Update in clinical procedures

The speaker recommended leucocyte-platelet rich fibrin (L-PRF) when treating defective sockets with buccal bone loss after tooth extraction. The L-PRF may be used in two protocols: ridge preservation or horizontal bone augmentation with L-PRF bone blocks (fig 7–8).

L-PRF preparation is subject to the following strict (but simple) protocol. Blood is centrifuged for 12 minutes in 8–16 tubes with silica coating, without any additives. If the patient is receiving anticoagulant treatment, their blood should be centrifuged longer. Once the tube is filled, centrifugation must begin no more than one minute after blood extraction, otherwise sub-optimal membranes will be formed. The centrifuge should be initially set up with two tubes; more tubes are then added, always two at a time in order to keep the centrifuge balanced.

Ridge preservation with L-PRF

The technique is performed with L-PRF alone, which acts as a scaffold. After extracting the tooth and removing the granulation tissue, at least three or four L-PRF membranes (or ‘plugs’) are inserted into the socket and condensed. The speaker then explained that the socket must be sealed by one or two more L-PRF membranes placed around the entrance to the socket in an envelope between the periosteum and the bone (by tunnelling the mucoperiosteum).

No post-surgical corticosteroids or antibiotics are needed, since the graft is 100% autogenous and rich in leucocytes. The speaker described some cases involving successful buccal bone plate regeneration three months after L-PRF ridge preservation.

The technique is well-documented, and it has been shown to result in lower levels of post-extraction alveolar bone resorption. Further, enhanced healing has also been shown after extraction of the third molar, with less reported pain, faster soft tissue healing and better bone quality (Temmerman et al., 2016; Castro et al., 2017a; Castro et al., 2017b).

Horizontal augmentation with L-PRF bone-block

In cases with major bony defects, the recommended approach is to use the L-PRF bone-block technique. For this, the graft should be a combination of L-PRF membranes divided into small pieces and mixed with bone substitute in a 1:1 ratio. Liquid fibrinogen, obtained with the same centrifugation method but with plastic coated tubes and three minutes of centrifugation, is added to this mixture to obtain a ‘strong’ block. The fibrin bone block obtained in this way will have appropriate mechanical qualities for bone regeneration. The block is covered with a collagen membrane which is further covered by L-PRF membranes; the latter of which is to improve the soft tissue healing above. Both membranes should be pinned to improve the stability of the graft (fig 9). This technique has been reported to achieve a mean horizontal ridge augmentation of 4.5mm, and a mean resorption rate during the healing phase of 16% (Cortellini et al., 2018).