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Objective:To investigate the wear characteristics of bovine enamel and lithium disilicate glass ceramic under simulated oral environment.Methods:18 cylindrical lithium disilicate glass-ceramic specimens with the length of 8 mm and diameter of 3 mm were randomly divided into 2 groups (n =9),9 lithium disilicate glass-ceramic specimens and 9 bovine enamel specimens were served as the antagonists respectively.The specimens were then loaded in a wear simulator and subjected to friction force of 10 N for 540 000 cycles in artificial saliva and room temperature(speed 100 r/min,turning radius of 2.5 mm,uniform circular motion) condition.During the testing,10 checkpoints were applied to measure the height loss of the specimens with 3D profilometer,then wear curves were plotted.Scanning electron microscopy were applied to investigate the worn surfaces at different wear stages.Results:At every checkpoints,bovine enamel wear height loss was larger than the lithium disilicate specimens (P ＜ 0.05);bovine enamel wear curve exhibits a runningin period,steady wear period and severe wear period 3 stages of wear,while wear curves of lithium disilicate glass ceramics exhibit onlyrunning-in period and steady wear period 2 wear stages.Both groups had the corresponding micro-morphological features in different periods.Conclusion:Bovine enamel and lithium disilicate glass ceramics show a phase dynamic evolution law under the simulated oral environment.Bovine enamel is more susceptible to wear than lithium disilicate,suggesting that clinical attention should be paid to prevent the excessive wear of natural teeth caused by lithium disilicate glass ceramic restorations.
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Objective:To explore the method of the establishment of edentulous mandible All-on-4 implant photoelastic model with various distally tilted implants by computer-aided design(CAD).Methods:The edentulous mandible specimen was scanned by CT. Three-dimensional models of the mandible consisting of implant location were reconstructed and edited with Mimics and Geomagic Stu-dio software.Each of the four models had four implant sockets in the interforaminal area.In the first model,the bilateral distal im-plants were placed vertically.In the other models,the posterior implants were respectively inclined by 1 5°,30°and 45°distally.The four models were manufactured by RP and then the All-on-4 photoelastic models were made by traditional ways.Results:The ob-tained ethoxyline resin models featured bright surface,homogeneous structure,faintly yellowish,high optical sensibility,precision im-plants location and with no natural stress.The model offered a good experimental basis for the stress measurement.Conclusion:The method of fabricating ethoxyline resin models by CAD is reproducible,which simplifies the operating process.
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Objective To analyze the nursing effect of emotional disorder in patients with alcohol dependence.Methods From January 2009 to February 2010,81 patients in our hospital with emotional disorder of alcohol dependence were randomly divided into the observation group (41 cases)and the control group (40 cases).The control group was given routine nursing care,and the observation group was given enhanced care for emotional disorders on the basis of routine nursing care,the clinical results of two groups were compared.Results In the observation group,the re-drinking rate and readmission rate were19.5 ％ and 7.3％,significantly lower than 40.0％ and 27.5％ of the control group,the time interval of re-drinking of the observation group was significantly longer than the control group,the anxiety and depression scores were significantly better than the control group.Conclusions To give enhanced care on the basis of routine nursing care for patients with emotional disorders because of alcohol dependence has better clinical effect,it contributes to the patients′ rehabilitation.