Objective·To evaluate the applicability of dual-unit cantilever restorations supported by a single narrow-diameter implant for consecutive missing teeth in the anterior mandibular region.Methods·A simplified mandibular anterior jaw model and a dual-unit cantilever model supported by a single narrow-diameter implant were constructed.The dimensions of the mandibular anterior bone block were set to 20 mm(length),5 mm(width),and 15 mm(height).The narrow-diameter implant used was the Axiom 2.8 two-stage implant,2.8 mm× 10 mm,paired with a 2.5 mm straight abutment.Based on calculations,the edentulous gap ranged from 5.8 mm to 11.6 mm,leading to the creation of seven crown models with mesiodistal widths of 5.8,6.8,7.8,8.8,9.8,10.8,and 11.8 mm.The implant,crowns,and jaw model were assembled using Siemens Nx 12.0 software,and the data were imported into Ansys Workbench 18.0 for finite element analysis.A vertical load of 100 N and a 30° oblique load were applied to simulate occlusal forces.The Von-Mises stress on the implants,as well as the maximum compressive and tensile stresses in the cortical bone and the maximum tensile stress in the cancellous bone,was analyzed to investigate stress distribution under varying cantilever lengths.Results·The implant neck region exhibited the highest stress concentration.As the cantilever length increased,the peak Von-Mises stress on the implants,the maximum tensile stress in the cortical and cancellous bones,and the maximum compressive stress in the cortical bones all increased progressively.However,all stress values remained within physiological limits.The peak Von-Mises stress ranged from 141.52 MPa to 707.17 MPa,below the implant's ultimate tensile strength of 930 MPa.The maximum tensile stress in the cortical bones(with a peak of 60.82 MPa in the 11.8 mm group)was below the cortical bone's tensile strength limit of 100-130 MPa.The maximum compressive stress in the cortical bone(with an absolute maximum value of 129.39 MPa in the 11.8 mm group)was below the cortical bone's compressive strength limit of 170 to 190 MPa(absolute values).The maximum tensile stress in the cancellous bone ranged from 0.84 MPa to 4.70 MPa,which was below or close to its ultimate tensile strength of 2-5 MPa.Conclusion·Dual-unit cantilever restorations supported by a single narrow-diameter implant may represent a viable treatment option for consecutive missing teeth in the anterior mandibular region.

Objective·To evaluate the applicability of dual-unit cantilever restorations supported by a single narrow-diameter implant for consecutive missing teeth in the anterior mandibular region.Methods·A simplified mandibular anterior jaw model and a dual-unit cantilever model supported by a single narrow-diameter implant were constructed.The dimensions of the mandibular anterior bone block were set to 20 mm(length),5 mm(width),and 15 mm(height).The narrow-diameter implant used was the Axiom 2.8 two-stage implant,2.8 mm× 10 mm,paired with a 2.5 mm straight abutment.Based on calculations,the edentulous gap ranged from 5.8 mm to 11.6 mm,leading to the creation of seven crown models with mesiodistal widths of 5.8,6.8,7.8,8.8,9.8,10.8,and 11.8 mm.The implant,crowns,and jaw model were assembled using Siemens Nx 12.0 software,and the data were imported into Ansys Workbench 18.0 for finite element analysis.A vertical load of 100 N and a 30° oblique load were applied to simulate occlusal forces.The Von-Mises stress on the implants,as well as the maximum compressive and tensile stresses in the cortical bone and the maximum tensile stress in the cancellous bone,was analyzed to investigate stress distribution under varying cantilever lengths.Results·The implant neck region exhibited the highest stress concentration.As the cantilever length increased,the peak Von-Mises stress on the implants,the maximum tensile stress in the cortical and cancellous bones,and the maximum compressive stress in the cortical bones all increased progressively.However,all stress values remained within physiological limits.The peak Von-Mises stress ranged from 141.52 MPa to 707.17 MPa,below the implant's ultimate tensile strength of 930 MPa.The maximum tensile stress in the cortical bones(with a peak of 60.82 MPa in the 11.8 mm group)was below the cortical bone's tensile strength limit of 100-130 MPa.The maximum compressive stress in the cortical bone(with an absolute maximum value of 129.39 MPa in the 11.8 mm group)was below the cortical bone's compressive strength limit of 170 to 190 MPa(absolute values).The maximum tensile stress in the cancellous bone ranged from 0.84 MPa to 4.70 MPa,which was below or close to its ultimate tensile strength of 2-5 MPa.Conclusion·Dual-unit cantilever restorations supported by a single narrow-diameter implant may represent a viable treatment option for consecutive missing teeth in the anterior mandibular region.

Objective: To discuss the prevalence and influential factors of stroke among population in Jiangxi Province. Methods: Four cities in urban areas and four counties in rural areas were selected firstly, in which two districts or townships were selected; and then three communities or villages were chosen from each district and township, respectively, using the simple random sampling (SRS) method. Finally 15 269 subjects aging 15 years old or above, living in Jiangxi Province ≥6 months were randomly selected to participate in this survey from November 2013 to August 2014. Information of population characteristics, life behavior way, individual disease history were collected through questionnaire survey, and height, weight, waist circumference, blood pressure, body fat rate, visceral fat index and so on were measured by instruments. Risk factors of stroke prevalence were analyzed by the unconditioned logistic regression analysis. Results: A total of 15 269 participants (6 267 males) from 15 364 eligible participants were included in the statistical analysis. Out of which, 7 793 participants came from urban areas, and their average age was (53.04±17.91) years old. In this study, 226 stroke patients (117 males) were found among15 269 participants, including 122 urban participants and 104 rural participants, whose average age was (67.76±9.74) years old. The prevalence of stroke was 1 480.12/100 000 in 2014, which was separately 1 866.92/100 000 and 1 210.84/100 000 among males and females. The prevalence of people aging (45-49) years old was 413.79/100 000 (6/1 450) , while which among people aging 75 years old and above was 3 311.62/100 000 (61/1 842) . The prevalence of stroke among residents in Jiangxi presented an uprising tendency with age increasing (linear-by-linear association χ²=62.23, P<0.01). The research showed that when other influencing factors including gender, BMI, waist circumference, pulse-pressure difference, VAI, and sleeping time in non-working days were controlled, hypertensive patients had a higher risk of stroke than people without hypertension (OR=6.88, 95%CI: 4.90-9.67), drinkers had a higher risk of stroke than non-drinkers (OR=1.56, 95%CI: 1.17-2.08), compared with people <65 years old, people aged 65-74 years old and ≥75 years old had a higher risk of stroke, the value of OR (95%CI) were 1.88 (1.36-2.59) and 1.97 (1.39-2.80), respectively, compared with people with normal body fat percentage, people whose body fat percentage on high side and people who with high body fat percentage had a higher risk of stroke, the value of OR (95%CI) were 1.71 (1.18-2.48) and 1.74 (1.18-2.56), respectively, people with sleep time >8 h had a higher risk of stroke than those with sleep time of 6-8 h. Conclusion There was a high stroke prevalence among residents in Jiangxi province. Hypertension, drinking, age, BFP and sleep duration were associated with stroke prevalence. Corresponding measures for high-risk population and risk factors should be strengthened to prevent and control the stroke.