A three-dimensional finite element study on two versus four implants in an edentulous mandible.

The difference in stress distribution in the bone around dental implants was determined under conditions where either two or four implants were placed in the interforaminal region of the mandible. The purpose was also to determine the influence of the height of the mandible on the stress distribution. The stress distribution around the implants was investigated using three-dimensional finite element models of the interforaminal region of two mandibles with two different stages of resorption. It was concluded that there is no reduction of the extreme principal stresses when the load is distributed over an increasing number of implants. There is a tendency for a gradual stress increase as mandibular height decreases.