In case of monor crowding, including one or two teeth. open-coil and vertical loop were commonly used. But, in clinical view point. they have some disadvantages:
1. Tipping and rotation of adjacent teeth.
2. difficult to reactivate.
3. prolonged wear cause arch bulging.
4. relapse may decrease the gained space during arch leveling, and 4)needs leveling time to correct the tipped or rotated adjacent teeth, therefore it takes long treatment times. Named Twin Helical Loop was modified from vertical loop to improve
disadvantages from open-coil and vertical loop, designed continuing two helix by horizontal by pass bar, included ideal arch.
@ES Treatment of Twin Helical Loop need 3 steps:
@EN 1. Sapce regaining stage.
2. relocation stage, and
3. leveling stage.
@ES Results and conclusion : By application of Twin Helical Loop, the results were as followed:
@EN 1. in treatment time, compared with open-coil. Twin Helical Loop was better.
2. in case of Twin Helical Loop, tipping or rotation of adjacent teeth was hardly observed during treatment and.
3. it was concluded that little side-effect of Twin helical Loop can lead to obtain the efficiency of t
treatment.
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