A Comparative Study of Orthodontic Coil Springs

Abstract

Several types of force delivering system are used to carry out tooth movement in orthodontics. Coil springs being one of them are used for the same thus requiring minimal operator manipulation. Aims and objectives: The purpose of this study was to determine the effect of wire diameter, lumen size and length of coil spring on the load produced as a function of displacement of SS and NiTi coil spring. Materials and methods: The study consisted of 60 samples of open and closed coil springs (30 each). Open coil springs were tested in compression and closed coil spring in tension using a Lloyd universal testing machine. The data obtained was subjected to statistical analysis using student’s t-test. Results: Mean values, standard deviation and t-value were calculated. Statistically significant difference were obtained in between the groups (p < 0.05), (p < 0.001). Discussion: The heaviest load value at 60% compression was recorded in 0.010 × 0.030 spring with 20 cm initial length due to its large wire diameter and reduced lumen size among the coil springs tested. Straight line of load deflection curve bears clinical significance due to unpredictable behavior of spring beyond a certain limit. Permanent deformation exhibited by SS coil spring is due to high stiffness is low spring fact. Conclusion: Coil linear load delivered by SS open coil springs on compression changes the original length from 33 to 50% which depends on wire diameter and lumen size of coil spring.