3D FEM comparison of lingual and labial orthodontics in en masse retraction

Abstract

BackgroundThe aim of this study was to compare displacements and stress after en masse retraction of mandibular dentition with lingual and labial orthodontics using three-dimensional (3D) finite element models (FEM).MethodsA 3D FEM of each lower tooth was constructed and located as appropriate to Roth's prescription. The 0.018-in. GAC Roth Ovation labial and Ormco 7th Generation lingual brackets were virtually bonded to the lower teeth and threaded with 0.018 × 0.025- and 0.016 × 0.022-in. SS labial (Tru-Arch form, small size) and lingual (mushroom) archwires. En masse retraction was simulated by applying 300 g of distal force from the canine to the second premolar on the 0.016 × 0.022-in. SS labial and lingual archwires. The type of finite element used in the analysis was an eight-noded brick element. The Algor program (Algor Inc., Pittsburgh, PA, USA) was used to calculate the strains and displacements at each nodal point.ResultsLingual tipping and extrusion of the anterior dentition occurred with both archwires. At the premolars and first molars, intrusion, lingual movements, and lingual tipping were seen with the labial archwire, while intrusion was accompanied by labial movements, mesial tipping, and buccal rotation with lingual mechanics.ConclusionsLingual vs. labial bracket placement influences the pattern of tooth movement, but the stress that occurs around the teeth can be accurately mapped using a 3D FEM model.Electronic supplementary materialThe online version of this article (doi:10.1186/s40510-014-0038-9) contains supplementary material, which is available to authorized users.

Comparative assessment of the efficacy of closed helical loop and T-loop for space closure in lingual orthodontics—a finite element study

“…These changes will alter the loop conditions and thus potentially the mechanical properties. Even the linear properties of PDL are taken to be isotropic in FEM studies whereas the histological changes in PDL on application of orthodontic force can alter its material properties [10, 22, 30]. …”

In vitro assessment of competency for different lingual brackets in sliding mechanics

“…In labial orthodontics premolar extraction space closure can be carried out either by canine retraction or by enmass retraction whereas in lingual orthodontics enmass retraction is preferred because within the available short inter bracket span between canine and premolar the presence of archwire inset bend distal to canine would further interfere with space closure. [ 35 ] Even though, conflicting results have been reported[ 2 14 25 32 34 41 ] for labial orthodontics under wet condition (artificial saliva), studying the same in lingual orthodontics is essential as the lingual brackets are bathed in saliva than labial. [ 33 ]…”

Growth hormone receptor gene is related to root length and tooth length in human teeth

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