Analysis of Different Positions of Fiber-Reinforced Composite Retainers versus Multistrand Wire Retainers Using the Finite Element Method.

Arezoo Jahanbin,Hooman Shafaee,Farzin Heravi,Mostafa Abtahi,Mohsen Hoseini

doi:10.1155/2014/581029

Abstract

Background. The aim of this study was to evaluate root displacement of the lower incisors fixed with FRC in different positions versus FSW retainers using the finite element method. Materials and Methods. 3D finite element models were designed for a mandibular anterior segment: Model 1: flexible spiral wire bonded to the lingual teeth surfaces, Model 2: FRC bonded to the upper third of lingual teeth surfaces, and Model 3: FRC bonded to the middle third. FE analysis was performed for three models and then tooth displacements were evaluated. Results. In contrast to lateral incisors and canines, the FSW retainer caused the central teeth to move more than the teeth bonded with FRC in both loadings. Comparison between Models 2 and 3 (in vertical loading) showed that FRC retainers that bonded at the upper third of lingual teeth surfaces made central and canine teeth move less than FRC retainers bonded at the middle third; however, for lateral teeth it was the opposite. Conclusion. FRC retainers bonded at the upper third of lingual teeth surfaces make central and canine teeth move less than FRC retainers bonded at the middle third in vertical loading; however, for lateral teeth it was the opposite.

Highlights

Contemporary retaining strategies in orthodontics basically include removable and fixed retainers
Two different forms of fixed retainers are widely used in orthodontics: multistrand wire retainers and fiber-reinforced composite retainers
For the lateral incisor and canine, maximum displacement was recorded at the apex palatal in both vertical loading and protrusive loading and the minimum displacement was found at the middle root labial of the lateral in both types of loading, while the minimum displacement in the canine was found at the middle root labial and apex labial in vertical loading and protrusive loading, respectively (Table 2)

Summary

Introduction

Contemporary retaining strategies in orthodontics basically include removable and fixed retainers. The main advantage of the use of multistrand wires is the irregular surface that offers increased mechanical retention for the composite without the need for the placement of retentive loops [3] Another asset is the flexibility of the wire that allows physiologic movement of the teeth, even when several adjacent teeth are bonded [4]. Comparison between Models 2 and 3 (in vertical loading) showed that FRC retainers that bonded at the upper third of lingual teeth surfaces made central and canine teeth move less than FRC retainers bonded at the middle third; for lateral teeth it was the opposite. FRC retainers bonded at the upper third of lingual teeth surfaces make central and canine teeth move less than FRC retainers bonded at the middle third in vertical loading; for lateral teeth it was the opposite

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Discussion

Conclusion