The sandwich technique for bone augmentation of the atrophic mandible was first described by Schettler and Holtermann, with promising results. Since then, variations in this surgical procedure have been proposed by several investigators [4,5,6,7,8,9,10].

All these authors have proposed the same approach about the flap: paracrestal incision. In order to preserve the blood supply, it is of fundamental importance that the least number possible of the vessels of the soft tissue be damaged. Based on this concept, we believe that changing the flap design can obtain the improvement of the healing of the wound. The sandwich osteotomy with the tunnel technique meets these requests. This is because the incisions were only two and vertical in the buccal side. Another advantage, especially with respect to implants, is that vascularisation is maintained in the bone ridge throughout augmentation intervention; thus, the interface at the implant shoulder in terms of hard-to-soft tissue to implant interface is kept as true to the original as possible.

This technique should be applied in patients with at least 5 mm of minimal crestal amount of bone above the nerve to perform the sandwich osteotomy successfully.

We prefer to obtain not more than 5 mm of the vertical movement for the sandwich graft. Efforts to displace the segment greater than 5 mm not only risk the potential for vascular embarrassment by detaching periosteal blood supply but also can excessively rotate the segment palatally, compromising aesthetic gingival projection.

We observed no signs of impaired sensibility after the sandwich osteotomy technique. Jensen found transient paraesthesia in all patients, lasting up to 6 weeks [7].