large periapical lesion diagnosed over 11 months ago, cbct scan taken showing no exposure into sinus. Post exo, exposure into sinus membrane, membrane perforation, buccal bone loss about 1.5mm diameter at apex of root. Time taken to clean out socket, placed collagen membrane at apex of socket and against buccal dehiscence, short of sinus floor, packed allograft, bone not displaced into sinus, some pushback, implant placed with excellent stabiltiy, additional bone placed in socket, healing abutment placed.