ABSTRACT
Objective: To evaluate the elastic modulus of Beagle's periodontal ligament(PDL) by means of nanoindentation, and to help build constitutive model of PDL precisely. Methods: 24 cross sections were obtained from the tooth root of lower first molars of beagle dog. With nanoindentation, intrusion and unloading to PDL sites on different planes of long axial and in different directions on the same plane of tooth root were achieved, and the load-displacement curves were obtained, from which the elastic modulus was calculated and analyzed. Results: The elastic modulus of the beagle's periodontal ligament varied from 0. 452-1. 542 Mpa. There was no significant difference in elastic modulus of the beagle's lower first premolar PDL in relation to different planes of long axial, while significant difference was found in different directions (buccal/lingual sides and mesial/distal sides) on the same plane of tooth root(P＜ 0. 05). Conclusion: There was a difference in the elastic modulus of periodontal ligament in buccal/lingual sides and mesial/distal sides of the same tooth root.