Histomorphometric evaluation of critical defects filled by β‐ tricalcium phosphate in rats calvary

Abstract

Background : In the face of large bone losses or large areas of resorption, procedures for bone grafts are necessary to reestablish the appropriate volume and alveolar contour, in order to provide implant-supported rehabilitation. Tissue engineering has been working to find a biomaterial capable of resembling the properties of autogenous bone. Aim/Hypothesis : This study evaluated the histological and histomorphometric biocompatibility of βtricalcium phosphate (Cerasorb ® M) deployed in critical bone defects made in the calvaria of Wistar. Materials and Methods : Twenty male adults rats (mean weight of 300 g) were select, in which bone defects were created in the center of the skull. Full-thickness bone defects were created with a 7.0 mm trephine. The cavities of the control group were filled with blood clot and received the membrane of cortical bovine bone. In the experimental group, cavities were filled with β-TCP and then inserted the same membrane used in the control group. The animals were euthanized after 15 and 45 days postoperatively. The histological sections were stained with Hematoxylin-Eosin. Histomorphometric evaluation was performed using the Merz grid, quantifying the presence of newly formed bone and the qualitative and descriptive reviews of the presence of inflammatory cells, the bone formation and resorption of biomaterials in both groups were performed. Data were described using frequencies and percentages. The Fisher exact test in order to cross the variables using as significance level of P < 0.05 was used. Results : Bone formation was present and was proved by histometric analysis where at 15 days, 35.3% presented the newly formed bone in the control and 43.7% in the experimental group and the group at 45 days 45.8% in the control group and 65.2% in the experimental group. At 15 days, between the particles, immature granulation tissue was present in all specimens of the control group (100%) and in three specimens Cerasorb ® M group (60%) with no significant difference. However, at 45 days, the same phenomeNO was present only in the control group, in all specimens (100%) with significant differences across the experimental group (P = 0.004). Mature granulation tissue at 15 days, it is showed only in Cerasorb ® M group in two specimens (40%). However, the 45-day period, this phenomeNO was observed in both groups with 100%. The histometric results were clear in showing that the Cerasorb ® M served as osteoconductive and bone formation was more effective after degradation or phagocytosis of particles. Conclusions and Clinical Implications : It was observed that in later times, the bone defect was filled in all specimens characterized by connective tissue at 15 days by immature granulation tissue and at 45 days, by immature and mature granulation tissue. It was found that the β-TCP is a biocompatible and osteoconductive material.