Date of Award
Master of Science (MS)
David W. Berzins
Thomas G. Bradley
Introduction: The translucent optical property of fiber-reinforced composite wires meets the esthetic demand of orthodontic patients; however, studies need to be conducted to determine if they also have the desired mechanical properties for active orthodontic treatment. The goal of this research was to study the effect of water storage on the mechanical properties of fiber-reinforced composite archwires and compare it to conventional nickel-titanium (NiTi) and stainless steel (SS), and beta-titanium (TMA) archwires. Materials and Methods: Align A, B, C and TorQ A, B from BioMers Products, 0.014", 0.016", 0.018", 0.019" x 0.025" Nitinol Classic (3M Unitek), 0.016" SS, and 0.019 x 0.025 TMA archwires were tested in this study (n=10/type/size/condition). A 20 mm segment was cut from each end of the archwire with one then stored in distilled water at 37°C for 30 days while the other was stored dry. The segments were tested at 37±2°C using 3-point bending to a maximum deflection of 3.1 mm with force monitored during loading (activation)/unloading (deactivation). ANOVA and paired t-tests were used for statistical analysis.
Results: In terms of stiffness and force delivery during activation, in general 0.019" x 0.025" TMA > TorQ B > TorQ A > 0.019" x 0.025" NiTi > 0.016" SS > Align C > 0.018" NiTi > Align B > 0.016" NiTi > Align A > 0.014" NiTi. Water exposure was detrimental to the larger translucent wires (Align B and C) as they were more likely to crack/craze during bending, resulting in decreased amounts of force applied at a given deflection. All TorQ A and B wire segments cracked during the test; the stored in water groups had significantly greater decrease in force level delivery. Align A and the alloy wires were not significantly affected by water storage. Overall, the alloy wires possessed vastly more consistent force values compared to the composite wires. Conclusions: Although the translucent archwires from BioMers present a more esthetic option for patients, their mechanical response is less reliable than alloy wires, possibly compromising treatment efficiency.
Available for download on Saturday, May 25, 2013