[Pre-implantation bone graft coffering technique for posterior mandibular edentulism: between onlay grafting and regeneration].

Background: Pre-implant placement posterior mandibular bone grafts remain a challenge for maxillofacial surgeons. We present a coffering technique we prefer using in this localization.

Surgical Procedure: This original technique involves creating a sagittal mandibular groove in which a graft harvested from the retromolar region is wedged vertically, after being sharpened in a bone mill. Reconstruction of the alveolar region itself is achieved by filling up the space between this vestibular coffer and the residual alveolar ridge with particulate bone graft from the bone mill.

Results: A hundred patients were operated with this technique by the same team from 2005 to 2010. The treatment failed for four patients at 3 post-operative months. No alteration of inferior alveolar nerve was observed.

Discussion: This coffering technique seems to be fully adequate in case of a posterior mandibular atrophy with a narrow ridge and sufficient bone height. This technique has several assets. Guided bone regeneration is associated with the use of exclusively autologous bone grafts. It may be performed under local anesthesia. The donor site is close, and the regenerated bone is of good quality. Implant placement must be achieved from 4 to 6 months after graft surgery. The drawbacks of the technique are related to donor site possibilities, and to the alveolar ridge height. Morbidity is low.