Study On Compressive Strength Of Calcium Phosphate Bone Cement

Calcium phosphate cement (CPC) is a kind of promising materials used in dental and orthopeadic restoration. Nowadays, CPC is of special interest due to its self-setting behavior when mixed with an aqueous liquid phase. Currently, the high brittleness and low strength of calcium phosphate cement (CPC) restrict its application in many load-bearing and weak bone sites; it is important to improve the mechanical strength of CPC to expand its application.In this study,α-tricalcium phosphate (α-TCP) and tetracalcium phosphate (TTCP) were served as the solid component of the cement, and the liquid component was consist of sodium phosphate dibasic dedocahydrate (Na2HPO4·12H2O), and/or citric acid. The cement's properties as compressive strength and porosity were measured. The effects of preparing conditions, such as particle size of the solid component, liquid-to-powder ratio (L/P) and liquid composition, on compressive strength of calcium phosphate were investigated.The results show that the particle size ofα-TCP has no obvious regularity on the compressive strength of the cement. The compressive strength increases with the decreasing of setting liquid's pH value. There is a premium L/P in which the compressive strength gains its maxim. The compressive strength reached 21.69MPa at the condition of L/P=0.30mL/g and pH=5 in the sample that employs wet-method synthesizedα-TCP.However, the water-based CPC paste, together with sodium phosphate dibasic dedocahydrate and citric acid, is not highly cohesive and is vulnerable to washout until hardening occurs. This study investigated the effects of xanthan gum on wash-resistance, cement hardening behavior, and mechanical properties under acidic and basic setting liquids. Resistance to washout was evaluated by the disintegration of the cement specimen in water with agitation. The results show xanthan gum has little effects on setting time, compressive strength, and hardening product of the cement, but it can improve the cement's property of wash-resistance.