A head-to-head comparison of the degradation rate of resorbable bioceramics.

Resorbable bioceramics offer advantages in healing bone defects due to their degradation capability. Degradation rates differ significantly from one bioceramic to another; nevertheless, the degradation rate should match the growth rate of new bone. In the present study, a head-to-head comparison of the degradation rate of calcium sulfate and tricalcium phosphate is conducted. First, the degradation behaviors of calcium sulfate and tricalcium phosphate are evaluated separately. The comparison indicates that the degradation rate of calcium sulfate is one order of magnitude faster than that of tricalcium phosphate. Along with a fast degradation rate, the formation of calcium phosphate on the surface of calcium sulfate pellets is also faster. A core-shell roll composed of a calcium sulfate core and a tricalcium phosphate shell is also prepared. After soaking the core-shell roll in phosphate buffered saline solution for 24 h, calcium phosphate precipitates form only on the surface of core, the part containing calcium sulfate anhydrite.

Manipulation of the degradation behavior of calcium sulfate by the addition of bioglass.

A bioactive calcium sulfate/glass composite was prepared using a sintering technique, and Ca-P-Si glass particles were prepared by spray pyrolysis. The glass exhibited bioactivity in terms of its ability to form apatite in a simulated body fluid. The glass was transformed into two crystallized phases, i.e., calcium phosphate and calcium silicate, respectively, during the heating stage. The presence of the crystallized phases retarded the densification of calcium sulfate. A high sintering temperature of 1200 °C was needed to prepare the composite. The increased addition of glass enhanced the strength and decreases the degradation rate of calcium sulfate. The new composite is not only degradable but also bioactive.