Influence of Mastication on Orthodontic Wire Sliding in Nickel-Titanium Brackets with Superelastic Wings

(1) Background: Orthodontic tooth movement (OTM) during sliding mechanics is influenced by a multitude of interactions. Studies suggest that vibration induced by mastication or usage of electric tooth brushes might impact resistance to sliding (RS) in conventional brackets. In superelastic brackets, archwire sliding might also be altered due to deformation of the bracket wings during mastication. Therefore, the aim of this study was to investigate how the superelastic properties of Nickel-Titanium (NiTi) brackets affect archwire sliding during mastication. (2) Methods: Orthodontic superelastic NiTi archwires with diameters of 0.014" and 0.016" were ligated into four superelastic NiTi brackets. One bracket was positioned with a vertical offset of 1 mm to simulate clinical vertical leveling. A weight force was applied to axially preload the archwire. The occlusal and axial forces affecting the movement of the archwires through the bracket were measured. (3) Results: Low chewing forces caused a measurable axial movement of the 0.014" wire. Increased chewing forces resulted in higher axial movements. The archwire diameter had an impact: 0.014" NiTi required lower masticatory forces to initiate wire motion as compared to the 0.016" NiTi. (4) Conclusions: The superelastic NiTi brackets examined showed that under simulated continuous dynamic masticatory loading, obstacles such as friction or binding could be overcome.