Active_comparator: khoury block graft

Bone blocks will be harvested from the retromolar area after measuring of the size required and measuring of the donor site anatomy. Piezoelectric device will be used to perform the graft osteotomy. The osteotomy lines will be connected and the graft will be mobilized using a bibeveled chisel and mallet. Sharp bony edges will be smoothened and the donor defect was packed with gelatin sponges. The bone block margins will be smoothened and separated into two thinner bone shells using titanium disk with copious saline irrigation. The blocks will be fixed into the recipient site buccally using at least two microscrews leaving a gap to be filled with bone graft. Particulate xenogenic bone graft will be mixed with the autogenous bone chips (50% Xenograft: 50% Autogenous graft) to fill the gap between the buccal bone plate and the fixed bone shells. The augmented site will be covered with a pericardium membrane.

Active_comparator: urban sausage technique

A resorbable pericardium membrane will be fixed with titanium pins on the lingual bone plate (2-3mm from the bone crest) and on the buccal bone plate allowing for packing of particulate mix of bone graft (50% Xenograft: 50% Autogenous graft). Overfilling of the graft will be respected to compensate for future resorption. The membrane will be stretched over the graft ensuring maximum immobilization of the graft.

Active_comparator: guided bone regeneration using PTFE membrane

A non-resorbable polytetrafluoroethylene (PTFE) membrane will be fixed with titanium tacks on the lingual bone plate (2-3mm from the bone crest) and on the buccal bone plate allowing for packing of particulate mix of bone graft (50% Xenograft: 50% Autogenous graft). Overfilling of the graft will be respected to compensate for future resorption.