EFFECT OF REINFORCEMENTS ON PROPERTIES OF SELF-SMING CALCIUM PHOSPHATE CEMENT

Calcium phosphate cement makes a suitable material to be used for craniofacial and orthopedic repairs because of its biocompatibility, bioresorbability and quick setting properties. These materials have an advantage over polymers and metals in that they are non-toxic and lightweight. However, the low strength of calcium phosphate prohibits its use in stress bearing bone joints. This study investigates the improvements in mechanical properties of calcium phosphate cement by reinforcements. Monocalcium phosphate monohydrute (Aldrich Chemicals, Milwaukee, WI) and beta-tricalcium phosphate, synthesized by the organic steric entrapment method, were the primary components of the cement. Upon setting the cement transformed into brushite. beta-TCP and cement after setting, were analyzed by X-ray analysis, EDS. Two different types of reinforcements were used, namely, (a) chopped hydroxyapatite (HA) fibers, and (b) borosilicate glass spheres. Rod shaped particles (less than 500 mu m in length) were made by chopping the sintered HA fibers (about 115-120 mu m in diameter). Borosilicate glass spheres, prepared by glass melting methods, had diameters in the range of 25 to 70 mu m. Samples were prepared with different weight fractions of the reinforcements, and tested both in flexure and compression mode. Effects of size, shape, and weight fraction of the inclusions on the strength of the biocomposite are discussed.