Patient guide · For patients
Short implant or sinus lift? When bone is limited in the back of the upper jaw: what comparative studies report, the limits, and how the choice is made.
Many people planning an implant in the back of the upper jaw hear the same sentence: "There isn't enough bone — you need a sinus lift first." Over the past decade, however, a substantial body of research has looked at the question from another angle: instead of building the bone up, can a short implant that fits the existing bone reach a similar goal in suitable cases? This article walks through the choice between a short implant and a sinus lift, with what the literature reports and where its limits lie.
One Anatomy. Two Surgical Philosophies.
When bone height in the upper back jaw is limited, two different paths can be taken. Both are documented in the literature. Which one fits depends on the anatomy, the available bone and the patient.
Atrophic posterior maxilla: after tooth loss, bone height decreases and the sinus floor moves closer to the mouth.
Lateral window sinus floor elevation
Short implant + internal (transcrestal) sinus lift
| Augmentation-driven path | Anatomy-driven path | |
|---|---|---|
| Surgical access | Side wall of the sinus | Implant site |
| Graft volume | Large | Limited, autogenous if needed |
| Implant length | Usually standard / long | Short |
| Timing | Same session or staged | Usually same session |
Two philosophies, one goal:
Minimally invasive implantology.
Just above the upper molars lies the maxillary sinus, an air-filled space. After teeth are lost, two things tend to happen together: the jawbone loses height because it no longer carries chewing load, and the sinus floor can gradually expand downwards. The distance between the ridge in the mouth and the sinus floor may shrink to a few millimetres.
If a standard-length implant (usually 10 mm or more) no longer fits into that distance, there are two basic routes: raise the sinus floor to make room for the implant, or choose the implant according to the bone that is already there.
The open (lateral) sinus lift is the larger surgical route. A small window is opened in the side wall of the sinus, the sinus membrane is gently lifted and bone graft is placed underneath. The implant goes in at the same session or after the graft has matured. It is a well-documented method and may be necessary when very little bone height remains.
The closed (internal) sinus lift is an intermediate option. The sinus floor is raised by a few millimetres through the implant site itself, using instruments called osteotomes; no side window is opened. You can read more on the internal sinus lift page.
The short implant leaves the sinus untouched and is chosen to fit the existing bone. In the literature, implants of 8 mm or less are generally called "short" and those of 6 mm or less "extra-short". This is where the core question of the minimally invasive approach comes in: can the goal be reached with less surgery in this particular case?
This question has been studied directly in randomized controlled trials. A systematic review of eight randomized trials pooled survival at 16–18 months of follow-up at 99.5% for longer implants in grafted sinuses and 99.0% for short implants. Complications were mostly intraoperative sinus membrane perforations and were about three times more frequent with longer implants in the grafted sinus; patient-reported outcomes, surgical time and morbidity generally favoured the short implants (Thoma 2015). The authors also note that all studies were performed in specialised clinical settings.
For longer follow-up, one of the most cited studies is a multicentre randomized trial. A total of 101 patients with 5–7 mm of bone height in the posterior maxilla received either a 6 mm short implant or an 11–15 mm implant with sinus grafting. At five years of loading, patient-level survival was 98.5% in the short-implant group (one implant lost) and 100% in the grafted group, a difference that was not statistically significant. Mean marginal bone level change was 0.54 mm and 0.46 mm, and no significant differences were found in biological and technical complications or in patient-reported quality of life (Thoma 2018).
These findings do not mean that "a short implant is always enough". What can be said is this: in selected cases and with follow-up of up to five years, the two routes have been reported to give comparable results, while the short-implant route means shorter and less extensive surgery. For more detail, see the short implants page.
If bone height is borderline even for a short implant, yet not so low that an open sinus lift is needed, the closed technique may be considered. A systematic review pooling nineteen studies estimated three-year survival at 92.8% for implants placed with this method and found the results comparable to implants in non-grafted sites. In a patient-level analysis, the same review estimated that about 10.5% of patients experienced implant loss within three years (Tan 2008). The closed technique, too, depends on careful case selection.
In practice the two minimally invasive options are sometimes combined: a short implant can be paired with a few extra millimetres gained through the closed technique.
The other side of the literature is clear as well. The ITI consensus report gives survival for implants of 6 mm or less at 86.7–100% over 1–5 years, compared with 95–100% for standard implants, and notes that short implants show higher variability and lower predictability. Its conclusion is that short implants are a valid option to avoid the possible morbidity of augmentation, provided this variability is kept in mind (Jung 2018).
The open sinus lift, for its part, was judged a predictable method by the authors of a systematic review covering 48 studies and more than 12,000 implants (Pjetursson 2008). A sinus lift is therefore neither "outdated" nor "unnecessary"; in some situations it is the better option:
In addition, most comparative studies have follow-up of five years or less; longer-term data are still accumulating.
In suitable cases, yes. If bone height is above a certain threshold, a short implant or an internal sinus lift may make an open sinus lift unnecessary. Whether this is possible is decided after examination and 3D imaging.
In randomized trials of selected cases with up to five years of follow-up, no significant difference in survival was reported (Thoma 2018). Short implants do, however, show more variable results (Jung 2018), so case selection, prosthetic design and regular check-ups matter.
Because there is no need to wait for a graft to mature, the overall time can often be shorter, and studies have reported shorter surgical time in favour of short implants (Thoma 2015). The timing of the prosthetic stage is decided after examination, according to bone quality and the initial stability of the implant.
There is no single right answer to "short implant, internal sinus lift or open sinus lift?"; the right option is decided after a clinical examination and 3D imaging. A pre-assessment can start from a panoramic X-ray or CBCT you already have; the examination process is described on the implant dentist in Izmir page. Consultations are possible in Turkish and Persian.
This article is for general information and does not replace an examination or a personal treatment plan.
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