Bone stress distribution for three endosseous implants.

Axisymmetric finite element models of three geometries were evaluated: a serrated solid with a 2-degree taper and a rectangular cross section; a cylindrical screw-type solid; and a finned solid with a 1 degree 9' taper and a circular cross section. Ten moduli of elasticity ranging from 0.348 to 74.96 psi x 10(6) were used for each geometry. Contour plots of the resulting Von Mises stresses were used to study the changing stress distribution patterns within the surrounding cortical bone. The results indicated that the serrated geometry led to high-stress concentrations at the tips of the bony ingrowth and near the neck of the implant. Low moduli of elasticity emphasized these concentrations. The nontapered screw-type geometry had high-stress concentrations at the base of the implant when high moduli were studied and at the neck of the implant when low moduli were studied. The conclusion of this study was that a tapered endosseous implant with a high elastic modulus would be most suitable for dental implantology. However, the design must not cause high-stress concentrations at the implant neck that commonly cause bone resorption.