Fabrication and Analysis of Round and Rectangular Photopultruded Composite Archwires and Their Clinical Use as Flexible Bonded Orthodontic Retainers

From the straw-reinforced bricks of Egypt to the structural components of advanced aircraft, the belief that a combination of different classes of materials can be combined to achieve properties greater than their individual components has been widespread. Composite materials have been used since antiquity, and applications for their uses have continued to be developed throughout the 20th century, resulting in continued research into their design and processing. In 1951, W. B. Goldsworthy patented a continuous process for making fiber- reinforced composites called pultrusion. This manufacturing process consisted of polymer-impregnated fibers that were "pulled-through" a heated die that shaped the material and cured the polymer. Although, the first application of pultrusion was in the manufacture of fiberglass fishing rods, uses were soon discovered in the hardware, aerospace, defense and medical fields. In the past decade, two patents have been issued for applications of thermal pultrusion in the field of dentistry. This pultrusion process is ideally suited for the fabrication of small profile composites and has been recommended for use in dentistry to fabricate frameworks for provisional bridges, splints, retainers, space maintainers and orthodontic archwires. Although these materials have mainly utilized thermoplastic polymers, numerous polymer matrices and reinforcement fiber combinations have been documented.