Trauma also causes bone destruction. When an implant is inserted into the bone, various soft and hard tissues are affected. The mucosa, submucosa and periosteum are cut and many of the blood vessels and nerve endings are involved. The bur then cuts through the circumferential bone lamellae, interstitial bone lamellae and Haversian system bone lamellae crushing many osteoblasts and osteocytes. Many anastamosing processes of the bone cells are severed thus stopping the food and oxygen supply to the osteocytes as well as allowing for the exit of waste products.

Often the bur may cut directly through some of the Volkmanns canals which carry the blood supply from the innermost surface of the periosteum directly to the central axial canals of a Haversian system or group of osteons.

The very nature of bone itself is quite different from most of the tissue throughout the rest of the body. For example, osteocytes, unlike most other body cells cannot regenerate by mitotic division. They die and must be removed from the calcified matrices only to be replaced by new vital cells and new Haversian systems.

The blood system often steals the calcium from the alveolar bone to maintain the calcium blood balance of the body.

So the true histogenesis of bone shows it to be in a constant state of flux. Resorption and deposition are being carried on simultaneously in various areas of the hard structures.

With all this physiological destruction, resorption and appositional bone growth, the insults given to the bone during the implant insertions further cause it to resorb. If the implant is not designed correctly and if the implant is not placed into the bone correctly and buried deep enough or if the periosteum and soft tissues are mutilated during the surgical phase, further trauma arises, rapidly loosening the implant, which in turn prematurely invites the epithelial tissue to invaginate far beyond the neck of the implant and prevents bone regeneration close to the implant during its anabolic state of metabolism.

When earlier types of screw and pin implants were used, they had to be immediately stabilized with temporary splints or prefabricated fixed prostheses. If they were left free standing, often the normal movements of the tongue, cheeks and lips would tend to further loosen these implants during the catabolic stage of bone metabolism.

The blade implants, due to their unique designs, can greatly tolerate the lateral movements during the catabolic stages of bone metabolism without any need for immediate stabilization providing the implant is correctly inserted into the bone.

Only when an implant is properly designed with large openings

xvii