What is Sinus Lift? Who is it Suitable For?

Why the Back of the Upper Jaw Runs Short of Bone

The back of the upper jaw often lacks the bone height an implant needs, and a sinus lift is the procedure that rebuilds that height. Implant treatment replaces a missing tooth root with a titanium screw anchored in bone, so the screw needs enough bone around it to become stable. In the molar and premolar region of the upper jaw, that bone sits directly beneath the maxillary sinus, an air-filled space lined by a thin membrane. When the bone between the mouth and the sinus floor becomes too thin, there is nowhere to anchor the implant safely.

Several processes reduce that height. After a tooth is lost, the bone that used to hold its root gradually shrinks, and the longer the gap stays without a replacement, the more height is lost. Periodontal disease destroys supporting bone before the tooth is even lost. Age-related bone loss and conditions such as osteoporosis can add to the change. Some people also have a naturally large sinus that extends low toward the tooth roots, leaving little bone even without any disease.

A patient with healthy gums can therefore still be told that the bone height at the planned implant site is too low. That finding means the height has to be created first, or at the same time as the implant.

How a Sinus Lift Creates Implant Height

A sinus lift raises the membrane that forms the sinus floor and fills the space created underneath it with bone graft. The membrane, called the Schneiderian membrane, is lifted gently from the bone without tearing it where possible. The graft material is packed into the new space between the raised membrane and the original sinus floor. Over the following months the graft integrates with the surrounding natural bone, and the region gains the vertical volume needed to hold an implant.

The procedure follows a planned sequence. A panoramic X-ray or a tomography scan is taken first to measure bone height and show the shape of the sinus. Local anaesthesia is given, so the surgery itself is not painful. The membrane is lifted, the graft is placed, and, if there is enough bone for the implant to be stable on the day, the implant can be placed in the same session. Otherwise the implant is placed later, once the graft has matured.

Healing before the implant is fully fixed averages 4 to 6 months. During this period the graft is gradually remodelled into bone tissue in the area where it was placed. The timeline depends on how much height was added, which technique was used and how the patient heals, so the dentist confirms readiness on follow-up imaging rather than by the calendar alone.

Closed and Open Sinus Lift Techniques

The choice between the two techniques depends mainly on how much bone remains under the sinus. The closed, or transcrestal, sinus lift is used when the residual bone height is about 5 mm or more. The surgeon works through the small opening prepared for the implant itself, pushes the sinus floor and membrane upward from below, and places graft material through the same channel. Because there is enough bone to hold the implant firmly on the day, the implant is usually placed in the same session. The approach is less invasive and healing is generally faster.

The open, or lateral, sinus lift is used when bone height is very low. A small window is opened in the side wall of the upper jaw above the teeth, the membrane is lifted through that window, and graft material fills the space beneath it. The implant is usually placed later, after the graft has integrated. It requires more surgical experience and a longer overall timeline.

Placing the implant in the same session has been measured directly. A systematic review of 22 clinical studies covered 864 implants placed at the same time as a graft-free sinus floor elevation, at sites with a mean residual bone height of 5.7 mm, and reported mean implant survival of 97.9% (PubMed 28168901). The same review reported a mean vertical bone gain of 3.8 mm, and this gain was affected by the surgical approach and the implant length (PubMed 28168901). These figures come from graft-free lifts, so they describe the simultaneous approach in general terms and do not replace an individual assessment.

Bone Graft Materials Used in a Sinus Lift

Four classes of graft material are used in sinus lifting, and all of them serve the same purpose, which is building bone volume under the raised membrane. An autogenous graft is taken from the patient's own bone, usually from another area of the jaw. It contains the patient's own bone cells, and its drawback is the need for a second surgical site. An allograft is human-derived bone that has been processed and sterilised by a tissue bank.

A xenograft is animal-derived, usually from bovine bone. It is processed so that only the mineral scaffold remains, and new bone grows into that scaffold over time. A synthetic graft is an artificial bone substitute produced in a laboratory.

The choice changes how the material handles and how quickly it remodels. The objective stays the same in every case. The surgeon considers the amount of height needed, the technique being used, the patient's preference about a second surgical site and the patient's general health when choosing the material. The integration period that follows is what turns the graft into a stable base, and it is the reason the implant is either placed with care on the same day or scheduled after a waiting period.

Membrane Perforation and Other Complications

Membrane perforation is the complication discussed most often in sinus lifting, and measured data show that it is common and usually manageable. A systematic review of 1,598 lateral-window sinus lift surgeries, which allowed the placement of 3,604 implants, recorded a membrane perforation rate of 30.6% (PubMed 34250560). In the same review, 1,115 implants placed under perforated and repaired membranes survived at 97.68%, while 2,495 implants placed under intact membranes survived at 98.88% (PubMed 34250560). The authors concluded that membrane perforation with the lateral approach was not a risk factor for implant survival (PubMed 34250560).

When a tear occurs, it is repaired during the same operation, most often with a collagen membrane, and the procedure continues. The size of the perforation is what determines the right repair approach, so the surgeon assesses it before deciding how to proceed.

Other complications are possible, as with any surgery. Infection, bleeding, failure of the graft material to integrate and, less commonly, loss of the implant can occur. Good oral hygiene, careful planning and keeping follow-up appointments reduce these risks. If a graft does not integrate, the procedure can be repeated or a different treatment approach can be planned. Pain or swelling that keeps increasing after the first days is a reason to contact the clinic promptly.

Recovery After a Sinus Lift

Most of the discomfort after a sinus lift is concentrated in the first 48 hours, when mild swelling and pain are expected. Nosebleeds, sneezing or nasal congestion may also occur as the sinus settles, and these usually ease within days. Antibiotics and pain relief are prescribed and should be taken on schedule.

The graft needs protection from pressure changes while it integrates. Forceful nose blowing is avoided, because it pushes air against the healing membrane. If a sneeze cannot be held back, sneezing with the mouth open reduces the pressure on the sinus. Diving, heavy exercise and any activity that raises sinus pressure are postponed during the healing period. Very hot foods are avoided in the first week.

Smoking is stopped, since it slows healing and reduces blood supply to the graft. Follow-up appointments are kept even when everything feels normal, because they are when the dentist checks the wound, removes stitches if needed and later confirms on imaging that the graft has matured. The integration phase runs 4 to 6 months on average, after which the grafted site is ready for implant placement or, if the implant was placed at the same time, for the final tooth.

Findings That Decide Candidacy for a Sinus Lift

A sinus lift is indicated when missing teeth in the back of the upper jaw are to be replaced with implants and the bone under the sinus is too low to hold them. A lift is considered when the bone height at the planned implant site is under 4 mm, and results are generally successful in the 2 to 5 mm range. Above roughly 5 mm, the closed transcrestal technique is usually enough, often with the implant in the same session. A wide or low sinus and a history of an implant that failed in this region can also point toward the procedure.

The examination looks for specific answers. The first is the exact bone height and width at each planned implant site, measured on panoramic X-ray or tomography. The second is the health of the sinus itself, since an active sinus infection is treated before surgery. The third is the condition of the gums and the remaining teeth, because active periodontal disease raises the risk for any implant. The fourth is general health, including smoking and conditions that affect healing.

When these answers are clear, the dentist can say whether a lift is needed, which technique fits, whether the implant can go in on the same day and how long the whole treatment is likely to take.

The procedure itself, from the first scan to the final implant, is set out step by step in our complete guide to sinus lift surgery before dental implants.