| dc.description.abstract | Background: Closed coil spring is an additional tool in fixed orthodontic treatment, NiTi is an orthodontic alloy with shape memory and superelasticity, stainless steel is easily formed, soldered, welded and low friction between wire- bracket. Knowledge of various closed coil spring properties has been widely researched, but research on the duration are still very little. Purpose : To determine the effect and differences of duration of the stretched springs for 7, 14, 21 and 28 days compared to the closed coil spring NiTi and SS forces. Methods: Acrylic blocks measured in 7 x 5 x 1 cm, acrylic post with 25 mm distance with closed coil springs attached in between and modified T stick. Springs with treatment groups of 7, 14, 21 and 28 days were immersed in stainless steel container with artificial saliva (ph 6,75), container was put in an incubator at 37oC, then carried out and forces are measured with universal testing machine. Results: There was a significant effect between duration of strecthed springs and force of closed coil spring SS in all groups (p<0,05) and no significant effect on closed coil spring NiTi in the 7, 14 and 21 days group (p>0,05) and there was a significant effect on day 28 (p<0,05). There was a significant effect between the comparison of both (p<0,05). Conclusions: There was a significant effect on duration of the stretched closed coil spring SS and force in all group, there is an effect on closed coil spring NiTi in day 28 group | en_US |
