Avaliação de atrito estático e dinâmico em dois sistemas de bráquetes: autoligado e convencional

Resumo (EN)

Introduction:The aim of this in vitro study was to evaluate the static and dynamic friction of self ligating and conventional orthodontic brackets. Methods: Four types of self ligating brackets were evaluated (SLI Morelli®; EASY CLIP Aditek®;PORTIA Abzil 3M R® e ORTHOCLIP Orthometric®). The dynamic and static frictional forces were compared with those of a group of conventional orthodontic brackets (ROTH MAX Morelli®) associated with traditional elastic ligatures (Morelli®), which served as control group. For all the brands, brackets for teeth 21 to 25 with slot 0.022” and Roth prescription were used. The following archwires were used for analysis: Morelli® Brand stainless steel and nickel titanium wires, sizes: 0.014”/ 0.016”/ 0.019x0.025” . For the friction test performed in an EMIC DL 500 Universal test machine, the sliding and frictional force readout was taken at a speed of 10mm/min, with the universal test machine calibrated at a force of 0 and run of 55mm of wire in each test. Each test specimen consisting of bracket/wire was submitted to five consecutive tests in order to increase the reliability of the results attained. Results: The non parametric KruskalWallis test showed statistical difference between the groups, and the Student Newman – Keul test was applied for multiple comparisons ( p≤0.05). Conclusion: All the brackets presented higher static and dynamic frictional force when the wire size of was increased.