Resorbable implant for orbital defects.

Tricalcium phosphate ceramic, a synthetic bone substitute, was inserted into defects created in the inferior orbital rims of 18 rabbits. The animals were killed after three, eight, 24, and 40 weeks. Early sections demonstrated encapsulation with fibrous ingrowth. After eight weeks, osteoid formation was evident with partial resorption of the porous mineral implant. After 24 and 40 weeks, there was progressive replacement of tricalcium phosphate ceramic with trabecular bone, without signs of infection, migration, or rejection.