The Force Decrease Differences Between ISO-Standardized and Non-ISO-Standardized Long and Short Power Chain

Power chain is one of auxiliaries used in orthodontic treatment primarily for teeth retraction. The force generated by power chain decays over time and about 13 %-75 % of the initial force is lost in the first 24 hours. The level of force decrease depends on several conditions, mostly the type, quality, and size of the power chain. In this study, 4 rolls of power chain (ISO-standardized long power chain, ISO-standardized short power chain, non-ISO-standardized long power chain, and non-ISO-standardized short power chain) were cut to a specific length.4 multiplex boards with 10 lines of pins with 2 pins facing each other within10mm distance were used to stretch the chain. The boards were then incubated in artificial saliva at 37oC for 21 days. The initial force was recorded at day 0 and the force decrease was recorded 3 times at day 1, 14 and 21. The data were analyzed by ANOVA test and compared using the ANOVA. There was a statistically significant difference between specimens groups regarding the force decrease. All groups showed force decrease over time, regardless of their length in both ISO-standardized and non-ISO-standardized power chain. On the first day the force loss of 35-40 % was observed and up to 55 % after 21 days of activation.