The latter (PRF membrane) is fixed in place by applying setting acrylic as an immediate provisional (Fig.6 P) over the wound, around the abutment (A) and locking into the undercut of the neighboring tooth/implant crown.  More acrylic is added for better seal later.

Repair of Dual Defects Last Next Xin Wei, DDS, PhD, MS 1st edition 02/08/2019, last revision 03/03/2019