Injectable platelet rich fibrin (i-PRF) versus platelet rich fibrin (PRF) both mixed with beta-tri calcium phosphate in bone regeneration using metacarpal bone defect in goats: micro CT comparative study

The aim of this research is to compare the regenerative capability and the bone regeneration rates of i-PRF mixed with β-TCP vs. PRF mixed with β-TCP when used for GBR within critical size defects created in metacarpal bone in a goat model, using (micro-CT) analysis. Eighteen male Najdi strain goats with a mean body weight of 30 ± 2 kg and a mean age of 8 ± 1.5 months were selected. Under a full-sterilized environment, all animals underwent the same surgical procedure in the left metacarpal bone. Four critical size defects were created in the lateral aspect of the left metacarpal bone as following: Group I (Negative control group): The 1st proximal critical size defect was allowed to heal spontaneously. Group II (βeta-Tri-calcium phosphate - β-TCP): The 2nd following critical size defect was treated with β-TCP. Group III (β-TCP + PRF group): The 3rd following critical size defect was treated with β-TCP mixed with PRF. Group IV (β-TCP + i-PRF group): The 4th following critical size defect was treated with β-TCP mixed with i-PRF. Under general anesthesia and veterinary supervision, the four (monocortical) critical size defects were created on the left metacarpal bone using bone trephine bur with an outer diameter of 6.1 mm and inner diameter of 5.25 mm. The critical size defects were treated according to the groups mentioned above. The eighteen goats were allocated to three sacrifice time points (2, 5, and 8 weeks; n = 6 per time point). Four defects per goat were analyzed at each time point using micro-CT scan. A quantitative assessment of new bone formation (Bone Volume for Newly Formed Bone) (BV-NFB), a qualitative assessment for mineral density (Bone Mineral Density for Newly Formed Bone) (BMD-NFB), β-TCP Volume (TCPV), β-TCP Mineral Density (TCPMD), Trabecular Thickness (Tb-Th), Trabecular Separation (Th-Sp) and Trabecular Number (Th-No.) assessments were performed at the 8th week scan cycle. The mean values of BV-NFB were 39.455 mm³, 58.995 mm³, 62.665 mm³ and 80.083 mm³ by the 8th week for group I, II, III and IV respectively. Along with the mean values of BMD-NFB were 0.425 g/mm³, 0.799 g/mm³, 0.802 g/mm³ and 0.822 g/mm³ respectively. By the 8th week, the mean values of the remaining TCPV were 24.972 mm³, 22.013 mm³ and 15.319 mm3 for groups II, III and IV respectively, and the mean values of TCPMD were 0.734 g/mm³, 0.725 g/mm³ and 0.720 g/mm³ respectively. The means of NFBV, NFBMD, (Tb-Th), (Th-Sp) and (Th-No.) in β-TCP + i-PRF group were significantly higher than the other groups during the 2nd, 5th and 8th week. In our study, the combination of β-TCP particles and i-PRF can promote regenerative bone healing in comparison to β-TCP alone or β-TCP with PRF within a critical size defect in metacarpal bone of goats. The Micro-CT results revealed that a mixture of β-TCP particles and i-PRF show great difference in means of quantity (BV-NFB) and quality (BMD-NFB) within a critical size defect in metacarpal bone of goats.