There are two routes into the sinus. One opens a window in the side of the jaw. A second, the transcrestal approach, works through the hole already being drilled for the implant, which makes it the smaller of the two procedures.
In sites with 6 mm or less of residual bone, implants placed the transcrestal way survived at 96.5% (95% CI 93.2 to 98.9) over a year or more of follow-up, and sinus membrane perforation occurred in 5.4% of cases (95% CI 2.7 to 8.8). In that same 6 mm or less group, survival, perforation and marginal bone loss showed no statistically significant difference between the two routes, and the transcrestal route left patients more satisfied.1
The two routes
In the lateral approach, the surgeon cuts a small window in the outer wall of the jawbone next to the sinus and lifts the lining through it. Graft material goes in underneath, and the implant follows, either then or later. Transcrestal surgery skips the window. The surgeon works from above, through the same site being drilled for the implant, and nudges the sinus floor upward with instruments passed down that one channel.
Figures on this page come from a review of the transcrestal route in sites with 6 mm or less of residual bone below the sinus: survival of 96.5% (95% CI 93.2 to 98.9) at a year or more, and membrane perforation in 5.4% of cases (95% CI 2.7 to 8.8), both figures for that 6 mm or less group.1 A perforation is a tear in the thin lining of the sinus. It is tracked separately from implant failure because a torn membrane does not always end the case.
| Transcrestal | Lateral | |
|---|---|---|
| Access | Through the implant site itself | Through a window in the side of the jaw |
| Surgical sites | One | Two: the window and the implant site |
| Survival, 1 year+ | 96.5% (95% CI 93.2–98.9), transcrestal cohort, residual bone ≤6 mm1 | |
| Membrane perforation | 5.4% (95% CI 2.7–8.8), transcrestal cohort, residual bone ≤6 mm1 | |
| Bone height ≤6 mm | No statistically significant difference between routes in survival, perforation or marginal bone loss1 | |
| Patient satisfaction | Higher for the transcrestal route1 | |
Where the evidence is weak
This review states its own limitation plainly: the individual studies it pooled carried a high risk of bias.1 That does not overturn the 96.5% survival figure for sites with 6 mm or less of residual bone, or the finding that the difference between routes at that same bone height did not reach statistical significance. It does mean both rest on a thinner base than the confidence intervals alone suggest.
A single well-run trial could still move either number. The review's own authors concluded as much, so treat these figures as the current best estimate rather than a closed question.
Questions patients ask
Does the smaller procedure mean a lower survival rate?
Not based on this review. In sites with 6 mm or less of residual bone, implants placed through the transcrestal route survived at 96.5% (95% CI 93.2 to 98.9) a year or more after surgery, and the review found no statistically significant difference in survival compared with the lateral route at that same bone height.1
What if the sinus membrane tears during surgery?
Tears occurred in 5.4% of the transcrestal cases pooled for this review (95% CI 2.7 to 8.8), all in sites with 6 mm or less of residual bone. A perforation is the main technical complication tracked for either approach, and on its own it does not mean the implant will fail.1
Does the amount of bone left below the sinus decide which route is used?
At 6 mm of residual bone height or less, the review found no statistically significant difference between the two routes in survival, perforation or marginal bone loss, and patients reported greater satisfaction with the transcrestal route.1
References
- Shi S, Han L, Su J, Guo J, Yu F, Zhang W. Clinical efficacy of transcrestal sinus floor augmentation, in comparison with lateral approach, in sites with residual bone height ≤6 mm: a systematic review and meta-analysis. Clinical Oral Implants Research. 2023;34(11):1151–1175. doi:10.1111/clr.14155
This page describes published clinical practice. It is not a treatment plan, and it does not replace an examination.