A Brief History

Written by Gavin Carmichael FOTA MIMPT, Principle Technologist/Laboratory Manager, East Lancashire Hospitals NHS Trust.

"I invented, designed and developed the system following a request from Philip Banks (one of our Consultant Orthodontists) for a simple method of re-activating the Twin Block appliance, without resorting either to mixing and adding acrylic in the clinic, or to sending the appliance back to the laboratory for this process.

"Clinical addition of acrylic requires the mixing and application of the material in the clinical environment. This material should only be mixed and applied using downflow fume extraction system, as it generates a heavy, flammable vapour that can be irritant. It also requires trimming and polishing before refitting, both of which create a dust hazard. Laboratory re-activation usually requires a new working bite to be taken, and means that the patient either has to wait for approximately one hour, assuming there is a laboratory on site, or, if not, come back for a second appointment. Both of these methods are time consuming, and hence expensive.

"The idea for the technique was first thought out in 1994, and, after identifying suitable materials and a method of incorporating it, the first appliances to use it were fitted in 1995. With the experience gained with these, I gradually refined and developed the system over the following two years, with the current design dating back to 1997. Since then, we have fitted around 300 twin block appliances using this system. After a long search for a commercial manufacturer, the product was licensed to Ortho-Care (UK) Ltd for manufacture and sale in 2001.

"The use of the system has generated considerable financial savings for our Hospital Trust, by reducing clinical time at review stages, reducing laboratory workload, and avoiding the need for second appointments."