Estimate of the topographical variation in the determination of the porion point

Abstract

The correct localization of porion point is very impor- tant for Orthodontic evaluations. Objective: this study was to establish indicators for the correct localization of the anatomic porion and of the cephalometric porion. Methods: through 40 lateral cephalometric radiographs of both male and female young white Brazilian children patients with average age of 8.9 years old, which were obtained from files archives. The selected indicators were: the external acoustic meatus; the radiographic image of the cephalostat ear rods markers patented by the X-Ray Rotograph Plus™; the Frankfurt plane and the Pterygoid Vertical Plane (PTV). Results: The results sho- wed that with use of the patented ear rod the cephalo- metric porion was localized in average at 6.41mm from PTV and 6.49 mm from the Frankfurt plane, and there was positive correlation between anatomic porion and cephalometric porion (r = 0.9852). Conclusion: It can be concluded that the used ear rods shows the correct localization the porion point minimizing the distortions of the radiography evaluations.