Augmentation of sinus floor with mandibular bore block and simultaneous: a 6-year clinical investigation

Aim of the study

To evaluate clinically a surgical technique designed to lift the sinus floor and, at the same time, to enhance primary stabilisation of extemporaneous implants in ridges of less than 5 mm in height.

Materials and methods

467 implants were placed immediately after 216 sinus lifts using monobloc grafts (69 retromolar and 147 symphyseal) in 216 patients. At the same time, trials were undertaken with and without the use of Gore-Tex^® membrane in conjunction with maxillary bone particles, mandibular cortical bone or HA, collagen sponge or fibrin.

Results

The author reports 28 implant failures (6 %), of which 19 (4,1 %) occurred after 1-6 months in function and 9 (1,9 %) in which there was progressive loss of bone in excess of 3 mm. Of the failed implants, 14 (50 %) were associated with mucosal perforation at the time of surgery. The most successful reconstructions of the lateral wall of the sinus (after 9 months) were when the spaces around the monobloc were filled with fragments of mandibular cortical bone, with or without membrane or fibrin.

Conclusion

This technique is a good alternative to conventional two-stage treatment (sinus lift followed by implant placement). The mandibular symphysis is a site well suited to providing the quantity and quality of bone for the procedure (compared with iliac crestal bone). However, a larger long term clinical study would appear to be needed.

Commentary

This technique requires a good surgical technique, especially whilst drilling the graft for the implants. The author does not provide an explanation for the correlation between implant failure and the perforation of the mucosa during surgery.