The maxillary sinus and the arteries around it

Sinus lift: what happens when there is an air cavity where your bone should be

In the upper back jaw the maxillary sinus sits directly above the roots, and when it drops there is no height to place into. Two approaches exist, one considerably harder than the other.

How it is done here ONE Dental Clinic

The publisher is a registered patient facilitator, paid by clinics when a reader becomes a patient through its agency. How we make money

Above your upper molars is the maxillary sinus, an air cavity. When an upper back tooth is lost, the sinus tends to expand downwards into the space, and the bone between the sinus floor and your gum thins until a fixture will not fit.

A sinus lift raises the sinus floor, packs bone graft into the space created, and gives a fixture somewhere to go. The radiographs on this page show the same jaw before and after, with the sinus floor and the gum bone height marked, which is the clearest way to understand it.

Crestal approach

The surgeon works upwards through the ridge itself, along the direction the tooth root used to run, lifting the sinus membrane from below and placing graft through the same channel. The clinic grades this high difficulty. It is less invasive and works where the shortfall in height is modest.

Lateral window approach

The surgeon opens a window in the outer wall of the maxilla, just below the cheekbone, lifts the sinus membrane through it, and fills the space. The clinic grades this highest difficulty. It is used when a lot of height has to be created, and it gives direct vision of the membrane, which is exactly what is most likely to tear.

Sinusitis first

The clinic’s own case on this page is a patient with marked maxillary sinusitis. The sinus was cleared with medication first and the implant was placed afterwards. That order is the point. Lifting an infected sinus invites the infection into the graft, and a clinic that checks and treats before operating is doing the unglamorous thing correctly.

Crestal approach: Through the ridge, along the old root direction. Graded high difficulty.
Lateral window: Through the outer wall below the cheekbone. Graded highest difficulty.
Chosen by: How much vertical height has to be created.
Before either: The sinus must be healthy. Sinusitis is treated first.
Imaging: 3D CT, always.

Limits, risks and who this is wrong for

The commonest complication is perforation of the sinus membrane during lifting. Small perforations are often repaired during the same operation; larger ones can mean abandoning the graft and returning months later.

Other documented risks: sinus infection, graft material migrating into the sinus, bleeding, prolonged swelling, and failure of the graft to form usable bone.

Afterwards you will be told not to blow your nose, not to fly for a period, not to use a straw and to sneeze with your mouth open. If your return flight is inside that window, the surgery date has to move, not the instruction. Raise this before it is booked.

A sinus lift is not for everyone with a thin upper jaw. Short implants, described elsewhere on this site, sometimes remove the need for one entirely.

Clinical photographs

Radiographs before and after the sinus floor is raised

A step chart of sinus lift and bone grafting, with the maxillary sinus marked on a profile

Three stages of a crestal sinus lift shown in section

Crestal approach, step one: the osteotome enters along the old root axis

Crestal approach, step two: the sinus membrane is lifted and graft placed

Crestal approach, step three: the fixture is placed in the new height

Why a fixture cannot be placed without lifting the sinus, in four panels

Lateral window approach, step one: a window is opened in the outer wall

Lateral window approach, step two: graft material fills the lifted space

Lateral window approach, step three: fixtures placed through the grafted bone

Radiograph showing marked maxillary sinusitis before treatment

The same sinus clear after medication, before implant placement

This article is information, not medical advice, and reading it does not create a doctor-patient relationship. The Seoul Glow is a registered facilitator: we coordinate care, we do not practise medicine and we do not decide what treatment is right for you. No outcome can be guaranteed by anyone. Discuss any procedure with a licensed physician who has examined you.