ABSTRACT
Positron emission tomography(PET) is a nuclear imaging technology, which can accurately determine the local function and the biochemical course of organs or tissues of human body, so PET technology has an important role in the diagnosis of tumors and other diseases. 18F-FDG has been used in oncology for differentiating of benign tumors from malignant tumors, detecting and staging of malignant tumors. However, 18F-FDG has low specificity, no uptake in some tumor cells but appreciable uptake in inflammation. Therefore designing and synthesizing tumor imaging agents with high specificity and sensitivity is necessary and exigent. In view of the fact that the metabolism of protein is also increased in tumor tissues in addition to the metabolism of glucose, developing new amino acid imaging agents labeled by positron emission nuclide may have quite large potential.
ABSTRACT
BACKGROUND: The persistence of bone atrophy and maxillary sinus gasification can cause a deficiency in the height of maxillary posterior teeth. It is very difficult to place dental implants at this site. Increasing bone mass in the maxilla is beneficial for dental implantation, and it is a currently accepted method to lift the maxillary sinus to compensate for bone loss. OBJECTIVE: To analyze the application effect of bone graft material, human working bone material and tissue engineering scaffold material in maxillary sinus elevation. METHODS: "Maxillary sinus elevation, dental implant, autologous bone, allograft, artificial bone, scaffold" were used as the key words in Chinese and English to retrieve relevant articles concerning materials used in maxillary sinus elevation included in PubMed and WanFang. Then, we analyzed the effects of different bone grafting materials on new bone formation, implant stability and bone-implant binding rate after maxillary sinus elevation. RESULTS AND CONCLUSION: Autologous bone is the gold standard of bone graft material in maxillary sinus elevation, which can ensure the bone mass and the long-term stability of implantation around the implant, but it is easy to cause secondary damage to the donor area and to produce infection. Allogeneic bone can be used as an alternative material of autogenous bone,such as deproteinized bovine bone minerals,inorganic bovine bone,etc.,which can generate new bone and ensure dental implantation to achieve sufficient stability. Artificial bone materials such as hydroxyapatite, beta-tricalcium phosphate,biphasic calcium phosphate compound,etc.have good bone conduction and can achieve a high bone-implant contact rate. Tissue-engineered bone grafts that can combine stem cells and cytokines with bio-scaffolds for maxillary sinus elevation can promote new bone formation, increase bone mass, and ensure dental implantation to achieve good stability.