Objective To compare the effects of different crown materials on the stress distribution of dental implants by finite ele-ment method.Methods A three-dimensional finite element model of implant-supported crown restoration of the right mandibular first molar was established.Four kinds of crown restoration materials were used,including polymer infiltrated ceramic network Vita Enamic,resin nanoceramic Lava Ultimate,zirconia ceramic Cercon,and polyether-ether-ketone breCAM.A displacement load of 0.01 mm or 200 N was applied to the occlusal surface of the right mandibular first molar,and the analysis of reaction force,the maximum variability of shape,the maximum principal stress,the maximum equivalent stress was performed.Results The results of stress analysis under 0.01 mm displacement load showed that the maximum equivalent stress of Cercon was 937.30 MPa,and that of breCAM was 67.09 MPa.The stress concentration of crowns and implants was obvious.The maximum equivalent stress of the surrounding alveolar bone of Cercon was the highest(26.61 MPa),and that of breCAM was the lowest(3.87 MPa),which was about 1/7 of that of maximum group.The stress concentration range of resin-matrix ceramics and polyether-ether-ketone was relatively small,and the distribution was more uniform.When 200 N was applied,the maximum principal stress and the maximum equivalent stress distribution of the four models were similar,and the maximum variability of shape of breCAM was larger at the loading site.Conclusion Under the same displace-ment load,the stress concentration of polyether-ether-ketone and resin-matrix ceramics crown was lower than that of zirconia.There was no significant difference in stress concentration in the implant and surrounding alveolar bone among polyetheretherketone,resin-ceramic composite,and zirconia crown restorations under the same load.Further research on long-term durability of PEEK and resin-matrix ce-ramicsis needed through practical and clinical trials.

Objective:To study the clinical outcome of lamellar keratoplasty combined with autogenous corneal stromal padding for treatment of corneal perforation.Methods:An observational case series study was conducted.A total of 14 patients (14 eyes) with corneal perforation underwent lamellar keratoplasty in Henan Provincial People's Hospital from January 2017 to August 2018 were collected.During the operation, the corneal stromal autograft was taken to pad the corneal perforation.Visual acuity, intraocular pressure, corneal epithelial healing time, infection recurrence, and the status of corneal graft and anterior chamber were recorded on the 1st, 7th, 14th day, 1st, 3rd, 6th, 9th and 12th month after operation.OCT examination of anterior segment was performed at 1 month, 6 and 12 months postoperatively to observe the interlamellar structure of corneal implantation bed and stromal graft, anterior chamber and iris.The safety and effectiveness of the operation were evaluated according to the 1-year follow-up.The study protocol adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[18]). Written informed consent was obtained from each patient prior to entering the study cohort.Results:The healing time of corneal epithelium was 2-4 days after operation, (3.01±0.59) days on average.At one day after surgery, all patients had normal anterior chamber depth without aqueous leak and no double chamber was observed.The corneal grafts attached to the implantation bed well and showed mild to moderate edema.There was no recurrence of corneal infection ulcer two weeks after operation, and the corneal ulcer was healed and anterior chamber was well formed in 14 patients.The corneal graft was transparent, and the anterior segment OCT image showed corneal implant bed and graft were well attached, and the anterior chamber depth was normal three months after operation.The best corrected visual acuity of 9 eyes was more than 0.3 one year after operation, and the vision acuity of the 14 patients improved obviously, and no refractory glaucoma occurred after operation.Conclusions:Lamellar keratoplasty combined with autogenous corneal stromal padding is a safe and effective surgical procedure for treating corneal perforation.

Objective To analyze the epidemiological characteristics of mycoplasma pneumoniae (MP) infection among the out-patients and inpatients children in Shenzhen area during 2010-2012 and to explore the significance of the results of the laboratory routine tests in the diagnosis of MP infection .Methods The children patients with respiratory tract infection from 2010 to 2012 were selected and the MP infection and the non-MP infection were screened out .The epidemiological characteristics of gender ,age , etc .,among the children patients with MP infection during these 3 years were analyzed .The differences in the laboratory routine tests and high sensitivity C reactive protein (hsCRP) were compared between the MP infection and the non-MP infection .Results The positive detection rate of MP-DNA in males was slightly higher than that in females ,the difference had no statistical signifi-cance (P>0 .05);MP infection occurred in different age groups ,the positive detection rate of MP-DNA was lowest in the children patients aged <1 year old and highest in the children patients aged 3 - < 6 years (P< 0 .05);the routine laboratory tests and hsCRP level had no specificity in the diagnosis of MP infection .Conclusion The MP molecular epidemiology in Shenzhen area shows that MP infection has the seasonality ,the laboratory routine tests and hsCRP level can not be used as the basis of the MP la-boratory diagnosis .

PurposeTo observe the effects of blocking the renin-Angiotensin-Aldosterone system at different sites in experimental congestive heart failure (CHF)rats. Methods Six weeks after coronary ligation, rats( n = 66)were randomized to benalapril, losartan, spironolactone, placebo, and treated for 6 weeks. Sham-operated rats( n = 18) served as controls. Six weeks later left ventricular hemodynamics were measured. Results In the hemodynamic variables, HR was not significantly different between groups. Compared four treatment groups with sham-operated group, LVEDP increased, LVPSP and ± dp/dtmax decreased (P＜0.05). Compared with placebo group,all data in spironolactone group were not significantly different, LVEDP, mortality in benalapril group and in losartan group decreased, LVPSP and ± dp/dtmax in benalapril group and in losartan group increased(P ＜ 0.05). ConclusionsAdministration of ACEI and Ag Ⅱ-AT1 antagonist are effective in preventing from cardiac function deterioration, while spironolactone treatments are not. Spironolactone has tendency in decreasing LVEDP.