Instructions for the use of L-PRF in different clinical indications

Abstract

Autologous platelet concentrates (APCs) have demonstrated clear benefits across various clinical applications, including alveolar ridge preservation, guided tissue regeneration, guided bone regeneration, sinus floor elevation (both lateral window approach and transcrestal technique), endodontic surgery, the treatment of medication-related osteonecrosis of the jaw bones, and periodontal plastic surgery. To ensure an optimal clinical outcome, clinicians must adhere strictly to the protocol to prepare the APCs and, especially follow evidence-based surgical guidelines, often simple but crucial, to minimize the likelihood of errors. The majority of clinical trials reported on second-generation APCs [the leukocyte- and platelet-rich fibrin (L-PRF) family, including its modifications (A-PRF, A-PRF+, CGF, T-PRF, H-PRF, etc.)]. These second-generation APCs offer additional benefits compared to the first-generation APCs, making them the preferred choice for the development of clinical recommendations. These recommendations have been formulated through a meticulous examination of the available clinical data and the clinical experience of the authors of this paper.

Keywords: alveolar ridge preservation; autologous platelet concentrates; flowcharts; guided bone regeneration; guided tissue regeneration; intra‐bony defects; medication‐related osteonecrosis of the jaw bones; plastic periodontal surgery; sinus floor elevation (lateral window technique, transcrestal technique).

FIGURE 1

Images of L‐PRF clot/membrane/plug. After centrifugation, the L‐PRF clots can be collected from the blood tube with tweezers, and the adhering red blood cells must be removed. Since most platelets and leukocytes are concentrated just underneath the red blood cells (in the area indicated by the dotted blue line), this step has to be performed very gently. After compression (compression box) strong L‐PRF membranes are generated (one membrane can carry a weight up to 500 g). A cylinder and piston (in the compression kit) can be used to make cylindrical L‐PRF plugs, suitable for filling extraction sockets or bone cavities. The fluid leaking out of the clots into the lower part of the box during compression is called the exudate.

FIGURE 2

L‐PRF bone‐blocks have the physical characteristics of gummy bears (candy), exhibiting intrinsic form memory.

FIGURE 3

Alveolar ridge preservation with L‐PRF for a nearly intact extraction socket. Several L‐PRF plugs are tightly packed (good condensation) throughout the entire area. The entrance to the socket is sealed with two L‐PRF membranes. Place the face portion (in orange, i.e., the area with the highest concentration of platelets and white blood cells) towards the socket. L‐PRF membranes are slid under the periosteum over the bony socket borders (in the envelope created between the periosteum and bony borders, covering 3–5 mm of bone). Suturing is completed without any attempt to close the wound; its only purpose is to keep the L‐PRF in the socket (healing by secondary intention). Small perforations can be created in the bony socket walls to improve the vascularization, and as such optimize the healing/bone formation. Figure adapted from Quirynen & Pinto (2022).

FIGURE 4

Alveolar ridge preservation with L‐PRF for a socket with bony dehiscence. The bone dehiscence is covered by a double layer of L‐PRF membranes (extending 5 mm beyond the bony borders of the dehiscence). The face portion of the inner L‐PRF membrane is facing the bone dehiscence. L‐PRF plugs are tightly packed throughout the entire area, including the bony dehiscence. The entrance to the socket is also sealed with the above‐mentioned double layer of L‐PRF membranes. Suturing is completed without any attempt to close the wound, its only purpose is to keep the L‐PRF in the socket (healing by secondary intention). Deeper sutures should not run over the bony dehiscence because it might push the L‐PRF out of the socket; sutures must be supported by bone. Small perforations can be created in the bony socket walls to improve the vascularization, and as such optimize the healing/bone formation. Figure adapted from Quirynen & Pinto (2022).

FIGURE 5

Alveolar ridge preservation using a bone substitute in combination with L‐PRF. A double layer L‐PRF membranes covers the bony dehiscence (extending 5 mm beyond the bony borders of the dehiscence). The inner L‐PRF membrane is positioned with the face portion towards the bony dehiscence. The entire space is densely packed with the L‐PRF bone‐block (a combination of a bone substitute (blue stars), liquid fibrinogen (orange), and small pieces of L‐PRF membrane). The entrance to the socket is also sealed with the above‐mentioned double layer of L‐PRF membranes. Suturing can be done without any attempt to close the wound, its only purpose is to keep the graft in the socket (healing by secondary intention), or one can opt for healing by primary intention (safer). Deeper sutures should not run over the bony dehiscence because it might push the graft out of the socket; sutures must be supported by bone. Small perforations can be created in the bony socket walls to improve the vascularization, and as such optimize the healing/bone formation. Figure adapted from Quirynen & Pinto (2022).

FIGURE 6

Final situation after a transcrestal (trans‐alveolar) approach for sinus augmentation using L‐PRF as the only grafting material. A small part of the floor of the sinus and several L‐PRF membranes separate the Schneiderian membrane from the apex of the implant. Several membranes fill the space around the implant and the exposed inner bony walls of the sinus. In total, three to five membranes are required for a single implant in order to gain 3–4 mm of bone height. Figure adapted from Quirynen & Pinto (2022).

FIGURE 7

Final situation after a lateral window approach for sinus augmentation with immediate implant placement using L‐PRF as the only grafting material. Two double‐folded L‐PRF membranes, with their face portions facing the sinus, are used to cover the Schneiderian membrane and the bony window. The entire space between the implant and bony walls, as well as the window, is filled with L‐PRF membranes. The entrance to the sinus is sealed with another L‐PRF membrane (face portion towards the sinus). Perforations in the alveolar bone (eventually trough and trough) can increase the blood supply to the sinus and as such optimize the healing/bone formation in the sinus. Figure adapted from Quirynen & Pinto (2022).

FIGURE 8

Final situation after a sinus augmentation via a lateral window approach with an L‐PRF bone‐block for a two‐stage procedure. The Schneiderian membrane (and bony window) is covered with two double‐folded L‐PRF membranes (face portion towards sinus). The entire created space in the sinus is densely packed with pieces of a L‐PRF bone‐block (a combination of bone substitute (blue stars), liquid fibrinogen (orange), and small pieces of L‐PRF membrane). The window is filled and sealed with a double‐folded L‐PRF membrane. Perforations in the alveolar bone (eventually made through and through) can increase the blood supply to the graft, and as such optimize the healing/bone formation in the sinus. Figure adapted from Quirynen & Pinto (2022).

FIGURE 9

L‐PRF bone‐block for lateral bone augmentation. The L‐PRF bone‐block is well adapted to the native bone. The small perforations in the cortical bone guarantee optimal blood supply and a strong connection between graft and native bone. The slow‐absorbing or non‐absorbable membrane (in white) and membrane tacks provide extra stability to the graft. L‐PRF membrane(s) protects the regenerate in case of a wound dehiscence. Primary closure will facilitate healing. So far it is not well understood whether and when a slow‐ or non‐absorbable membrane is required. Figure adapted from Quirynen & Pinto (2022).

FIGURE 10

Final situation after the use of L‐PRF for the regeneration of an intra‐bony defect around a tooth. The intra‐bony defect is filled with chopped L‐PRF membrane parts (preferably the face portion) and covered with L‐PRF membranes, with the face portion of the inner membrane oriented towards the bony defect. Care should be taken to ensure the membranes extend over the buccal and lingual bony borders. Primary closure should be obtained. (Several strategies have been proposed, but this protocol seems to be the most logical). Figure adapted from Quirynen & Pinto (2022).

FIGURE 11

Final situation after gingival recession coverage with CAF and L‐PRF membranes. Several (in this case 4) L‐PRF membranes are placed on the receptor bed and over the recession (with the face portion of the deepest membrane oriented towards the exposed root). These membranes are sutured to the periosteum to increase graft stability. The flap is coronally advanced over the recession(s), and sutured in the new position. Figure adapted from Quirynen & Pinto.