Sinus floor elevation — open and closed sinus lift

Sinus lift (sinus floor elevation) is a surgical procedure that involves raising the floor of the maxillary sinus and filling the resulting space with bone graft material from a tissue bank. The goal is to obtain sufficient bone height in the posterior maxilla to allow placement of an implant of adequate length.

It is one of the most commonly performed pre-implant procedures in maxillofacial surgery. I perform it regularly in patients where bone loss in the premolar or molar region of the upper jaw prevents standard implant placement. The procedure has a well-established position in implantology and decades of clinical evidence confirming its effectiveness.

Maxillary sinus and alveolar ridge — anatomy

The maxillary sinus (sinus maxillaris) is the largest of the paranasal sinuses — an air-filled cavity within the body of the maxilla, located on both sides of the nose, directly above the roots of the upper posterior teeth. Its interior is lined with a thin mucous membrane known as the Schneiderian membrane.

The floor of the maxillary sinus is separated by only a few millimeters of bone from the apices of the premolar and molar roots. After these teeth are lost, two parallel processes begin: resorption of the alveolar ridge (the bone atrophies "from below" as it is no longer loaded by chewing forces) and pneumatization of the sinus (the sinus expands its volume "from above," lowering its floor). As a result, the layer of bone between the ridge crest and the sinus floor gradually diminishes — sometimes to a level that precludes implant placement without prior augmentation.

When is a sinus lift needed?

I consider sinus floor elevation in the following situations:

• planned implant placement in the posterior maxilla (premolar and molar region) where the native bone height is insufficient for implant placement
• long-term tooth loss in this region, leading to advanced ridge resorption and sinus pneumatization
• naturally low-lying sinus floor, even with relatively recent tooth loss
• the need for implants of a length that ensures long-term stability in a region subject to high occlusal forces

The decision on the need for a sinus lift and the choice of technique (open or closed) is based on CBCT scan analysis, which allows precise assessment of native bone height, Schneiderian membrane thickness and condition, and sinus anatomy.

Closed sinus lift

The closed sinus lift is a less invasive technique. Access to the sinus floor is gained from the crest of the alveolar ridge, through the prepared implant osteotomy — without the need to prepare a separate bone window.

Procedure: after local anesthesia, I prepare the implant osteotomy to a depth just below the sinus floor. Then, using specialized instruments, I carefully elevate the sinus floor along with the Schneiderian membrane while simultaneously introducing bone graft material from a tissue bank into the space beneath the elevated membrane. An implant is placed into the prepared site — its apex is surrounded by the graft material, while its body is stabilized in the existing native bone.

I use this technique when the native bone height is above 4 mm — enough for the implant to achieve primary stability, yet insufficient for an implant of optimal length without augmentation. The typical bone gain is 4-10 mm.

The procedure takes approximately 30-60 minutes. The main advantage of the closed technique is the possibility of simultaneous implant placement — the patient undergoes one procedure instead of two, and the implant and augmentation heal in parallel over 3-6 months.

Open sinus lift — lateral window approach

The open sinus lift (lateral window technique) is a more extensive procedure, but it allows for significantly greater bone gain — exceeding 10 mm.

Procedure: after local anesthesia, I expose the lateral wall of the maxilla through an incision in the oral mucosa. In the bone wall, I prepare a window (osteotomy), through which I carefully dissect and elevate the Schneiderian membrane from the sinus floor. The resulting space is filled with bone graft material from a tissue bank (allograft bone). Allograft bone is human bone from a donor, processed and sterilized at a certified tissue bank. Its structure closely resembles the patient's own bone, which promotes biological remodeling — the body gradually replaces the graft material with its own living bone. In selected cases, I also use platelet concentrates (CGF/PRF) to support healing. The bone window is covered with a collagen membrane.

I use the open technique when the native bone height is below 4 mm — too little to provide implant stability without prior augmentation. Implant placement is usually deferred: after 4-6 months of healing, once the newly formed bone has integrated, I place the implants in a separate procedure. In some cases, when there is enough native bone to achieve primary implant stability, simultaneous implantation is possible.

The procedure takes approximately 60-90 minutes. The healing period is longer than with the closed technique, but the extent of possible augmentation is significantly greater.

Comparison of both techniques

Aspect	Closed sinus lift	Open sinus lift
Surgical access	Through the implant osteotomy	Through a window in the lateral sinus wall (above the missing tooth site)
Bone gain	4-10 mm	Over 10 mm
Simultaneous implantation	Usually yes	Depends on the case (often deferred)
Invasiveness	Lower	Higher
Procedure duration	30-60 min	60-90 min
Healing	3-6 months (together with the implant)	4-6 months (then separate implant placement)
Primary indication	Native bone above 4 mm	Native bone below 4 mm

The choice of technique is not a matter of preference — it results from objective anatomical parameters assessed on the basis of CBCT imaging. In practice, I perform both techniques, selecting them according to the specific clinical situation of each patient.

Preparation for the procedure

The basis for qualification for a sinus lift is a CBCT scan, which allows assessment of native bone height, Schneiderian membrane thickness and continuity, the presence of any sinus pathology (polyps, cysts, mucosal changes), and overall sinus anatomy. If I identify abnormalities requiring prior ENT treatment, I refer the patient to a specialist before the planned procedure.

Before the visit, it is helpful to have a recent CBCT or panoramic radiograph. If the patient does not have one, we take it on site at the office. During the consultation, I discuss the procedure plan, the expected extent of augmentation, the possibility of simultaneous implant placement, and the estimated treatment timeline.

After the procedure — recommendations and healing

The postoperative course after a sinus lift is similar to other oral surgery procedures, with several important differences arising from the proximity of the maxillary sinus.

Swelling and discomfort

Swelling of the cheek on the operated side is a natural response and peaks on postoperative days 2-3. We prescribe pain medications (ibuprofen, paracetamol, or their combination) and antibiotics. In selected cases, I recommend nasal decongestant drops to facilitate drainage.

Key recommendations

• Do not blow your nose for at least 2-3 weeks — increased pressure in the nasal cavity can damage the elevated Schneiderian membrane or displace the bone graft material
• Sneeze with your mouth open — for the same reason
• Avoid physical exertion for 7-10 days
• Soft diet for the first few days after the procedure
• Hygiene — gentle brushing, chlorhexidine rinse as directed

Most patients return to normal professional and social activities within 3-5 days. I schedule follow-up appointments at 10-14 days (suture removal), and then as needed. Full integration of the graft material with the patient's native bone takes 4-6 months.

Complications

Sinus floor elevation is a highly predictable procedure, but like any surgical procedure, it carries some risk of complications.

Schneiderian membrane perforation — the most common complication, occurring in approximately 10-30% of cases (depending on anatomy and technique). In most situations, the perforation is small and resolved intraoperatively — I cover it with a collagen membrane and continue the procedure. In cases of larger perforations, the procedure may need to be deferred.

Maxillary sinusitis — a rare postoperative complication requiring antibiotic treatment and, in exceptional cases, surgical intervention.

Failure of graft integration — occasionally, the graft does not integrate with the patient's native bone to the expected degree, which may require repeating the procedure.

Sinus lift and full-arch reconstructions

It is important to distinguish between two clinical situations in which posterior maxillary bone loss has different therapeutic implications.

For single missing teeth in the posterior maxilla, a sinus lift is the standard approach and usually the only way to obtain sufficient bone for an implant. There is no alternative in the form of extraosseous anchoring implants (zygomatic/pterygoid) — these are intended exclusively for full-arch reconstructions.

The situation is different with edentulism or extensive tooth loss qualifying for full-arch reconstruction such as All-on-4 or All-on-6. In cases of advanced maxillary bone loss, there is an alternative clinical pathway — instead of bone augmentation (including sinus lift) and months of waiting for healing, in selected situations zygomatic or pterygoid implants can be used. These anchor in bone structures beyond the alveolar ridge (zygomatic bone, pterygoid process of the sphenoid bone) and allow immediate prosthetic loading. This is not a "better" or "worse" solution than a sinus lift — it is a different pathway, selected individually depending on anatomy, patient expectations, and the prosthetic plan.

Zygomatic and pterygoid implants — more information

All-on-4 vs All-on-6 — comparison of methods

Smile in one day — what the surgery day looks like

Bone regeneration — guided bone regeneration (GBR)