FE Analysis of Endodontically Treated Teeth With Coronoradicular Stabilization Posts

OBJECTIVES: To determine the relative effects of coronoradicular stabilization post material and post design on the stress distribution in endodontically treated teeth. METHODS: A freshly extracted maxillary central incisor was endodontically treated and scanned using micro-CT (Skyscan1172, Microphotonics) to build 3D finite element models according to the type of post used for coronoradicular stabilization: quartz fiber-reinforced double taper (FDT), quartz fiber-reinforced two-stage (F2S), zirconia double taper (ZDT), and zirconia two-stage (Z2S). The tooth was obturated using the Epiphany (Pentron) system and finished with a composite core (CLEARFIL PHOTO CORE, Kuraray) and ceramic crown (ProCAD, Ivoclar-Vivadent) cemented with Panavia F 2.0 (Kuraray). ScanIP (Simpleware) was used to create masks for the components by thresholding based on radiolucency. Reinforcing posts were constructed using Boolean operations on CAD primitive elements and were electronically implanted in the tooth model using ScanCAD (Simpleware). The elastic properties of each component were measured using an ultrasonic pulse apparatus (25DL Plus, Panametrics). ScanFE (Simpleware) was used to assign the material properties and transfer the models to ANSYS (DRD) for load application and solution. Loading was applied 3mm below the incisal edge on the palatal surface at 45-degrees to the long axis. RESULTS: The maximum stress was predicted to be in the dentin near the CEJ with normalized magnitudes of 0.556 (FDT), 0.437 (F2S), 0.551 (ZDT), and 0.425 (Z2S). The maximum stress predicted for the post was on the post surface adjacent to the CEJ with normalized magnitudes of 0.051 (FDT), 0.054 (F2S), 0.299 (ZDT), and 0.329 (Z2S). CONCLUSION: Maximum stress was predicted to be in the dentin and to be highest for teeth reinforced with double taper posts. Stress levels in the dentin and post were most similar for teeth reinforced with zirconia posts. Supported by grants from the Egyptian Embassy (JS2190) and the NIH-NIDCR (DE013358 and DE017991).