Study on powdered eggshell as new bone substitute for use in craniofacial surgery

ABSTRACT

The first successful bone transplantation carried out in 1688 by Van Meek'ren, a Dutch surgeon. The ideal bone substitute should be biocompatible, osteoinductive or at least osteoconductive, available in unlimited quantity, low cost and have satisfactory mechanical properties. To accomplish these goals, autografts are still preferred material. However, bone harvesting procedures have been focused to solve the following problems; necessity of a second surgical site, morbidity and potential deformity of the donor site, an increased operative time, donor availability limitations, and resorption of autogenic bone grafts.Ten adult white New Zealand rabbits, three, 10 mm in diameter, full layer skull defects were made in the frontoparietal bone. Two bone defects were filled with hydroxyapatite and powdered eggshell, the other defect was not filled(control). All animals were sacrified at 10 weeks, the specimens were examined macroscopically to test for graft mobility. The graft with surrounding bone was then harvested and studied by histology. The results were as follows 1. Control Bone regeneration occurred nearly complete. 2. Hydroxyapatite Macroscopically - No encapsulation. Despite a gross delineation between implant and bone, imlant was firmly united to bone. Histology - Bony trabeculae surrounded by proliferated connective tissue are observed in the defect site and implant. Osteoblastic rimming is noted along the bone fragments 3. Powdered eggshellMacroscopically - Grafted site was encapsulated by proliferated connective tissue and palpable softer than the surrounding bone. Histology - The presence of eggshell particles encapsulated by fibrous connective tissue. Partial bone regeneration from the defect margin was noticed, but the bone healing was never complete. In conclusion, the use of safe and inexpensive material is recommended for filling limited bone defects in non-weight bearing areas. The use of powdered eggshell for bone substitute may also be considered, after further studies, to access its long term stability, porosity and biocompatibility.