Subject(s)
Neoplasms/therapy , Animals , Combined Modality Therapy , Humans , Neoplasms/physiopathology , Signal Transduction , VasoconstrictionABSTRACT
Sentalloy springs (GAC, Central Islip, N.Y.) of the open and closed type were investigated with a special designed device. The closed coil springs were subjected to a tensile and the open coil springs to a compression test. After a first measurement, the springs were activated for a period of 4 weeks and then reinvestigated with the same procedure. It could be shown distinctly that, with the different coil springs, the force delivery given by the producer could be achieved only within certain limits. To remain in the martensitic plateau, changed activation ranges, and for the Sentalloy coil springs white and red of the open and closed type, also changed force deliveries had to be taken into account. There was a distinct decrease in force delivery between the first and second measurement. After considering the loading curves of all the Sentalloy coil springs and choosing the right activation range respective to the force delivery, it was found that the coil springs deliver a superior clinical behavior and open new treatment possibilities.
Subject(s)
Dental Alloys , Dental Stress Analysis , Nickel , Orthodontic Appliances , Titanium , Cuspid , Elasticity , Humans , Materials Testing , Statistics, Nonparametric , Tooth Movement Techniques/instrumentation , Tooth, Impacted/therapyABSTRACT
The paper describes devices which enable the orthodontist (oral surgeon) to accurately determine the forces produced by orthodontic wire or spring constructions. An apparatus was developed with which the force applied by bent wires--various materials and bending methods--could be assessed. This device uses strain gauges arranged in the form of a semi-bridge as sensors. Measurements showed that the smallest application of force was achieved with braided stainless steel wires. With respect to the consistency of the force applied, nickel-titanium alloys (so-called Japanese Ni-Ti) proved the best material for wires bent with electric current. A second device was constructed which permits the evaluation of the compression and tensile forces applied by springs as a function of movement. Here, too, strain gauges were used as sensors. The freely adjustable range can be determined using a digital distance meter with an accuracy of 0.1 mm. Measurement of the elastic behaviour of these spring configurations revealed that in comparison with stainless steel, nickel-titanium alloys were much more consistent in terms of force applied. Using these devices, the orthodontist can fit calibrated configurations, thus avoiding unsuitable forces.
