Mechanical characterization of bovine periodontal ligament

This study is part of a research program that aims to develop a constitutive three‐dimensional model of the periodontal ligament (PDL) through the identification of pertinent material parameters. As part of this program, bovine PDL was utilized to establish stress‐strain responses under tensile and compressive loading conditions. Fresh bovine molars were secured, frozen and prepared to appropriate dimensional specifications. Bar‐shaped specimens that comprised portions of dentine, PDL and bone were produced. Push‐pull tests were conducted using a specifically constructed loading machine. Full range monotonic stress‐strain diagrams were generated. The effect of a rate increase on cyclic S–E diagrams was also determined. The influence of specimen thickness was expressed in terms of modulus of elasticity, strength, uniaxial maximizer strain, and strain energy density. The overall load‐response was heavily hysteretic in compression. On the tensile side, after a steep rise, the curve tended to flatten out asymptotically. Variations in rate that spanned four orders of magnitude had no effect on reciprocal load responses. The E‐modulus was in the 4–8 MPa range, the strength of the PDL was 1–2 MPa, the maximizer strain was at 45–60% and the strain energy density ranged between 0.3 and 0.4 MPa.