Analysis of Intrusion Forces in Stainless Steel and Nickel-Titanium Orthodontic Archwires: An Experimental Study

Orthodontics involves alignment of improperly positioned teeth mostly with fixed appliances. Round archwires are commonly used for intrusion of anterior teeth. The aim of this study was to measure the magnitude of force required to deflect the archwire for 2 mm between central and lateral incisors. To mimic the real oral domain, an experimental set-up with maxilla and mandible with metallic teeth was constructed. Orthodontic brackets (0.018 x 0.025) were bonded on the metal tooth and 0.016 Stainless steel (SS) and Nickel Titanium (NiTi) archwires were used with SS ligature. The archwire is deflected for 2 mm and a three point bending test was performed to measure the force magnitude using a six-axis spine tester. The forces from NiTi and SS archwires were 10.3 N and 11.4 N respectively in the maxilla, and 13.2 N and 15.3 N respectively in the mandible. As the deflection increases the loading forces also increase and is higher in SS than NiTi. Clinicians can thus select their wire deflection for the amount of force needed for intrusion planning. © (2024) Society for Biomaterials & Artificial Organs #20004424.