Determination of stress patterns in root-filled teeth incorporating various dowel designs.

A theoretical investigation has utilized the finite element technique to analyze mechanical stress patterns in a reconstructed maxillary central incisor. A series of designs for endodontic dowel posts incorporated into prosthesis has been comparatively evaluated. For the load condition considered, the results show that minor changes in the stress patterns are produced by the post diameter, length, and taper variations considered. 1. In general, larger post diameters decrease the maximum stresses for both the cylindrical and tapered designs. Variation of diameters over a 15% range produced stress variations of about 8%. 2. The effect of post length on the highest stresses in bending was less than the diameter changes. The real effect of the length changes was to change the location of the stress concentrations that occurred at the post apex in all cases. 3. The effect of taper was found to be slight if the local tapered-post diameter was comparable to the cylindrical post diameter in the high-stress region. 4. For the load considered in this study, the tapered-post design experienced slightly higher tensile and slightly lower shear stresses than the cylindrical post. 5. Using the peak stresses in the dentin and at the dentin-post interface as a criterion, the cylindrical post with the largest diameter is the best design among those examined.