Mixed dentition

It is a very long stage that ranges from 6 to 12 years and based on dental replacement (exfoliation of the temporary teeth and eruption of the definitive one). It is a period of transition and coincidence of temporary and permanent teeth in the mouth. At the end of this stage of dental coexistence, the temporary or milk teeth will have disappeared and the mouth will be occupied by the permanent but not yet complete dentition.

The replacement of the incisors (commonly known as blades) is a process eagerly awaited by the parents and the child, however the eruption of the first permanent or permanent molar that occurs simultaneously loses prominence.

The chronology of the eruption of permanent teeth would be as follows:

• First molars: 6 years

• Central incisors: 6-7 years the lower ones and 7-8 the upper ones

• Lateral incisor: 7-8 years the lower ones and 8-9 the upper ones

• Canines: 9-11 the lower ones and 11-13 the upper ones

• Upper and lower first and second premolars: 10-12 years

• Second molars: 11-12 years

Small deviations from the averages are a frequent cause of concern for parents. Any notable alteration in the chronology, as well as a striking asymmetry in the eruptive process of the same arch (understanding between homologous pieces on both sides of the arch), would be cause for consultation.

It should be noted that a delay or precociousness in the appearance of the primary dentition in the baby is also usually associated with a delay or precocity in the replacement towards the permanent dentition.

At the time of exfoliation or loss of the last milk tooth in a mouth, the mixed dentition period ends to give way to the permanent dentition, although at that age (approx. 12 years) there will still be some permanent teeth to erupt.

In order for a temporary tooth to exfoliate, a physiological process called "bone resorption" must first occur in which the root gradually loses until it loses its anchoring point in the bone and is definitively exfoliated. In most cases, the time it takes for a temporary tooth to be replaced by its permanent counterpart usually ranges from 0 to 5 months.