When a tooth is lost, the alveolar process begins to change. The vacant tooth socket collapses as it heals, leaving an edentulous area, commonly referred to as a ridge. This collapse causes a loss—in both height and width—of the surrounding bone. In addition, when a maxillary molar or premolar is lost, the maxillary sinuspneumatizes in this region, which further diminishes the thickness of the underlying bone.[3] Overall, this leads to a loss in the volume of bone that is available for implantation of dental implants, which rely on osseointegration, to replace missing teeth. The goal of the sinus lift is to graft extra bone into the maxillary sinus so that more bone is available to support a dental implant.[4]
^Boyne, PJ. De novo bone induction by recombinant human bone morphogenetic protein-2 (rhBMP-2) in maxillary sinus floor augmentation. J Oral Maxillofac Surg 2005;63:1693-1707
^Wagner, F; Dvorak, G; Nemec, S; Pietschmann, P; Figl, M; Seemann, R (January 2017). "A principal components analysis: how pneumatization and edentulism contribute to maxillary atrophy". Oral Diseases. 23 (1): 55–61. doi:10.1111/odi.12571. PMID27537271.