Changes in articular eminence inclination during the craniofacial growth period

The articular eminence of the temporomandibular joint dictates the path and type of condylar-disk complex movement. It has been suggested that a steep articular eminence inclination may predispose to temporomandibular joint dysfunction. When using functional appliances in orthodontic therapy, the bite registration is greatly affected by the articular eminence inclination. Furthermore, the articular eminence morphology has been related to specific facial types. Knowledge of how the articular eminence inclination behaves during the craniofacial growth period could help establish more biological treatment modalities. We took silicone impressions of both left and right articular fossae from 90 dried skulls. This sample consisted of three equal subgroups of skulls, each group presenting a deciduous, mixed, or permanent dentition. After the impression had set, they were removed and cut into sagittal sections 2.5 mm thick. The three middle sections were photocopied and enlarged by 200%. The inclination of each section was calculated trigonometrically, and the mean value was assigned to the inclination of the respective eminence. The data indicated that the inclination of the articular eminence changes rapidly until the completion of deciduous dentition, attaining more or less 45% of its adult value. By the age of 10 years, it was 70%-72% completed, and by the age of 20 years, it was 90%-94% completed. In conclusion, normally, the articular eminence inclination shows a symmetrical growth pattern, and it grows at a very rapid rate, attaining almost half of its adult value by the age of two years.