Effect of archwire dimensions in combination with different extraction space widths on tooth movement during space closure in sliding mechanics: long-term 3D finite element analysis

Purpose The objective of this study was to investigate the long-term effect of different archwire dimensions in combination with different extraction space widths on the biomechanical behaviour of tooth movement during space closure using sliding mechanics.Materials and Methods A finite element model of the maxillary dentition was constructed with 0.022 × 0.028-in brackets and three different archwires of 0.017 × 0.025-in, 0.018 × 0.025-in, and 0.019 × 0.025-in. The extraction space was set as 4 or 7 mm. En-masse retraction was performed by applying a retraction force from 4 mm power arm. We compared the degree of labio-lingual tipping of the central incisor, mesio-distal tipping of the canine, mesio-distal and bucco-lingual tipping of the first molar, rotation of the occlusal plane and the velocity of space closure when varying the archwire dimesions in combination with different extraction space widths.Results The central incisor showed lingual crown tipping for all three archwire dimensions even with 4 mm power arm. The larger the archwire dimension, the less substantially the incisor tipped lingually. The first molar showed lingual tipping with small size archwires. The wider the residual extraction space, the more substantially the central incisor tipped lingually.Conclusions The larger the archwire dimension, namely, the better controlled tooth movement we try to achieve, the longer the treatment duration is required.