Finite element analysis of bone around a dental implant supporting a crown with a premature contact

To investigate the influence of a premature contact caused by an implant-retained crown (IRC) on stress and strain distributions in bone surrounding the implant using the finite element method.

A 3D finite element (FE) model of a section of a mandible with a single tooth dental implant, an IRC, and two adjacent teeth was created. Three rigid plates were used to represent the antagonist teeth. Modeling the antagonist teeth using the rigid plates removed the necessity to create FE models for the antagonist teeth, their periodontal ligament, and the maxilla. Moreover, this new approach also allowed the premature contact height to be easily varied by changing the positions of the rigid plates. In the present study, premature contact heights of 0, 50, 100, 150, 200 and 250 microm were considered. The FE contact analysis was employed. All materials were assumed to be linear elastic and isotropic.

The magnitudes of von Mises stresses in the bone change drastically when there was a premature contact. For example, the von Mises stress increased from 9.68 MPa in the case with no premature contact to 49.92 MPa in the case with the premature contact height of 50 microm. In addition, the magnitude of the major principal strain in the marginal bone reached the pathologic overload of 4000 microepsilon when the premature contact height was 100 microm or higher.

The influence ofpremature contacts is very high and the premature contact height of an IRC over 100 microm should be avoided as much as possible to provide longevity of dental implants.