Sinus lift procedure

The sinus lift procedure, also known as subantral augmentation, is performed in patients with insufficient bone stock to secure a dental implant in the maxilla. 

Procedure

The aim of the sinus lift procedure is to increase the height and width of maxillary alveolar bone (to at least 5 mm in width and 7 mm in height) by placing bone graft material in the floor of the maxillary sinus ^1,2:

• a surgical window (osteotomy) is made in buccal surface of the maxillary alveolus
• dissection and elevation of the Schneidarien membrane
• bone graft material placed into the created cavity

The bone graft may be synthetic bone substitute material (e.g. hydroxyapatite), autogenous freeze-dried bone, autogenous bone graft (from iliac crest, maxillary tuberosity, or mandibular symphysis or ramus), or a mixture of both ^1,2. Healing typically takes six months prior to the placement of a dental implant ¹.

Radiographic features

CT

One case series of 356 scans showed ¹:

• a well-integrated graft will be indistinguishable from the maxillary sinus floor
• mild adjacent soft thickening was seen as a normal finding
• in non-integration, the graft will appear as an irregular high-density mass in the inferior aspect of the sinus
• in the cases of infection, the graft material will be absent or dissipated with marked soft tissue thickening in the maxillary sinus

Differential diagnosis

Other surgical procedures used to increase the height and width of the maxillary alveolus ²:

• osteotome technique: less elevation of sinus floor and less bone graft packing
• onlay grafting: bone graft material is laid on the alveolar ridge

Unrecognised graft materialy may be confused for ¹:

• osteomas
• fibrous dysplasia
• tumours