A 3-DIMENSIONAL, FINITE-ELEMENT ANALYSIS OF BONE AROUND DENTAL IMPLANTS IN AN EDENTULOUS HUMAN MANDIBLE

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 an entire lower jaw. This model was built from data obtained fr om slices of a single human mandible and was provided with two endosse ous implants in the interforaminal region. The implants were either co nnected with a bar or remained solitary, and were loaded with a horizo ntal bite force of 10 N, a vertical bite force of 35 N, or an oblique bite force of 70 N. The most extreme principal stresses in the bone we re always located around the neck of the implant. Stress around the im plant was, therefore, not only caused by the local deformation of the bone due to movement of the implant and interface relative to the surr ounding bone but also by the bending of the mandible. The most extreme principal stress was found with oblique bite forces. The highest maxi mum and lowest minimum principal stresses were 7.4 and - 16.2 MPa in t he model without the bar and 6.5 and - 16.5 MPa in the model with the bar. When differences in the amount of bite force were eliminated, the vertical bite force resulted in the lowest stress. Differences in the stress concentration between the model with and without a bar were sm all and the direction of the bite force had much more influence than t he connection of the implant abutments.