The main goal of the Sinus-lifting procedure is to create acceptable conditions for putting implants. For sufficient strength, the implant needs a good "base" in which it will be placed.
During sinus-lifting, surgical growth of the bone tissue is carried out with special materials, because bone atrophy is possible as a result of the long-term absence of a tooth.
Remember, the bone must be at least 4mm, therefore it is recommended not to delay implant placement after tooth extraction.