The average force, hysteresis and unload/peak ratio during repeated extension of Memory chain (American Orthodontics, Sheboygan, MI, USA) and the percentage of the residual force to the force at the first extension
| Cycle | 12.5 mm peak | 11.5 mm load | 1 mm unload | Hysteresis | 1-mm-unload/peak ratio |
|---|---|---|---|---|---|
| 1st cycle | 366.1±5.3a | 353.3±5.3a | 298.8±4.5a | 54.5±1.6a | 81.6±0.35%d |
| 100% | 100% | 100% | 100% | ||
| 2nd cycle | 352.8±5.1b | 318.7±4.9b | 291.5±4.4b | 27.2±1.2b | 82.6±0.25%c |
| 96.4±0.37% | 90.2±0.38% | 97.6±0.45% | 49.9±2.2% | ||
| 3rd cycle | 346.3±5.1c | 309.6±4.9c | 287.8±4.6c | 21.8±1.0c | 83.2±0.35%b |
| 94.6±0.44% | 87.6±0.45% | 96.3±0.36% | 39.8±2.3% | ||
| 4th cycle | 341.2±4.8d | 304.4±4.8d | 284.9±4.5d | 19.5±1.4d | 83.6±0.36%a |
| 93.2±0.45% | 86.2±0.42% | 95.3±0.51% | 36.0±2.7% | ||
| 5th cycle | 338.0±4.8e | 300.6±4.5e | 282.5±4.3e | 18.2±1.3e | 83.7±0.39%a |
| 92.3±0.40% | 85.1±0.44% | 94.5±0.59% | 33.6±2.8% |
Values are presented as mean±standard deviation. Unit: gram-force (gf).
a,b,c,d,eDifferent letters indicate significant statistical differences among cycles (