Management of the Posterior Maxilla
in the Compromised Patient:
Historical, Current, and Future Perspectives
CONTINUED (Page 3)
Thomas J. Balshi & Glenn J. Wolfinger
Periodontology 2000, Vol 33, 2003, 67-81.
Hard-Tissue Grafting in Conjunction with Standard Implants
When standard implant placement is contraindicated because of inadequate bony volume, one approach historically has been to augment the ridge. Breine and Brånemark first described the use of onlay composite bone grafts for reconstruction of compromised severely atrophic ridges in 198019. Although the original technique has evolved considerably since then, unpredictable resorption of the graft material has been a continuing problem20. Verhoeven et al, assessing various studies of onlay grafts, sandwich osteotomies, and onlay grafts plus hydroxyapatite augmentation, found that in the first year after bone grafting, resorption is significant and may continue for up to three years21.
Even when successful, grafting of the ridge may reduce the posterior interocclusal space so significantly as to cause prosthetic restorative problems22. Another approach, therefore, has been to augment the floor of the sinus. Introduced by Dr. Hilt Tatum in 197523, the sinus lift graft has gradually gained proponents over the years, and a 1996 consensus conference on sinus grafts organized by the Academy of Osseointegration found that sinus grafting should be considered a highly predictable and effective therapeutic modality24.
Today two basic sinus grafting strategies exist. In the first, elevation of the sinus and placement of the implants occur simultaneously. This approach offers the advantage of requiring fewer surgeries, while at the same time allowing for a shorter treatment time and reduced expense. However, at least 5mm of bone must be present in order to ensure rigid fixation of the implant at the time of placement25 (Figure 3).
When atrophy of the antral floor is more advanced, the alternative is to stage the surgeries, placing the implants six to ten months after the initial bone graft. Allowing additional time for the implants to heal in the grafted bone, the overall procedure may require a time commitment of close to two years, a prospect that is unattractive to many patients.
Furthermore, all grafting may result in complications, including infection and loss of grafted bone. As a result, placement of implants in more distant support sites in the maxilla has emerged as another potentially attractive alternative.