Comparison of frictional resistance between self-ligating and conventional brackets tied with elastomeric and metal ligature in orthodontic archwires

Vanessa Vieira Leite,Alcides Gonini Júnior,Renato Rodrigues De Almeida,Marcio Rodrigues De Almeida,Sandra Kiss Moura,Murilo Baena Lopes

doi:10.1590/2176-9451.19.3.114-119.oar

Abstract

ObjectiveTo compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire.Material and MethodsAbzil Kirium Capelozza (Pattern I) and Easy Clip (Roth prescription) incisor brackets were used. An elastomeric ligature or a ligating wire 0.10-in was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were assessed: 0.016-in NiTi wire, 0.016 x 0.021-in NiTi wire and 0.019 x 0.025-in steel wire. Ten observations were carried out for each bracket-archwire angulation combination. Brackets were mounted in a special appliance, positioned at 90 degrees in relation to the wire and tested in two angulations. Frictional test was performed in a Universal Testing Machine at 5 mm/min and 10 mm of displacement. The means (MPa) were submitted to ANOVA and Tukey's test set at 5% of significance. The surfaces of wires and brackets were observed at SEM.ResultsSteel-tied brackets (16.48 ± 8.31) showed higher means of frictional resistance than elastomeric-tied brackets (4.29 ± 2.16 ) and self-ligating brackets (1.66 ± 1.57) (P < 0.05), which also differed from each other (P < 0.05). As for the type of wire, 0.019 x 0.025-in steel wire (5.67 ± 3.97) showed lower means (P < 0.05) than 0.16-in NiTi wire (8.26 ± 10.92) and 0.016 x 0.021-in NiTi wire (8.51 ± 7.95), which did not differ from each other (P > 0.05). No statistical differences (P > 0.05) were found between zero (7.76 ± 8.46) and five-degree (7.19 ± 7.93) angulations.ConclusionsFriction was influenced not only by the type of bracket, but also by the ligating systems. Different morphological aspects were observed for the brackets and wires studied

Highlights

Orthodontic sliding mechanics is one of the most common methods of translating a tooth in a mesiodistal way, i.e., with canine or anterior retraction
When the groups were analyzed according to the type of bracket, steel-tied brackets (16.48 ± 8.31) showed higher means, followed by elastomerictied brackets (4.29 ± 2.16) and self-ligating brackets (1.66 ± 1.57) All groups showed statistical differences (P < 0.05) when compared to each other (Table 1)
When the type of wire was analyzed, 0.019 x 0.025-in stainless steel wire (5.67 ± 3.97) showed lower means, with statistical difference (P < 0.05) in comparison to 0.16-in NiTi wire (8.26±10.92) and 0.016 x 0.021-in NiTi wire (8.51 ± 7.95), which did not differ from each other (Table 2)

Summary

Introduction

Orthodontic sliding mechanics is one of the most common methods of translating a tooth in a mesiodistal way, i.e., with canine or anterior retraction. Friction is only one part which resistance to movement consists of when a bracket slides along an archwire.[4,9] It is determined by the type and size of the archwire, type of bracket, angulation between the archwire and the bracket slot and the method of ligation Since this force operates in the opposite direction of the mobile body, it is important that it be eliminated or minimized when orthodontic tooth movement is being planned,[2,8,27] otherwise it may delay tooth movement, increase anchorage requirement, or both.[6,21]

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Conclusion