|
KMID : 0361919910210020433
|
|
Korean Journal of Orthodontics
1991 Volume.21 No. 2 p.433 ~ p.446
|
|
|
RELAXATION OF ORTHODONTIC ELSASTICS, ELASTOMERIC MODULES AND CHAINS
|
|
|
|
|
Abstract
|
|
|
The present study was performed to evaluate the relaxation patterns of rubber elastics, elastomeric modules and chains stored in the water bath.
Initial loading profiles were established for extension of 100%, 200% of their original length for elastomeric chains and of 21, 28, 35, 42, 49mm for rubber elastics and elastomeric modules. The tests were performed on materials stored in distilled water at 37°C and extraoral elastics stored in dry state at room temperature, at 0 hour, 1 hour, 6 hours, I day, 1 week, 2 weeks, 3 weeks, and 4 weeks, respectively.
The following results were drawn:
1. The relaxation of rubber elastics manifested -no correlation with increments of the extension distances, but showed correlation with time lapse. Remaining forces of rubber elastics came out 84.64-98.52% after 1 day, 70.92-89.31% after 3 weeks of period.
2. The relaxation of elastomers manifested no correlation with increments of the extension > distances, however represented considerable relaxation with time lapse as rapid relaxation after 1 hour and then gradual relaxations with time lapse. Modules relaxed much more than chains..
60.58-67.05% of remaining forces for chains and 37.77-65.17% for modules after 1 hour were turned out, and 51.48-62.22% for chains and 8.04-25.15% for modules after 3 weeks as well.
3. Permanent deformation rates of rubber elastics could not be measured with present investigation, but elastomers underwent severe deformations.
4. 3-9% of permanent deformations for chains, 3-10% for modules at 0 hour were turned out, and 25-30% for chains, 96-145% for modules after 3 weeks as well.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
 
|
|
|
Listed journal information
|
|
  
|
|