Acrylic bone cement and starch: Botanical variety impact on curing parameters and degradability.

Acrylic bone cements are a conventional solution to heal bone defects. Starch is often added to the cement to improve its degradability and resorbability. The most used botanical variety is corn starch; few studies or applications deal with other varieties. This study focuses on classical formulations based on 2-hydroxyethylmethacrylate but incorporating different starches: waxy maize, corn, amylo maize, wheat, pea or potato, with or without enzyme (α-amylase). A thermocouple is used to determine the curing parameters: setting time and maximal temperature. The water uptake depends on the cement immersion time in a biological fluid and it is studied through sample mass variation analysis. The weight loss is determined after immersion (function of the time) and drying. Starch botanical variety and enzyme presence do not impact curing parameters and water uptake but strongly influence degradability. Water uptake involves advantageous swelling in situ filling the defect. This study shows that starch accessibility by the enzyme explains this impact. Grain spatial configuration, specific surface area and starch distribution in cement give a complementary explanation of the well-known influence of the ratio amylopectin/amylose. Acrylic cements incorporating starch can be classified according to their degradability.