2. The location of the crest -in relation to defined reference points at the adjacent teeth- (i) next to adjacent teeth (mm) , (ii) at the center of each extraction socket (mm and mm2 ) and (iii) at the position of the "inter-implant/tooth papillae"(mm) In the CBCT scans measurements will be made at (i) the center of each extraction socket, (ii) between the sockets ("inter-dental septum") (iii) at the septum next to adjacent teeth Intraoral radiographs The changes in the crestal bone levels will be assessed and by measuring the distance (MBL) from a defined reference point on the implant (adjacent tooth surface) to the most coronal bone-to implant contact on the mesial and distal aspect of the implant/tooth. In the radiographs the MBL distance will be recorded to the nearest 0.1 mm using a magnifying (X7) lens.