Objective:To investigate the surface characterization,cell adhension and proliferation of ultrafine grained titanium (UFG Ti) after different sand blasting and acid-etching(SLA).Methods:The billets of UFG Ti and commercially pure titanium Ti(CP Ti) were incised into cylindrical specimens with 7 mm in diameter and 2 mm in height.The specimens were sand blasted at the air pressure of 0.2,0.4,0.6 and 0.8 MPa respectively(n =10) and then acid-etched.The surface morphology,roughness and surface wettability of the specimens were examined.Rat embryo osteoblasts MC3T3-E1 were cultured on the speciments for 1 d,3 d and 5 d respectively,the cell morphology and cell density were observed.Results:The different hierarchical porous topographies were formed on the surface of UFG and CP Ti after modified by SLA.The sizes of blasted holes on the surface and the surface roughness of both materials increased with the increase of blast pressure,but the values of UFG Ti were lower than those of CP Ti correspondingly(P ＜ 0.05).The surface wettability of them was also changed with the blast pressure,but the values of UFG Ti was significantly smaller than those of CP Ti(P ＜ 0.05).When the blast pressure was 0.6 Mpa,the UFG Ti exhibited excellent wettability,the cell density was the highest,the morphology of MC3T3-E1 cells on UFG Ti was superior to that on CP Ti.Conclusion:UFG Ti exhibits proper surface morphology,roughness and excellent wettability,which is more appropriate for adhension and proliferation of MC3T3-E1 cells after modification by SLA at blast pressure of 0.6 Mpa.

Patients with impaired quality of life associated with xerostomia need long-term treatment, and a nerve stimulator has the advantage of providing natural saliva and long-term management for patients with xerostomia by electrically stimulating the relevant secretory nerves to promote saliva production. A number of clinical trials have preliminarily demonstrated the efficacy of nerve electrical stimulation in the treatment of xerostomia. However, electrical stimulation has not yet become the mainstream treatment for xerostomia. Large prospective randomized controlled clinical trials are still needed to confirm its long-term effectiveness and safety. In addition, the design of nerve stimulators is of great significance for clinical application. The large volume and inconvenient treatment associated with the extra oral nerve stimulator and the first generation intraoral nerve stimulator hinder their clinical application and popularization. The second- and third-generation intraoral nerve stimulator devices are small, convenient to use and have great application prospects. Research on electrical nerve stimulators for xerostomia treatment is mainly concentrated in European and American countries, while there is very little domestic research. It is urgent to master the core technology for the research and development of electrical nerve stimulators. The innovation of miniaturization, efficient power supply, data feedback and packaging will be the key issues of electrical nerve stimulators in the future. In this paper, the treatment and research of electrical nerve stimulation for xerostomia are reviewed to provide a reference for related basic research and the clinical application of electrical stimulators treating xerostomia in China.