Upper back teeth sit directly under the maxillary sinus, an air-filled space inside the cheekbone. Once those teeth are gone, the bone beneath the sinus is often too thin to hold an implant. A sinus lift raises the sinus membrane and packs bone into the space that opens up underneath it.1
One review pooled studies that used the lateral window approach in sinuses with 6 mm or less of residual bone and followed patients for at least five years. Implants placed in an augmented sinus were lost at an overall rate of 0.43% a year, with a 95% confidence interval of 0.37% to 0.49%. A meta-regression on the same data tested whether the patient had lost every tooth or only some, when the implant was placed relative to the graft, and whether the graft was the patient's own bone or a substitute. None of the three showed a statistically significant difference in the rate. The 0.43% figure is the overall weighted estimate for the pooled population; it does not mean each of those groups shared that same rate.1
Why the upper back jaw runs out of bone
The molars and premolars at the back of the upper jaw sit right beneath the maxillary sinus, a hollow, air-filled chamber built into the cheekbone. Pull a tooth from that area and two things happen at once. The ridge that used to anchor its root starts to shrink from below, and the floor of the sinus itself can drift lower from above, a shift dentistry calls pneumatization.1
Both changes work against the patient: bone height drops while the sinus expands downward into the space left behind. Given enough time, too little bone remains between the mouth and the sinus lining to hold a standard implant securely unless that bone is rebuilt first.
Surgeons can reach that space through more than one route.1 Which route to use is a separate question with its own evidence.
What the long-term data shows
A review of long-term outcomes after sinus floor augmentation, restricted to the lateral window approach in sinuses with 6 mm or less of residual bone and at least five years of follow-up, put the overall rate of implant loss at 0.43% a year, with a 95% confidence interval running from 0.37% to 0.49%.1 That figure applies to that approach and that patient group.
A meta-regression on the same pooled data tested three variables for a link to a different loss rate: whether the patient had lost every tooth or only some, the timing of implant placement relative to the graft, and the graft material (the patient's own bone or a bone substitute). None of the three showed a statistically significant difference.1
A result that falls short of statistical significance does not show that each of those groups had the 0.43% rate. That figure is the overall weighted estimate for the pooled population the review studied; it does not mean every subgroup had that same rate.
What it adds to the treatment
A sinus lift is an extra procedure layered onto implant treatment, not a substitute for any of its usual stages. The graft still has to mature into bone the implant can rely on, and that adds a waiting period on top of whatever healing time the implant itself already needs. Depending on how much bone height remains at the outset, the surgeon may place the implant the same day as the graft or wait until the graft has settled, but the graft has to heal either way.1
Two other approaches avoid the sinus lift altogether. Short implants, generally under 10 mm, need less vertical bone and can sometimes be placed without any graft at all. The Sáenz-Ravello review cited here studied the lower jaw, not the sinus area of the upper jaw, so short implants are discussed on their own page rather than compared here.2
Zygomatic implants take the more drastic route: they anchor in the cheekbone instead of a grafted upper jaw, so no sinus procedure is needed. Over an average follow-up of 75.4 months, these implants survived at 96.2% overall. In the reviewed studies, implants loaded the same day survived at 98.1% against 95% for those loaded later; these were observational study groups, not a randomized comparison of loading timing. Their trade-off is a complication tied to where they sit: sinus inflammation was reported in 14.2% of cases over five years.3
Questions patients ask
Does it matter whether the implant is placed with the graft or after it heals?
Not according to this review. In its dataset (lateral window approach, 6 mm or less of residual bone, at least five years of follow-up), a meta-regression found no statistically significant difference in implant loss between placing the fixture the same day as the sinus graft and waiting until the graft had matured.1
Does the type of bone graft change how long the implant lasts?
Not according to this review's meta-regression. In the same dataset (lateral window approach, 6 mm or less of residual bone, at least five years of follow-up), it found no statistically significant difference in loss rate between the patient's own bone and a bone substitute. The 0.43% a year figure is the overall weighted estimate for that pooled group, and it does not mean each graft type shared that same rate.1
References
- Raghoebar GM, Onclin P, Boven GC, Vissink A, Meijer HJA. Long-term effectiveness of maxillary sinus floor augmentation: A systematic review and meta-analysis. Journal of Clinical Periodontology. 2019;46(Suppl 21):307–318. doi:10.1111/jcpe.13055
- Sáenz-Ravello G, et al. Short implants compared to regular dental implants after bone augmentation in the atrophic posterior mandible: umbrella review and meta-analysis of success outcomes. International Journal of Implant Dentistry. 2023;9(1):18. doi:10.1186/s40729-023-00476-0
- Brennand Roper M, et al. Long-term treatment outcomes with zygomatic implants: a systematic review and meta-analysis. International Journal of Implant Dentistry. 2023;9(1):21. doi:10.1186/s40729-023-00479-x
This page describes published clinical practice. It is not a treatment plan, and it does not replace an examination.