LOADING CONDITIONS OF ENDOSSEOUS IMPLANTS IN AN EDENTULOUS HUMAN MANDIBLE - A 3-DIMENSIONAL, FINITE-ELEMENT STUDY

The design of dental superstructures influences the loading on dental implants and the deformation of the anterior interforaminal bone in an edentulous mandible. This deformation causes stress in the bone aroun d the implants and may lead to bone resorption and loss of the implant . The stress distribution around dental implants in an edentulous mand ible was calculated by means of a three-dimensional, finite-element mo del of the anterior part of the jaw. This model was built from data ob tained from slices of a single human mandible and was provided with fo ur endosseous implants in the interforaminal region. The implants were either connected with a bar or remained solitary. The solitary implan ts or the bars were loaded either uniformly or non-uniformly. In case of a nonuniform distribution, either the central bar or the central im plants were loaded or the lateral bars or the lateral implants were lo aded. The most extreme stresses in the bone were always located around the neck of the implant. In the case of the uniform distribution of t he loading there were more or less equal extreme principal stresses ar ound the central and lateral implants. If the load was not uniformly d istributed on the superstructure then the implant that was nearest to the place of loading showed the highest stress concentration; with con nected implants there was a reduction in the magnitude of the extreme principal stresses compared to solitary implants.