[The CPBC types used for clinical choice and observation on their microstructure]

According to the primary properties of calcium phosphate bone cement (CPBCs), we have chosen certain types of them for use in cranioplasty and have observed the microstructure of their set bodies by means of SEM. Five kinds of CPBCs powder have been prepared, including: octacalcium phosphate precipitated hydroxyapatite (OCP-PHA) type, octacalcium phosphate hydroxyapatite (OCP-HA) type, octacalcium phosphate (OCP) type, calcium deficient hydroxyapatite (CDHA) type and hydroxyapatite (HA) type. The mixing liquids were deionized water and 0.25 M Na2HPO4/NaH2PO4 buffer solution. The setting time was measured by Gillmore method. The compressive strengths were measured using the TS-14 automatically measured instrument-II of single granule's compressive strength. The CPBC types used for clinical cranioplasty were defined according to Ginebra's Criteria of the CPBCs, and the ultrastructure of the set-bodies of the defined CPBC type was observed by SEM before and after its immersion in Ringer's Solution.

Two out of five CPBCs, OCP-PHA-CPBC and CDHA-CPBC were selected for clinical cranioplasty. Before and after they were immersed in Ringer's Sol., the SEM found their set-bodies to be structurally porous and to dissolve with the increase of immension time. These data indicate that OCP-PHA-CPBC and CDHA-CPBC are sufficient for the reconstruction of non-stress-bearing bone, and the porous structure of their set-bodies is advantageous to fibroplasty or fibrovasculization in their set bodies.