Nanoindentation of orthodontic archwires: The effect of decontamination and clinical use on hardness, elastic modulus and surface roughness

Abstract Objectives The purpose of this research was to investigate the effects of decontamination and clinical exposure on the elastic moduli, hardness and surface roughness of two frequently used orthodontic archwires, namely 0.020 in. × 0.020 in. heat activated (martensitic active) nickel titaniu...

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Bibliographic Details
Published in:Dental materials 2009-08, Vol.25 (8), p.1039-1043
Main Authors: Alcock, Joseph P, Barbour, Michele E, Sandy, Jonathan R, Ireland, Anthony J
Format: Article
Language:English
Subjects:
Advanced Basic Science
Archwires
Atomic force microscopy
Decontamination
Dental Alloys
Dental Stress Analysis - methods
Dentistry
Elastic Modulus
Equipment Reuse
Hardness
Humans
Nanoindentation
Nanotechnology
Nickel
Nickel titanium
Orthodontic Wires
Orthodontics
Pilot Projects
Prospective Studies
Stainless Steel
Surface Properties
Titanium
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Summary:Abstract Objectives The purpose of this research was to investigate the effects of decontamination and clinical exposure on the elastic moduli, hardness and surface roughness of two frequently used orthodontic archwires, namely 0.020 in. × 0.020 in. heat activated (martensitic active) nickel titanium archwires and 0.019 in. × 0.025 in. austenitic stainless steel archwires. Method This study was a prospective clinical trial in which 20 consecutive patients requiring an archwire change as part of their course of orthodontic fixed appliance therapy, had either a nickel titanium or stainless steel archwire fitted as deemed clinically necessary. The effect of clinical use was determined by comparing distal end cuts of the “as received” archwires before and after decontamination, with the same retrieved archwires following clinical use and decontamination. Hardness, elastic modulus and surface roughness were determined using an atomic force microscope (AFM) coupled with a nanoindenter. Results The results showed that the decontamination regimen and clinical use had no statistically significant effect on the nickel titanium archwires, but did have a statistically significant effect on the steel archwires. Decontamination of the steel wires significantly increased the observed surface hardness ( p = 0.01) and reduced the surface roughness ( p = 0.02). Clinical use demonstrated a statistically significant increase in the observed elastic modulus ( p < 0.001) and a decrease in surface roughness ( p = 0.001). Significance At present it is difficult to predict the clinical significance of these statistically significant changes in archwire properties on orthodontic tooth movement.
ISSN:0109-5641
1879-0097
DOI:10.1016/j.dental.2009.03.003