Use of Circularly Polarized Light on the Evaluation of Injectable Platelet Rich Fibrin in the Early Formation of Woven and Lamellar Bone: A Specific Method in the Study of Osseous Tissue

Abstract

Purpose: In bone grafting, the goal is the formation of 100% vital bone. The ideal graft material is osteogenic, osteoconductive and osteoinductive and can be evaluated by histology and histomorphometric methods to calculate percentages of vital bone formation, residual graft material and connective tissue. Bone graft substitute materials currently used include allogeneic, xenogeneic and alloplastic materials. The goal of this study is a histological evaluation of the early effects of the liquid (injectable) form of Platelet Rich Fibrin (i-PRF) on the formation of woven and lamellar bone using Circularly Polarized Light (CPL). Patients and Methods: This is a retrospective cohort study of forty-two patients from 2021 to 2022 who completed bone grafting after a non-restorable endodontically treated molar tooth was extracted in preparation for future implant surgery. Each bone graft was augmented with i-PRF. To process i-PRF, Relative Centrifugation Force (RCF) was reduced from 2,700 RPM to 700 RPM (60 g). Centrifugation time was reduced from 12 minutes to 3 minutes. After an average bone graft healing time of 8 to 12 weeks, bone core samples were obtained at the time of implant surgery for histological and histomorphometric analysis. Bone cores were stained with Stevenel’s blue and van Gieson’s picrofuchsin for histologic analysis by means of brightfield and circular polarized light microscopic evaluation to evaluate the early effects of the liquid form of PRF on formation of woven and lamellar bone using allogeneic bone. Results: Forty-two bone cores were harvested at the time of implant surgery for histological and histomorphometric analysis. The liquid form of PRF resulted in greater percentages of vital bone formation (average 87.4 %) compared to the existing published literature. CPL analysis of forty-two bone core specimens showed the positive effects of i-PRF on de novo bone formation. Conclusion: The results of this study using circularly polarized light demonstrate that the liquid form of PRF (i-PRF) resulted in greater percentages of early, new vital bone formation compared to the published literature. Circularly polarized light should be considered as an adjunctive method to determine bone maturity and structure.