent teeth in the bud phase.

The tooth formation process comes to an end coinciding with the eruption phase and consists of the formation of its root.

It would be interesting to introduce and differentiate the concepts of rash and exfoliation.

We call an eruption the migratory process that the tooth undergoes from its place of formation (inside the bone) to its positioning in the oral cavity. It includes the concept of emergency or specific moment in which the tooth bursts into the gum and can already be seen in the oral cavity.

The concept of exfoliation refers to temporary teeth and refers to their physiological loss after their function has ended. This is preceded by the physiological reabsorption of the root. This space is gradually being occupied by the definitive tooth, which will end up occupying the space of the exfoliated temporary tooth.

The root of the final tooth will not be fully formed until 24 months after its eruption.

The deciduous denture is usually complete in children between 2'5 and 3 years of age and consists of 20 teeth, 10 in each arch (2 central incisors, 2 lateral incisors, 2 canines, 2 first molars and 2 second molars).