Comparing effects of ostrich eggshell and demineralized bone matrix on critical sized cranial bone defects

For the treatment of the cranial bone defects which are over the critical size, autogenic and/or allogenic bone grafts and alloplastic materials have been used for a long time. There are many synthetic materials for the treatment of bone defects, which have their own advantages and disadvantages. In this study; we aimed to compare the efficacy of ostrich eggshell, which is cheap and easily available, and demineralized bone matrix in healing of the critical sized cranial bone defects and to investigate the potential of ostrich eggshell in craniomaxillofacial procedures.Forty, male Wistar rats were included in the study. Subjects were separated into four groups, each group containing 10 rats. A full thickness circular bone defect, 7 mm in diameter, was created in the frontal bone of each rat. Group I (n=10) was operative control group, in Group II demineralized bone matrix, in Group III ostrich eggshell implant, in Group IV eggshell powder was applied into the defects. At the end of the 24th week, all rats were sacrificed. Computed tomographic analysis was performed to evaluate the healing of the bone defects, for bone density and ostrich eggshell implant area measurements, for volume and density measurements. New bone formation, infection, resorbtion and tissue reactions were evaluated by an experienced histologist.Macroscopic examination revealed that ostrich eggshell implants were slightly resorbed, in the other hand they were integrated with surrounding bone, stable and supplied a good cranial completeness. In the other hand, ostrich eggshell powder particles were totally resorbed at 6th month.Radiologic examination revealed that there were no statistically significant difference between group I, II and IV, for the decrease in the defect area, for the bone density at 12th week and for the percentage of healing area (p>0.05). Group I and II?s bone density at 24th week was statisticaly significantly greater than group IV?s bone density at 24th week. Ostrich eggshell powder particles and demineralized bone matrix were not observed at computed tomographic scans taken at 6th month. There were statistically significant decrease in the ostrich eggshell implant area and volumetric values, but there was no statistically significant difference between 0th and 6th month density values. Histological examination revealed that there was not significant difference between control and ostrich eggshell groups for the new bone formation. In the other hand, in demineralized bone matrix group a greater amount of new bone formation was observed.In conclusion, ostrich eggshells did not seem to be an osteoproductive material. But there are some important advantages of the ostrich eggshell as an implant. Ostrich eggshell has a strong structure and a low resorbtion rate, it did not cause a tissue reaction or infection. The material could be shaped very easily and it is very cheap compared to many other materials used in craniomaxillofacial reconstructions. Ostrich eggshell could be a good alternative graft material for orbital floor fractures, cranial and maxillofacial augmentation procedures. Further experimental and/or clinical studies are required to find out the potential of the ostrich eggshell in craniomaxillofacial reconstructions.