ABSTRACT
Dental implants are of considerable importance for the treatment of partially or completely edentulous patients. In the case of an edentulous mandible, the use of a over-denture supported by only two implants can improve the masticatory function and help prevent the further atrophy of the proximal alveolar ridge.
In this study a 3D inhomogeneous voxel model of an edentulous mandible with two ITI dental implants was created based on CT scans.
The loading was determined by in vivo measurements of the 3D forces on the implants in five patients with implants successfully osseointegrated for more than five years. For this purpose the patients were fitted with special suprastructures on their implants with integrated three dimensional load measuring piezoelectric transducers. Loads were registered for maximum bilateral and unilateral biting as well as for several functional activities such as chewing of bread, grinding or tapping.
The measured loads were then imposed on the implants in the model together with loads directly imparted from the prosthesis onto the alveolar ridge.
The results indicate that the non-vertical components of the loads on implants must not be neglected, which reach values of 30–50 % of the vertical components. The highest loads found on the implants were located in the medio-frontal area where the implants penetrate the cortical bone. With respect to the overall loading of the mandible a relatively even distribution of stress and strain was found over the whole bony structure, indicating the functional adaptation for chewing and biting.
