Resistance to sliding of orthodontic archwires under increasing applied moments

Abstract

Background: Orthodontic treatment with fixed appliances involves sliding of brackets along archwires. These movements involve friction, which causes resistance to sliding. In addition, moments cause teeth to tip until binding occurs between the bracket and archwire. The manufacturer of a new TiMolium®Titanium archwire claims material properties superior to β-Titanium, potentially leading to reduced resistance to sliding. Objective: To compare TiMolium archwires with β-Titanium and stainless steel archwires as the current gold standard for sliding mechanics under application of an increasing moment. Materials and methods: A total of 120 stainless steel (Smartclip, 3M, Monrovia, CA) and ceramic self-ligating 0.022″-slot brackets (Clarity SL, 3M) were divided into six equal-sized groups. Resistance to sliding was tested with 0.019″ × 0.025″ TiMolium (TP Orthodontics, La Porte, IN), β-Titanium (3M), and stainless steel (3M) archwires using a custom-designed apparatus to simulate sliding mechanics and application of moments of 1000, 2000, and 3000 g-mm. Results: Using stainless steel brackets, the TiMolium archwires had significantly higher resistance to sliding than stainless steel archwires at all moments tested while there was no difference between TiMolium and β-Titanium. Using ceramic brackets, the resistance to sliding with TiMolium archwires was no different than with stainless steel archwires. Both TiMolium and stainless steel archwires showed significantly lower resistance to sliding than β-Titanium. Conclusion: TiMolium archwires have resistance to sliding intermediary to stainless steel and β-Titanium archwires when clinically relevant moments are applied. Used with the stainless steel brackets, they behave like β-Titanium, whereas used with the ceramic brackets, they behave more like stainless steel.