Fibre-reinforced polymer composites for dental bridges

18-Dec-06

Fibre-reinforced composites, widely used in the aerospace and automotive industries, are now gaining in applications in dentistry and medical field to tailor performance to exacting requirements. Karbhari and Howard Strassler, a professor and director of Operative Dentistry at the University of Maryland Dental School, report the results of detailed engineering tests on dental composites containing glass and polyethylene fibres. Many reinforcing fibres add strength and toughness to dental composites, but can accelerate damage to existing teeth if they are improperly aligned. It has been found that the toughness of fibre-reinforced dental materials depends on the type and orientation of the fibre used. The three products tested were a 3 mm wide ribbon of unidirectional glass fibres, a 3 mm wide ribbon of polyethylene fibres woven in a figure-8 stop-stitch leno-weave, and a 4 mm wide ribbon of polyethylene fibres woven in a biaxial braid. The resistance to breakage and various measures of toughness of the three preparations were compared to the dental composite alone. All three fibre fabrics dramatically increased the durability and strength of the dental composite, but the polyethylene fibres braided in a biaxial ribbon performed best. Braided polyethylene fibres performed the best, boosting toughness by up to 433% compared to the composite alone.