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目的通过体外实验在热循环条件下研究连接体类型以及圈数对于弹力链力值衰减的影响。方法本研究于2013年在中国医科大学附属口腔医院中心实验室进行。将4、5、6个圈数的短、中、长距型弹力链按照正交实验设计进行组合,拉伸250 g(1 g=0.0098 N)初始力值,置于37℃人工唾液环境下,每日3次15~55℃热循环;利用电子推拉力仪,测量各组弹力链在加力4、24 h以及7、14、21、28 d的剩余力值大小及各测量时间点的力值衰减百分比。结果在15~55℃热循环条件下,弹力链力值随加力时间逐渐衰减,在最初的4 h内力值衰减急剧,24 h末内衰减最快,24 h至28 d之间各时间点力值衰减百分比增幅不大;各时间点不同连接体类型及圈数对弹力链力值衰减影响的差异均有统计学意义(P<0.01);短、中、长距型弹力链力值衰减百分比依次增大,4、5、6个圈数弹力链力值衰减百分比依次减小。结论在15~55℃热循环条件下,弹力链力值在4 h内衰减最快,24 h后衰减趋于稳定;在初始力相同的前提下,连接体越长,圈数越少,弹力链力值衰减越大。
OBJECTIVE: To study the effect of the type of linker and the number of turns on the strength decay of elastic chain in vitro under thermal cycling conditions. Methods The study was conducted in 2013 at the Central Laboratory of Stomatology Hospital, China Medical University. The short, medium and long-distance elastic chains of 4, 5 and 6 turns were combined according to the orthogonal experimental design. The initial force of 250 g (1 g = 0.0098 N) was stretched and placed in a 37 ° C artificial saliva environment , Three times a day 15 ~ 55 ℃ thermal cycle; the use of electronic push-pull instrument to measure the elastic chain in each group at 4,24 h and 7,14,21,28 d of residual force value size and the measurement time points Percentage decay of force. Results Under the condition of 15 ~ 55 ℃ thermal cycling, the force value of elastic chain gradually decayed with the application of force, the force value decayed sharply in the first 4 h, and the decay was the fastest in the end of 24 h. At each time point between 24 h and 28 d, The percentage of decay of force value did not increase much. The difference of the effect of different types of connectors and the number of turns on the decay of elastic chain at all time points was statistically significant (P <0.01) The percentage increases in turn, 4, 5 and 6 turns reduce the percentage of elastic chain strength reduction in turn. Conclusion Under the condition of 15 ~ 55 ℃ thermal cycling, the force value of elastic chain decays fastest within 4 h and decays after 24 h. Under the same initial force, the longer the connecting body, the smaller the number of turns, Chain strength decay greater.