Effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system / 华西口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To assess the effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system.</p><p><b>METHODS</b>Forty-five simulated roots in the same length, taper and diameter were made of polymethacrylate (PMMA). Then the wax patterns of post-cores were cast. Soft lining material was used to simulated periodontal ligament. And each specimen was embedded in acrylic resin and then fixed in a special jig on the universal load-testing machine. A compressive load was applied at a 90-degree angle to the long axis of the core until fracture, at a crosshead speed of 1 mm/min. The maximum of load and the displacement were recorded.</p><p><b>RESULTS</b>The mean values of load in root and post-core system were 148.033 N, 161.889 N, 168.667 N, 181.589 N, 194.622 N, and the mean values of displacement were 1.965 mm, 2.837 mm, 3.327 mm, 3.927 mm, 5.326 mm.</p><p><b>CONCLUSION</b>The fracture resistance and displacement of root and post-core system with the same quality and altitude periodontal ligament are associated with the thickness of periodontal ligament when the range of thickness is from 0.2 mm to 1.0 mm.</p>