Regenerative Capacity of Leukocyte-rich and Platelet-rich Fibrin in Indirect Sinus Elevation Procedure May be Dependent on Model-Specific Modification of the Centrifugation Cycle
Authors: Chandra Rampalli Viswa , Vaishnavi Varanasi , S. Chakravarthy Y. S. H. 
Published: February 2023

Context:
To compare optical density (OD) and fibrinogen content of leukocyte-rich and platelet-rich fibrin (L-PRF) generated by standard protocol (2700 rotations per minute [RPM] for 12 min) versus relative centrifugal force (RCF)-adjusted protocol across two widely used laboratory centrifuges with swing-out rotors.

Aims:
Centrifuges for PRF production generate forces in excess of 800 g. The study aimed to evaluate OD, fibrinogen content and effectiveness in bone-added osteotome sinus floor elevation (BAOSFE) of leukocyte-rich and platelet-rich fibrin (L-PRF) generated by the standard protocol (2700 RPM for 12 min) versus a RCF-adjusted protocol to generate precisely 400 g of force across two centrifuges with swing-out rotors. The outcomes were compared to a standard centrifuge configured to generate L-PRF as per the original Choukroun guidelines.

Settings and Design:
Sample size for the present study was calculated using proportional power calculation. A minimum sample size of 8 per group was needed to detect a bone height difference of 2 mm when the power of the test is 0.80 at a significance level of 0.05.

Subjects and Methods:
Based on the centrifuge and protocol used to generate L-PRF, 10 participants were assigned to each of the following groups are as follows: D group, fixed angle centrifuge (DUO Quattro®) at default setting. R-O group: Swing-out centrifuge (Remi 8C®) + standard protocol. R-A group: Remi 8C® centrifuge + RCF-adjusted protocol. C-O group: Swing-out centrifuge (Remi C854®) + standard protocol. and C-A group: Remi C854® + RCF-adjusted protocol. OD, fibrinogen content, and gain in bone fill and bone height after BAOSFE were the evaluated outcomes.

Statistical Analysis Used:
Data were analyzed using GraphPad Prism® Software version 6.0 (GraphPad Software Inc., La Jolla, USA) and SAS Software® version 9.3 versions (SAS, New Delhi, India). Data were summarized by mean ± standard deviation for continuous data and median ± inter-quartile range for the score data. The comparison between different time points was done by analysis of one-way repeated measures test, followed by post hoc test for score data. The comparison between two groups for repeated data was made by analysis of two-way repeated measures test and followed by post hoc test. Spearman's Rho correlation test was used to test the correlation between prognosis and the other variables.

Results:
L-PRF from the Remi C854® centrifuge with RCF-adjusted protocol showed OD (P = 0.152) and fibrinogen content (P = 0.232) identical to those from the DUO Quattro® centrifuge. L-PRF from Remi 8C® centrifuge with the RCF-adjusted protocol resulted in maximum postoperative bone height gain (7.01 ± 1.44 mm) and bone fill (13.50 ± 4.51 mm2) which was higher than that of the outcomes from the DUO Quattro® centrifuge (6.82 ± 2.92 mm and 12.32 ± 5.31 mm2).

Conclusions:
A reduction in RCF resulted in a less dense clot and had a positive influence on the regenerative potential of L-PRF in BAOSFE procedure.