Date of Award
Thesis - Restricted
Master of Science (MS)
The purposes of the study are to determine whether clinical use changes the microstructure of a Ni-Ti orthodontic wire and to assess the validity of manufacturers' claims. X-ray diffraction and Vickers hardness data have been shown to corroborate the microstructural findings. Therefore, these techniques were used to examine a Ni-Ti wire for any possible structural change after a period of clinical use. Sixteen wires of 0.016 inch diameter Nitinol Classic were tested in the "as-received" conditions and then after four to six weeks of clinical use. X-ray diffraction analyses showed a 9.8% decrease in the peak height for the  austenite reflection of the after use wires compared to the before use wires after four to six weeks of clinical use (significant at p < 0.02). In addition, there was a 6% decrease in Vickers hardness in the after use wires compared to the before use wires after four to six weeks of clinical use (significant at p< 0.001). The decrease in peak height for the  austenite reflection and the decrease in Vickers hardness after four to six weeks of clinical use indicate some austenite may be irreversibly transformed to martensite during clinical use. The results of this study demonstrate that the structural properties of these wires were altered after clinical use.
Santos-Rangsuebsin, Sarah Lynn, "X-Ray Diffraction and Vickers Hardness Analyses of Nickel-Titanium Orthodontic Wires Before and After Clinical Use" (2002). Master's Theses (1922-2009) Access restricted to Marquette Campus. 5289.