Coralline-sulfate bone substitutes

Filling irregular defects caused by trauma or surgery with particulate bone substitutes usually results in migration of the particles from the wound. Coralline blocks have been used successfully to replace diseased bone. Immobilizing coralline particles should be useful in repairing bone defects. Coralline particles of < 45 microns were blended with < 45 microns particles of calcium or zinc sulfate (10%, 20% or 30%). Five gram blocks (20 x 10 mm) of the mixture were pressed at 800 pounds force. Blocks of coral-calcium sulfate were heated at 1000 degrees C and coral-zinc sulfate at 500 degrees C for two hours. The heated blocks were cooled, crushed and sized to < 45 microns particles. Distilled water (200-240 microliters) was added to 210 mg of coralline or coralline-sulfates. A circular rubber mold (10 x 4 mm) was filled with the paste and allowed to harden. Hardness was tested by applying pressure to the tablets at four minute intervals. Consistency equivalent to hardened plaster of Paris was recorded as maximum hardness. Coralline alone did not harden on addition of water. Mixing sulfates with coralline immobilized the particles to maximum hardness within 60 minutes on addition of water. Variation in the amounts of sulfate added (10%-30%) to coralline did not affect the hardening characteristics of the composite.