To analyze the accuracy of implant position in simple cases by freehand. Ninety-seven implants of 68 patients from 3 surgeons were selected.After operation,the deviations of implant position at shoulder apex and angle were measured using cone-beam CT(CBCT).The mean of three parameters were calculated with SPSS 22.0 software package, and the differences were analyzed between three surgeons,three operation areas,free-end missing and non free-end missing. The deviations of 97 implants were (0.76±0.57)mm，(1.41±0.90)mm，(4.76±3.68)° at shoulder, apex and angle.The deviation of shoulder apex and angle between three surgeons was significantly different(P<0.05). The deviations between left and right group were not significantly different (P>0.05); the deviations between anterior group and left group were significantly different(P<0.05); the deviations between anterior group and right group were not significantly different(P>0.05). The deviation of shoulder between free-end missing area and non free-end missing area was significantly different(P<0.05),other parameters between the two groups were not significantly different(P>0.05). The deviation of implant placement between surgical guide and mental guide were similar in simple cases. The experience of surgeon was important during freehand implant placement. The deviations were lower when missing tooth is in anterior area than in posterior area, whereas the same at shoulder in non free-end missing area than in free-end missing area. The deviation of implant placement between surgical guide and mental guide were similar in simple cases. The experience of surgeon was important during freehand implant placement. The deviations were lower when missing tooth is in anterior area than in posterior area, whereas the same at shoulder in non free-end missing area than in free-end missing area.During the outbreak of novel coronavirus pneumonia (NCP), dentists are at risk for more severe infection due to their professionalism. This article analyzed the route of infection during diagnosis and treatment of oral diseases. Following the related standards and guidelines of National Health Commission, the types, evaluation index and standards of medical and protective masks were summarized. It is expected to provide certain reference for the selection and use of masks of dental medical staff.The announcement of National Health Commission on January 20, 2020 (No.1 of 2020) has included novel coronavirus pneumonia into the B class infectious diseases according to the law of the People's Republic of China on the prevention and control of infectious diseases, and has been managed as A class infectious diseases. People's governments at all levels and health administration departments have been paying high attention to it. With the alleviation of COVID-19 nationwide, dental clinics gradually resume to work. The main transmission routes of COVID-19 are respiratory droplets and contact transmission, hence oral radiological examination is kind of a high-risk operation. Standardized radiologic process is of great significance to reduce the risk of COVID-19 transmission. In accordance with the national and Shanghai epidemic prevention requirements, and in combination with the actual situation of various medical institutions, Oral and Maxillofacial Radiology Committee of Shanghai Stomatological Association formulated the expert consensus on standardized prevention and control of COVID-19 for clinical reference. This recommendation will be updated according to the situation of epidemic prevention and control in China and the new relevant diagnosis and treatment plans. To investigate the effect of Bio-Oss bone powder combined with platelet-rich fibrin on bone mass after implantation-guided bone regeneration in alveolar bone defects. One hundred and six patients with single anterior tooth loss and labial alveolar bone defect were selected for implant implantation and guided bone regeneration at the same time. Patients in the experimental group (n=53) were treated with Bio-Oss bone powder combined with platelet-rich fibrin and biofilm to guide bone regeneration, while patients in the control group(n=53) were treated with Bio-Oss bone powder combined with biofilm to guide bone regeneration. The success rate of implantation, complication rate, the thickness of labial bone wall and the regeneration of bone defect were observed. Statistical analysis was performed on the data using SPSS 25.0 software package. There was no significant difference in the success rate of implants between the two groups(96.23% vs 88.68%, P>0.05). The thickness of the labial bone wall of the exelet-rich fibrin can reduce bone loss and promote bone defect regeneration after guided bone regeneration. To study the relationship between atrophic glossitis and anemia, anemia types and other related factors(oral candida infection, xerostomia) in 124 consecutive cases. One hundred and twenty-four cases with atrophic glossitis and 53 healthy controls were collected from Qingdao local population. The main indexes including general status, oral examination findings, hemoglobin (Hb), mean red blood cell volume (MCV), vitamin B12, ferritin, folic acid, anemia and anemia type, xerostomia and candida infection were statistically analyzed using SPSS 20.0 software package for Student's t test. Among 124 cases of glossitis group, 48.39% were found with anemia, 41.94% with xerostomia, 79.03% with Candida infection, 29.03% with Vitamin B12 deficiency, 22.58% with ferritin deficiency, 11.29% with folic acid deficiency. The contents of hemoglobin, ferritin and vitamin B12 in glossitis group were significantly lower than those in the control group(P<0.05), and the number of glossitis patients with anemia, xerostomia and candida infection were significantly higher than those in the control group (P<0.05). There was no significant difference in folic acid content between the two groups(P<0.05). Occurrence of atrophic glossitis is closely related to anemia, vitamin B12 deficiency, ferritin deficiency, xerostomia, oral candida infection. https://www.selleckchem.com/products/Monensin-sodium-salt(Coban).html There is no correlation with folic acid deficiency. Patients with atrophic glossitis accompanied by anemia have a higher proportion of macrocytic anemia. Occurrence of atrophic glossitis is closely related to anemia, vitamin B12 deficiency, ferritin deficiency, xerostomia, oral candida infection. There is no correlation with folic acid deficiency. Patients with atrophic glossitis accompanied by anemia have a higher proportion of macrocytic anemia.