The average force, hysteresis and unload/peak ratio during repeated extension of Generation II power chain (Ormco, Glendora, CA, 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 | 378.2±11.3a | 365.1±10.6a | 309.6±8.5a | 55.6±2.5a | 81.9±0.41%d |
| 100% | 100% | 100% | 100% | ||
| 2nd cycle | 365.5±10.9b | 332.5±9.5b | 303.2±8.4b | 29.3±1.5b | 83.0±0.42%c |
| 96.6±0.33% | 91.1±0.46% | 97.9±0.45% | 52.8±2.2% | ||
| 3rd cycle | 358.6±10.1c | 323.1±9.3c | 299.8±8.4c | 23.6±1.5c | 83.5±0.38%b |
| 94.8±0.42% | 88.5±0.46% | 96.7±0.45% | 42.5±2.1% | ||
| 4th cycle | 354.3±10.5d | 318.1±9.3d | 297.0±8.5d | 21.2±1.4d | 83.8±0.36%a |
| 93.7±0.37% | 87.1±0.40% | 95.9±0.48% | 38.1±1.8% | ||
| 5th cycle | 351.2±10.4e | 314.6±9.0e | 295.1±8.7e | 19.5±1.3e | 84.0±0.35%a |
| 92.9±0.42% | 86.2±0.45% | 95.3±0.56% | 35.1±2.7% |
Values are presented as mean±standard deviation. Unit: gram-force (gf).
a,b,c,d,eDifferent letters indicate significant statistical differences among cycles (