Use of Platelet-Rich Plasma and Platelet-Rich Fibrin in Dentistry and Oral Surgery: Introduction and Review of the Literature

Question 1

What is platelet rich plasma?

Answer 1

Platelet-rich plasma is a concentrate of PRP protein obtained from whole blood and centrifuged to remove the red blood cells

Question 2

What is platelet rich fibrin ?

Answer 2

Platelet-rich fibrin is a second-generation platelet-rich concentrate where autologous platelets and leukocytes are present in a complex fibrin matrix

Question 3

What is the advantage of PRF over PRP?

Answer 3

Simple preparation, minimal expense, and the absence of added anticoagulant and formation of an homogenous 3-dimensional organization that has a long-term effect on tissue healing by slowly releasing cytokines

Question 4

What is the normal lifespan of an inactivated platelet?

Answer 4

7-10 d

Question 5

What are two important platelet cytokines?

Answer 5

Transforming growth factor b (TGF-b), which affects synthesis of collagen and fibronectin through osteoblasts or fibroblasts, and platelet-derived growth factors (PDGFs) that are essential regulators for migration, proliferation, and sur- vival of mesenchymal cells.

Question 6

Through what mechanism can allergic reactions and coagulopathies occur when PRP is used

Answer 6

Antibodies to factors V, XI, and thrombus formation can cause these reaction because bovine thrombin is used to produce a PRP gel.

Question 7

What percentage of PRP is platelets? What is the normal percentage of platelets in a clot?

Answer 7

95 % and normal percentage in a clot is 5%

Question 8

How much PRP is obtained obtained from 8 mL of whole blood using most of the reported PRP protocols

Answer 8

1ml

Question 9

By what process is PRP prepared?

Answer 9

Platelet-rich plasma is prepared by a process known as differential centri- fugation

Question 10

What is separated in the first spin?

Answer 10

The first spin (hard spin) will separate the red blood cells from the plasma that contains the platelets, white blood cells, and some clotting factors

Question 11

What is separated in the second spin?

Answer 11

The second spin (soft spin) will separate the platelet concentrate (PRP) from the platelet-poor plasma (PPP).

Question 12

How can liquid PRP be turned into a gel?

Answer 12

A weak gel can be produced by adding calcium chloride and bovine thrombin.

Question 13

When should freshly prepared PRP be used?

Answer 13

Freshly prepared PRP should be used within 4 hours of isolation for optimum results

Question 14

How quickly are growth factors secreted and for how long?

Answer 14

The release of growth factors begins within 10 minutes after preparation, and almost 95% of the growth factors are secreted within the first hour

Question 15

How long does PRF secrete growth factors for

Answer 15

PRF has a sustained release of growth factors for 1 to 4 weeks.

Question 16

what is the difference between a normal clot and PRF?

Answer 16

In PRF use physiological healing is accelerated, because the PRF is better organized, it is able to more efficiently obtain stem cell harnessing and healing.
It is more homogenous, stable, and easier to handle and place locally

Question 17

How can the PRF be used as a reservable membrane?

Answer 17

Platelet-rich fibrin can be used as a resorbable mem- brane for guided tissue regeneration,24 thus preventing migra- tion of nondesirable cells (epithelial cells) into the bony defect, providing a space for influx of osteogenic and angiogenic cells, and allowing mineralization of the underlying blood clot.

Question 18

What are the known cytokines and growth factors in PRF.

Answer 18

Interleukin 1b (IL-b), IL-4, tumor necrosis factor a, PDGF a and b, TGF-b1, insulin-like growth factor 1, and vascular endothelial growth factor (VEGF). Transforming growth factor b1, PDGF-AB, and VEGF

Question 19

What is fibrin

Answer 19

Fibrin is an activated form of the molecule fibrinogen

Question 20

What are the platelets most important elements in healing and repair?

Answer 20

Leukocytes and growth factors, which participate in differentiation, proliferation, migration, and cell metabolism.34

Question 21

Where in the fibrin clot are the platelets found?

Answer 21

Platelets are accumulated in the lower part of the fibrin clot, mostly at the junction between the red corpuscles and the PRF clot itself

Question 22

What are the 4 mechanisms by which PRF influences tissue healing.

Answer 22

Angiogenesis, immune control, harnessing the circulat- ing stem cells, and wound protection by epithelial cover

Question 23

How is the PRF prepared?

Answer 23

The collected blood sample is placed in a 10-mL glass or glass-coated plastic tube and immediately centrifuged at 3000 revolutions per minute (rpm) for 10 minutes using a PC-02 table centrifuge

Question 24

What are the three layers of the PRF

Answer 24

The PRF product consists of 3 layers: cellular plasma on the top, the PRF clot in the middle, and the red corpuscles at the bottom

Question 25

Why is a glass tube required?

Answer 25

The blood starts to coagulate as soon as it comes in contact with the glass surface. In order to activate the clot polymerization, contact with a silica surface is needed. therefore, PRF can only be obtained in dry glass or glass-coated plastic tubes

Question 26

What is the most important factor in determining success?

Answer 26

The success is reported to depend entirely on the speed of blood collection and its transfer to the centrifuge

Question 27

How did the Fennis study show that PRF stimulated bone healing?

Answer 27

Vascular ingrowth into the central parts of the grafts were quantified by counting the capillaries per microscopic field.

Question 28

What did Choi demonstrate with respect to PRP concentrations and bone healing?

Answer 28

The cells exposed to PRP showed a concentration- dependent variability and proliferation with significant increase using 1% and 5% PRP concentrations. Alveolar bone cells exposed to PRP concentrations of more than 30% showed significantly less growth compared to control cultures without PRP, and cells exposed to 100% PRP displayed marked toxicity.

Question 29

What is the life expectancy of a regular PRF membrane

Answer 29

1-2 weeks

Question 30

What did Simon et al report in alveolar ridge augmentation in dogs?

Answer 30

They concluded that PRFM alone may be the best graft for ridge preservation procedures. 4 group PRFM and membrane, DFDBA and membrane, DFDBA or PRFM

Question 31

What areas have shown good results in healing with the use of PRF or PRF membranes?

Answer 31

Intrabony pockets, guided tissue regeneration, gin- gival recession, postextraction healing, and osseous regeneration.

Question 32

What did Sezgin et al show with respect to intrabony defect healing?

Answer 32

They concluded that there was a greater reduction in PD, more clinical attachment gain, and greater intrabony defect fill at sites treated with PRF and open flap debridement compared to open flap debridement alone

Question 33

How did the use of PRF help in cases of BRONJ and MRONJ?

Answer 33

BRONJ The results indicated complete resolution in 77% (at 1 month), delayed resolution in 18% (at 4 months), and 6% did not resolve at all. M RONJ showed early resolution

Question 34

What was the only benefit Canellas noted with use of PRF in extractions?

Answer 34

PRF did not offer any benefits in bone healing except as a preventive measure for alveolar osteitis.

Question 35

What 2 principles have to be followed in all periodontal surgeries using PRF membranes according to Del Corso?

Answer 35

1. At least 2 PRF layers are required in order to obtain adequate matrix volume and core material homogeneity 2. The membranes must be placed over the recession with a slight over- hang, therefore controlling the migration and early invagina- tion of the gingival epithelium

Question 36

How does the PRF membrane present epithelial down growth.

Answer 36

The function of the PRF membrane is not to create a cell-proof strong barrier but to impose a competitive barrier between the epithelium and the connective tissues