Correspondences of hydrostatic pressure in periodontal ligament with regions of root resorption: A clinical and a finite element study of the same human teeth

The main objectives of this study were to generate individual finite element models of extracted human upper first premolars, and to simulate the distribution of the hydrostatic pressure in the periodontal ligament (PDL) of these models for evaluation of the risk of root resorption. The individual extracted teeth were from a previous in vivo study that investigated root resorption after application of continuous intrusive forces. The results of experimental examination and simulations were compared on these identical tooth roots. The applied force system was 0.5 N and 1.0 N of intrusive force. The simulated results during intrusion of 0.5 N showed regions near the apical thirds of the roots with hydrostatic pressure over the human capillary blood pressure. These regions correlated with the electron microscopies of previous studies performed in Brazil with the identical teeth. An increased force of 1.0 N resulted in increased areas and magnitudes of the hydrostatic pressure. The key parameter indicating beginning root resorption used in this study was an increased value for hydrostatic pressure in the PDL.