[First orthodontic consultation: children or teenagers?].

Orthodontic treatments aim at improving the positions of teeth, the form of dental arches and their reports relations. Determining the age to perform these treatments consists in defining the ideal moment to achieve them in the shortest time possible and with the best stability success. To know when to address the child or the teenager to the orthodontist, it is necessary for the pediatrician to observe the patient, his/her positions, orofacial functions (phonation, swallowing, aeration), his/her face and profile, oral cavity, particularly the way his/her teeth articulate in the three spatial directions.

[Interceptive treatment with the DAC appliance: structural analysis].

The aim of this retrospective short and middle term study was to evaluate dental and skeletal effects during early class II treatment. Thirty subjects were treated with DAC appliance, 32 children were not treated. Data were collected at the start of the study (t(1)), after the active treatment (t(1')) and 28 months after t(1) (t(2)).

[Twins and the heritability of dentofacial phenotype].

In orthodontics and dentofacial orthopaedics, where genetic and environmental factors interpenetrate from the early stages of development, the clinician tries to determine how mechanics could influence patient's growth pattern. Comparing monozygotic and dizygotic twins, in their similarities and their differences, gives some answers..

[Known gene interactions as implicated in craniofacial development].

Many genes intervening in development, morphogenesis and craniofacial growth have been identified, primarily by the use of mice mutants. We can distinguish two families: the signalling factors and the transcription factors. The latter interact with DNA to activate or to inhibit the expression of other genes.