The results of this study showed that 6-mm-long implants supporting single crowns loaded within 7 weeks from installation lose a small amount of marginal bone during 5 years of functional loading, similar to that of 10-mm-long implants. However, a higher degree of implant loss was recorded at the short implants, probably due to the fracturing of the surrounding bone.

Osseointegration (new bone-to-implant contact) developed at various rates for cortical and trabecular compartments, respectively. In the trabecular region, mesenchymal cells were identified, subsequently developing into new bone in contact with the implant surface. In the cortical compartment, however, resorptive processes were observed throughout all periods of healing. The proportion of newly formed bone percentage was lower compared with that of the trabecular area. Old bone was still present after 1 month of healing in both compartments. Bone debris and small bone particles appeared to be involved in initial bone formation.

Autologous bone blocks used to augment the alveolar bony crest horizontally allowed the complete osseointegration of implants installed after 3 months of healing. However, similar blocks of DBBM did not promote osseointegration, although the installed implants were stable owing to the osseointegration in the sites of the parent bone.

Applying either autologous bone or deproteinized bovine bone mineral to dehiscences at implants installed immediately into extraction sockets resulted in high degree of regeneration of the defects with satisfactory BIC on the denuded implant surface.

New bone was found forming from the pristine bony walls of the sinus and extending toward the most peripheral regions in both sites. While DBBM particles yielded osteoconductivity and were able to preserve over time the space within the elevated mucosa, the collagen sponge failed the goal of maintaining the space.