The implant-supported prosthesis has gradually become the preferred treatment for patients with partial edentulous or complete edentulous. Causes for the implant failure have been discussed in the majority of studies conducted in recent years, while their risk factors are still controversial. Patient factors (gender, age, smoking, osteoporosis, diabetes, medication, periodontitis and bruxism), clinical parameters (implant area, bone quality, implant size) and doctor factors (surgical-related factors, prosthesis-related factors) will all affect implant failure. This article presents typical clinical cases and reviews the potential risk factors for dental implant failure, in order to provide guidance for clinical practice.

Objective : To learn the epidemiological characteristics of coronavirus disease 2019 (COVID-19) cases reported from January 21 to February 20,2020 in Zhejiang Province,so as to provide basis for formulating and implementing effective control measures. Methods : The COVID-19 cases reported by Zhejiang Province were extracted from the National Diseases Prevention and Control Information System. A descriptive analysis was adopted for the epidemiological characteristics of COVID-19 cases,including time,spatial and population distribution,severity of symptoms, and exposure history. Results : Totally 1 284 cases were reported,of which 1 176 were confirmed cases (91.59%) and 108 were asymptomatic cases (8.41%). The first confirmed case was reported on January 21. The curve of the disease onset peaked from January 22 to 29, with 87 cases as the biggest number a day. The curve of the disease reported peaked from January 28 to 30, with 130 cases as the biggest number a day. Then the number of the cases showed a declining trend. By February 4, totally 79 counties (cities, districts) had confirmed cases, covering 87.78% of Zhejiang Province, and it has not increase since then. A male to female ratio of 1.02∶1 was reported among 1 284 cases,1 021 were 30-69 years old (79.52%) and 339 (26.40%) were business service providers. There were 11 health workers reported to be infected,but not by occupational exposure. Among the confirmed cases, 1 010 (85.88%) were clinically mild cases. One case died. Before January 23, the cases were mainly imported from Hubei Province, local cases were predominant by the end of January. Conclusions The COVID-19 epidemic has spread widely in Zhejiang Province and people are generally susceptible. Most cases were clinically mild, and were aged 30-69 years. No health workers infected were due to occupational exposure. The incidence of COVID-19 in Zhejiang Province has turned into a lower level,suggesting that the early prevention and control measures have achieved initial results. With people returning from holiday, precise prevention and control should be put into effect.

Maxillary sinus augmentation is an effective procedure to gain bone height for implant placement in an atrophic posterior maxilla. But maxillary sinus diseases are prevalent in patients scheduled for sinus lift procedures. The presence of these diseases may increase the difficulties in performing the surgery and the risk of developing postoperative complications. This paper summarizes and introduces the common maxillary sinus mucosa diseases related to maxillary sinus augmentation.

The use of antibiotics in dental implantology is very common and the abuse of antibiotics is increasingly obvious. The rational use of antibiotics in the process of oral implantology needs the support of evidence based medicine. The prophylactic use of antibiotics in dental implantology is reviewed in this article, including the summary of different infection risks, such as peri-implantitis and maxillary sinusitis after maxillary sinus floor lifting.

Objective: To evaluate the clinical efficacy of modified lateral window for maxillary sinus floor augmentation (MSFA). Methods: Fifty-five patients who visited the Stomatology Hospital Affiliated to Zhejiang University School of Medicine between June 2012 and October 2014 were enrolled in the study. Patients underwent MSFA with Bio-Oss grafts based on modified access window. During the operation the vertical height of the bony window was reduced from 6-8 mm of conventional oval window to 4-5 mm of slot-shaped window. The sinus membrane was detached completely via the lateral access and large particle Bio-Oss graft was placed in the sub-mucosal space. The implant survival, graft height, graft volume and resorption rates were measured. Intra-op and post-op complications were recorded. Results: There were 86 implants inserted. The 2-4 year cumulative survival rates were 97.67% by implant-based analysis and 96.36% by patient-based analysis. The residual bone height was (4.7±2.6) mm and bone width was (8.4±2.7) mm. The bone height of implantation site immediately after operation was (16.1±2.5) mm and it was (16.2±2.2) mm at restoration. The bone heights at 1 and 2 years after operation were (14.9±2.5) mm and (13.6±2.6) mm, respectively. The graft height was (10.6±2.8) mm and the graft volume was (1569±745) mm³ immediately after operation. The resorption rate of graft height 6 months after operation was 3.79% and that of graft volume was 7.87%. The 1-year accumulative resorption rate of graft height was 6.63% and that of graft volume was 10.89%. The 2-year accumulative resorption rate of graft height was 7.58% and that of graft volume was 15.26%. Small membrane perforation during MSFA was observed in 5 cases and all were successfully repaired by a collagen Bio-Gide membrane. Conclusion: The modified lateral technique obtains high implant survival rate, excellent graft stability and low complication rate at 2-4 year clinical follow-up, indicating that it is a safe, predictable and minimally invasive surgical method for severe atrophic maxillary posterior dentition.
Dental Implantation, Endosseous ; Follow-Up Studies ; Humans ; Maxillary Sinus ; surgery ; Sinus Floor Augmentation ; methods ; Treatment Outcome