Load transmission in mastication

The anatomical set-up of the jawbone requires load transmission to be parallel rather than perpendicular to the masticatory forces. In natural teeth, the horizontal masticatory forces are converted into vertical forces. But this is only possible because natural teeth are anchored in the periodontium, a suspension system with fibres cushioning the masticatory load as it is transmitted to the surrounding bone where they arrive as tensile forces. Implants, by contrast, must pass the masticatory load to the bone without the benefit of this cushioning effect. Bone is not, however, homogeneous in the sense of being uniformly solid.

Resilience mechanisms at work with disk implants. Resilience in the area of the implant segment passing through the spongy bone when under pressure (left) compared to the resilience of the threaded pin at the centre of the bar attachment transversing the baseplate (right).