Accuracy of Force Delivery of Nickel Titanium, Stainless Steel, and Cobalt Chromium Nickel Coil Springs.
Bednarz, Alana.
2015
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Abstract: ABSTRACT Aim & Hypothesis: Aims of this study were to compare the in vitro force levels of various NiTi springs to each other at 3mm, 6mm and 9mm extensions and to compare the in vitro force delivery of different types of compression coil springs ( NiTi, stainless steel, and Elgiloy) at 3, 6, and maximum compression. It was hypothesized that NiTi constant springs' force levels do not ... read moreremain at a constant force over full activation as described by manufacturers. NiTi springs force levels do not decay continuously over time like those of stainless steel and cobalt chromium nickel (Elgiloy) springs. Materials & Methods: This study was an in vitro study designed to compare NiTi, stainless steel, and cobalt chromium nickel (Elgiloy) coil springs from three different companies (GAC Dentsply, RMO, and G&H). Closed and open coil springs were tested using Tinius Olsen Tension Compression Tester. Each coil type was tested ten times at 9mm extension/maximum compression, 6mm extension/compression, and 3mm extension/compression. All statistical analysis was conducted using SPSS (version 23.0) with One way ANOVA, Repeated measures ANOVA, Paired t test, and Independent samples t test. Mann-Whitney U test and Kruskal-Wallis test were used in instances where parametric assumptions were violated. Results: Closed Coils: Each coil type, regardless if a variable or constant force coil, there is a significant decrease in force delivery as the coils recoiled. There was also a difference noted in force delivery at the 3mm and 6mm recoil when the coils are initially stretched to 9mm in comparison to an initial 6 and 3mm extension. Open Coils: Differences were noted in force delivery at the 3mm and 6mm decompression after maximum compression in comparison to an initial 6 and 3mm compression when comparing the different coil materials. A large difference between maximum compression and subsequent decompression marks regardless if the material is NiTi, stainless steel, or Elgiloy. Conclusions: Closed Coils: Variations were shown in each extension for both constant and variable force NiTi coils. Pre stretching the coil does make a difference in force delivery as differences were noted in the force of those extended to 9mm versus 6mm and 3mm. Open Coils: At all different compression levels differences in forces were found between all the material types of coils. NiTi delivered the lowest force levels in comparison Elgiloy and stainless steel. Pre compressing makes a difference in the force delivery of the coils during decompression.
Thesis (M.S.)--Tufts University, 2015.
Submitted to the Dept. of Orthodontics.
Advisor: Georgios Kanavakis.
Committee: Carroll Ann Trotman, Matthew Finkelman, Moonyoung Lee, and Leon Laub.
Keyword: Dentistry.read less - ID:
- 3484zv428
- Component ID:
- tufts:20259
- To Cite:
- TARC Citation Guide EndNote
