Comparative Analysis of Blood Clot, Plasma Rich in Growth Factors and Platelet-Rich Fibrin Resistance to Bacteria-Induced Fibrinolysis

Alveolar osteitis (AO) is a common, painful postoperative complication after tooth extraction. Fibrinolytic activity in the extraction socket is one etiological factor. Platelet concentrates are used to prevent and treat AO. The aim of this study was to find out whether the positive effect of platelet concentrates can be related to resistance to bacteria-induced fibrinolysis. Blood from 45 human volunteers was used to prepare four media: blood clot medium as control group; PRF and PRGF first fraction (PRGF I) and PRGF second fraction (PRGF II) as study groups. Additionally, collected blood was used for blood plasma preparation on which evaluation of initial value of d-dimer concentration was performed. A solution of five different microbes (Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumonia, Bacillus cereus, and Candida albicans) was adjusted to 0.5 McFarland (1 × 10(8) CFU/mL) and then diluted to 0.25 McFarland (0.5 × 10(8) CFU/mL). The d-dimer concentration was evaluated after one and three hours of bacteria exposure. The resistance to fibrinolysis was not statistically distinguished among any media groups at any time. S. pneumoniae was statistically active in PRF after three hours. C. albicans was statistically active in PRGF II after one hour and in PRF between the first and third hour and after three hours. S. aureus and B. cereus were statistically active in PRGF II after three hours. S. pyogenes was statistically active after one hour, between the first and third hour, and after the third hour in all groups. S. pyogenes was the most active bacterium. Different blood formulations were not distinguishable based on resistance to bacteria-induced fibrinolysis. Low fibrinolytic properties of the found major microbes suggests that bacteria-induced fibrinolysis is one of the leading causes of absence of a clot in a post-extraction socket to be clinically insignificant. The initial absence of a clot or its mechanical elimination during formation or the healing period are major causes of dry socket.