Weiss's Theory of Fibroosseous Fixation
Weiss' theory stated that there is a fibro-osseous ligament formed between the implant and the bone and this ligament can be considered as equivalent to the periodontal ligament found in the gomphosis. He defended the presence of collagen fibers at the bone-implant interface. He interpreted it as the peri-implantal ligament with an osteogenic effect and advocate the early loading of the implant.
He believed that the collagen fibers invest the implant originating at the trabaculae of cancellous bone on one side, weaving around the implant, and reinserting into a trabaculae on the other side. When functional forces are exerted on the implant, deformation on the aspect of the implant alveolus closest to the implant surface exhibits compression which creates a negative charge, while tension at the outer aspect of the deformed trabeculae creates a positive charge there. The difference between the inner aspect and the outer aspect (tension) results in a bioelectric current (a piezoelectric effect) which induces a differentiation of the pleuripotential cells in the vicinity into components associated with bone maintenance around the implant