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Abstract
Objective: From an intuitive clinical standpoint, a more rigid archwire such as .016 should demonstrate greater efficacy for stage one tooth movement than a more flexible archwire such as .014. However, there is little to no clinical data to support this theory. This study hypothesizes that archwire dimension affects efficacy of tooth movement in Stage I orthodontic treatment due to variation in force magnitude, and this effect is independent of time due to constant force of superelastic wires. Materials and Methods: A prospective, randomized clinical trial was performed featuring 9 patients (18 dental arches) using .014 and .016 archwires. Double-blinded distribution of archwires was performed with intraoral scans obtained at 3 times points (baseline, 6 weeks, and 12 weeks). Digital measurements were performed based on Little’s Irregularity Index by a single examiner using Ortho Insight 3D. Geomagic was also used to assess Euclidean rigid motion with 6 degrees of freedom for all canines. 2-way repeated ANOVA was utilized, with the main effects being archwire dimension and time. Results: The first time interval showed greater reduction in incisor irregularity. Difference in mean translation was statistically significant between .014 and .016 in all 3 planes, as well as between the first and second time intervals for the z axis only. Finally, interaction between archwire dimension and time interval for translation was significant in the y and z planes. Conclusions: Archwire dimension does have an impact on efficacy of alignment, and alignment is, in fact, not independent of time.
