Sinus Lift

The maxillary sinuses are air-filled spaces beside the nose, above the upper premolar and molar teeth. A thin lining, the sinus membrane, covers the bone inside them ^[1]. In a sinus lift, also called sinus augmentation or sinus floor elevation, this lining is gently raised and graft material is placed underneath, so that bone forms where an implant needs to go ^[1][3].

Why is the bone missing? After a back tooth is removed, the bone around the socket shrinks, most of all in the upper back jaw, and the sinus tends to expand downwards into the space, a process called pneumatisation ^[2]. This can leave too little bone between the mouth and the sinus to hold an implant ^[2][4], which is why the upper back jaw has long been one of the hardest places to place implants ^[3].

There are two main approaches:

• Lateral window (external or "open" sinus lift): a small window is made in the side of the jaw, from the cheek side; the lining is pushed up and graft material is packed below it ^[1].
• Transcrestal (internal, crestal or osteotome sinus lift): the sinus floor is gently tapped up through the hole prepared for the implant, which is placed at the same time. It is used where only around 3 mm of extra height is needed ^[1].

The graft is a scaffold that your own bone grows into. It can come from your own body, a human donor, an animal or a synthetic source; a widely used option is sterilised bovine (cattle) bone, sometimes covered by a dissolvable membrane ^[1]. If you have concerns about animal-derived products, raise them before surgery ^[1].

A sinus lift is a step within dental implant treatment, for a single tooth or as part of full mouth dental implants.

A sinus lift is a common procedure ^[1], but it is surgery next to the sinus. The figures below come from a Cambridge University Hospitals NHS patient leaflet ^[1]:

• Membrane tear: the main risk during surgery, with a 19% chance in the lateral window approach and 3.8% in the transcrestal one. A tear is usually stitched or patched; if not, the lift is stopped and can be redone once the lining has healed ^[1].
• Sinus symptoms and infection: the sinus may feel full or blocked for some weeks. Infection has a 2.9% chance with the lateral approach and 0.8% with the transcrestal one; rarely, the graft has to be removed ^[1].
• Graft failure: in 1.9% of lateral window lifts no graft remains after healing, more often in smokers; in 1%, too little bone forms for an implant ^[1].
• Rare but serious: numbness of the cheek, upper gums or teeth, usually temporary but very rarely permanent, or an opening between the sinus and the mouth ^[1].

Aftercare protects the graft:

• No nose blowing: avoid blowing your nose for two weeks ^[1].
• Medicines: take any prescribed antibiotics or decongestants, and menthol steam inhalations if advised ^[1].
• Warning signs: contact your surgeon if swelling or pain worsens after two days, bleeding does not stop, you develop a fever, or you think graft material moved after a sneeze ^[1].
• Flying: wait at least two weeks and until you have no sinus symptoms, as pressure changes in flight can inflame the sinus and put the graft at risk; travelling home by land avoids this ^[6].