Posterior growth and forecasting the development of mandibular third molars.

The inter-dependence of overall orthodontic treatment and the development of the third molars requires the entire dentition to be taken into consideration ab initio and for the patient to be fully informed as to the extractions involved. The anatomical conditions in which the development of the wisdom teeth can occur are studied using comparative samples, with and without third molar retention, followed up to the age of 20 years. Posterior growth observed between the beginning of multiband treatment and adulthood amounted to 11/16mm (girls/boys). The initial difference in forecasting the space between the groups with retained third molars and without was slight (5.5mm). However, this difference was maintained throughout the growth period and was sufficient to guide the final choice whether to extract these teeth or allow them to erupt.

[Three-dimensional 14 point-cephalometric analysis: compensation of maxillofacial dysmorphisms]. / Analyse céphalométrique tridimensionnelle à 14 points: compensations des dysmorphies maxillo-faciales.

The eight points cephalometric Treil model and the alveolodental parameters already allows an initial description of the maxillofacial framework and the teeth. Added six points allows taking into consideration an intermediate level: the maxillary and mandibular skeletal basis. So, the 14 points complete model allows a complete craniofacial anatomy description in three analysis levels: the framework or envelope, the osseous bases, the alveolodental arch. The correlation study between the 3D parameters at different levels defines the compensation notion. It allows understanding how skeletal disharmony may be distributed among the different levels. Only vertical direction compensations are analysed here.