Comparison of the effect of Nano Ostrich Eggshell and Hydroxyapatite on Bone Defect Healing in Rat Calvaria

Background: Fracture healing is important in medicine; thus seeking new techniques with fewer side effects to improve the speed of the healing is prudent. Objectives: This experimental study sought to assess the effect of the nano ostrich eggshell (N-OES) and hydroxyapatite (HA) composite on bone defect healing in rat calvaria. Methods: In this study, a 7-mm bone defect was created in the calvaria of 45 male Sprague–Dawley rats. The animals were randomly divided into three groups, and the defects in each group were filled with N-OES, HA, or as a control group. The animals were euthanized and histological and serological assessments were carried out at 14, 28 and 42 days after the operation. Results: At 14 and 28 days after the operation, in the edges of the defect, there was a significant difference between the treatment and control groups (p ≤ 0.05). However, there were no statistically significant differences between N-OES and HA treatment groups (p > 0.05). At this time, in the center of the defect, there was a statistically significant difference between the N-OES group with HA and control groups (p ≤ 0.05). On day 42, no significant difference in the edges of the defect was observed between all groups. However, there was a statistically significant difference in the center of the defect between the N-OES group with HA and control groups (p ≤ 0.05). Results of the serological assessment indicated that the applied treatments increased the serum levels of alkaline phosphatase. Conclusions: The results of this study indicate the potential efficacy of nano ostrich eggshell as a bone substitute in rat calvaria defects.