Calcium hydroxide（CH） is applied to improve disinfection of root canals in most root canal retreatment. This study aimed to analyze the CH removal efficacy using 7 different root preparing files（K file, pre-curved ...Calcium hydroxide（CH） is applied to improve disinfection of root canals in most root canal retreatment. This study aimed to analyze the CH removal efficacy using 7 different root preparing files（K file, pre-curved K file, EndoActivator, Ultrasonic file, pre-curved ultrasonic file, F file and needle irrigation alone） with apical transportation. Standardized models of curved canal with such apical transportation or not were set up before applying CH to root canal for 7 days. Seven techniques described above were used for its removal. Then the roots were disassembled and digital photos were taken. The ratio of residual CH in the overall canal surface was calculated using the image analyzer image pro plus 6.0. The data were analyzed using one-way ANOVA with post hoc Tukey test. Results revealed that CH was effectively removed（P〈0.05） by using all 6 mechanical methods except irrigation alone. In curved root canals with apical transportation, EndoActivator, pre-curved ultrasonic file and F file were found to be more effective in removing CH than the other four file（P〈0.001）, while there was no significant difference among EndoActivator, pre-curved ultrasonic file and F file groups（P〉0.05）. The percentage of residual CH in the canal with apical transportation was higher than that in the canal without apical transportation（P〈0.05）. In conclusion, CH can be hardly removed completely. Canal with apical transportation will result in insufficient CH removal. EndoActivator, pre-curved ultrasonic file and F file are more effective in the curved root canal with apical transportation.展开更多
The expansion of the Panama Canal will have a profound impact on the container shipping route network, port layout and ship structure, and promote the evolution of the global shipping pattern. However, most of the res...The expansion of the Panama Canal will have a profound impact on the container shipping route network, port layout and ship structure, and promote the evolution of the global shipping pattern. However, most of the research on the expansion of the Panama Canal currently stays before its real expansion, and the quantitative analysis is less and the result is not accurate, because previous research used data that expanded before. Based on the actual data after the expansion of the Panama Canal, this paper uses the dual-target route distribution model to analyze the expansion of the Panama Canal. The changes in the liner shipping plan that have a greater impact on the shipping industry will provide the relevant theoretical basis for the relevant entities. The results show that after the expansion of the Panama Canal, the largest 15,000 TEU container ship is currently deployed on the route through the Panama Canal. 6500 TEU ship type is also deployed on the route through the Panama Canal. The 8500 TEU, 10,500 TEU, and 12,500 TEU ship types are mainly deployed through the Suez Canal. On the route, such a distribution plan can maximize the benefits for the shipping company.展开更多
基金supported by the National Natural Science Foundation of China(No.81200781)
文摘Calcium hydroxide（CH） is applied to improve disinfection of root canals in most root canal retreatment. This study aimed to analyze the CH removal efficacy using 7 different root preparing files（K file, pre-curved K file, EndoActivator, Ultrasonic file, pre-curved ultrasonic file, F file and needle irrigation alone） with apical transportation. Standardized models of curved canal with such apical transportation or not were set up before applying CH to root canal for 7 days. Seven techniques described above were used for its removal. Then the roots were disassembled and digital photos were taken. The ratio of residual CH in the overall canal surface was calculated using the image analyzer image pro plus 6.0. The data were analyzed using one-way ANOVA with post hoc Tukey test. Results revealed that CH was effectively removed（P〈0.05） by using all 6 mechanical methods except irrigation alone. In curved root canals with apical transportation, EndoActivator, pre-curved ultrasonic file and F file were found to be more effective in removing CH than the other four file（P〈0.001）, while there was no significant difference among EndoActivator, pre-curved ultrasonic file and F file groups（P〉0.05）. The percentage of residual CH in the canal with apical transportation was higher than that in the canal without apical transportation（P〈0.05）. In conclusion, CH can be hardly removed completely. Canal with apical transportation will result in insufficient CH removal. EndoActivator, pre-curved ultrasonic file and F file are more effective in the curved root canal with apical transportation.
文摘The expansion of the Panama Canal will have a profound impact on the container shipping route network, port layout and ship structure, and promote the evolution of the global shipping pattern. However, most of the research on the expansion of the Panama Canal currently stays before its real expansion, and the quantitative analysis is less and the result is not accurate, because previous research used data that expanded before. Based on the actual data after the expansion of the Panama Canal, this paper uses the dual-target route distribution model to analyze the expansion of the Panama Canal. The changes in the liner shipping plan that have a greater impact on the shipping industry will provide the relevant theoretical basis for the relevant entities. The results show that after the expansion of the Panama Canal, the largest 15,000 TEU container ship is currently deployed on the route through the Panama Canal. 6500 TEU ship type is also deployed on the route through the Panama Canal. The 8500 TEU, 10,500 TEU, and 12,500 TEU ship types are mainly deployed through the Suez Canal. On the route, such a distribution plan can maximize the benefits for the shipping company.
