The Angle orthodontist · 2009
Holographic analysis of the initial canine displacement produced by four different retraction springs.
Сравнительное исследованиеСтатьяНазвание и аннотация: Перевод в очереди
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Kumar Y Mahesh, Ravindran N S, Balasubramaniam M R
Аннотация
OBJECTIVES: To estimate and compare the magnitude and direction of initial displacement of the canine produced by four different canine retraction springs.
MATERIALS AND METHODS: A freshly macerated mandible was used as an experimental model. First premolars were extracted, and strap-up was done with a 0.018 inch Roth Preadjusted Edgewise System (3M Unitek, Monrovia, Calif). The canine was subjected to loads of 4 oz, 5 oz, and 6 oz, each applied by four different canine retraction springs, that is, closed coil spring, open coil spring, PG spring, and T-loop retraction spring. The magnitude and direction of the initial displacement of the canine were studied by means of double-exposure interferometry.
RESULTS: The PG spring produced the highest initial displacement for a given force among the force systems used, followed by open coil, closed coil, and T-loop. Maximum tipping was observed with the open coil spring, followed by the PG spring, the closed coil spring, and the T-spring.
CONCLUSION: The T-loop may be preferred whenever minimal tipping is performed. The PG spring may be preferred over other springs whenever a higher magnitude of displacement is desired. Closed coil springs may be preferred whenever a reasonable magnitude of displacement is required and reasonable tipping is allowed.
MATERIALS AND METHODS: A freshly macerated mandible was used as an experimental model. First premolars were extracted, and strap-up was done with a 0.018 inch Roth Preadjusted Edgewise System (3M Unitek, Monrovia, Calif). The canine was subjected to loads of 4 oz, 5 oz, and 6 oz, each applied by four different canine retraction springs, that is, closed coil spring, open coil spring, PG spring, and T-loop retraction spring. The magnitude and direction of the initial displacement of the canine were studied by means of double-exposure interferometry.
RESULTS: The PG spring produced the highest initial displacement for a given force among the force systems used, followed by open coil, closed coil, and T-loop. Maximum tipping was observed with the open coil spring, followed by the PG spring, the closed coil spring, and the T-spring.
CONCLUSION: The T-loop may be preferred whenever minimal tipping is performed. The PG spring may be preferred over other springs whenever a higher magnitude of displacement is desired. Closed coil springs may be preferred whenever a reasonable magnitude of displacement is required and reasonable tipping is allowed.