Why The ALF Appliance? Part 4

There appears to be no connection between orthodontics and this elegant construction of metal rods and stainless steel wire but in fact, there are significant clues which we can use. This is what is known as a tensegrity structure. It consists of a single continuous wire cable and struts of aluminum. The struts do not touch each other and there are no joints or levers. The only forces are of continuous tension ( the wire cable) and interrupted compression (the struts). The structure is 20 metres in height but almost appears to defy gravity. Despite its height and fragile appearance, it has both considerable strength and flexibility.

Many years ago, orthopedic surgeon Stephen Levin was struck by these features and realised that the same construction principles could be found both in some man-made structures and in live organisms. Tensegrity is a word coined by Buckminster Fuller from tensional integrity to describe a form of architecture, the geodesic dome. Levin devised the name Biotensegrity to describe the organic examples of tensegrity which can be found throughout nature. In biological structures, the characteristics of tensegrity are especially valuable. As well as strength, flexibility, and absence of levers these structures are energy efficient. Another feature of special interest is that when a force is applied to any part of a tensegrity system, it is immediately spread through the whole system giving a considerable adaptive capacity to the organism.

The ALF appliance was designed well before the significance of biotensegrity was recognized but it has proved to be very suitable as a way of introducing appropriate forces. To grasp how this comes about we have to study the smallest organism capable of survival as an independent entity, the cell.

Gavin