关键词: 弹力链, 力值衰减, 热循环

Abstract:

Objective    To test the influence of the type of filament and the number of loops on force degradation of elastomeric chains under the condition of thermal cycle. Methods    The elastomeric chains tested in this study included 3 kinds of filament types：close，medium and long. Each type of the elastomeric chains were all cutted into four，five and six loops. And various chains were stretched to produce the initial force of 250 g. Then arrange the experiment groups by the orthogonal design，and the stretched length of different groups of chains were maintained respectively in artificial saliva environment of 37℃ and thermocycled between 5℃ and 55℃ for 3 time a day. The remaining force of the elastomeric chains were recorded at different moments in 4 weeks. Then calculate the percentage of remaining force. Results            The force of elastomeric chain gradually decayed over time，under the condition of thermal cycle. The force degradation was sharp in the first 4 hours. The force degradation was the fastest within the end of 24 hours. Force decay percentage increased slightly between 24 hours to 28 days. Differences among different connection types as well as loops on force degradation at each time point were statistically significant. When given the same stretched force，the strerched length of close， medium， large filament types and 4，5，6 loops were increased in sequence. Conclusion    The force of elastomeric chain fastest decayed within the initial 4 hours and stabilized after 24 hours under the condition of thermal cycle； while the initial force is the same premise，the longer the connector body，the fewer number of turns，the greater the force degradation of elastomeric chain.

Key words: elastomeric chain, force degradation, thermal cycle