A finite element method study to compare enmasse retraction of maxillary anteriors using mini implant and conventional anchorage method

Abstract

Increased upper lip procumbency is associated with protrusive maxillary dentition in Angle’s class I malocclusion, creating unaesthetic facial profile, leading to the need of orthodontic treatment where Enmasse retraction will require maximum anchorage.The present study was conducted to compare Enmasse retraction of maxillary anteriors using mini implant and conventional anchorage in Angle’s Class I malocclusion with bimaxillary protrusion. A numeric approach was adopted. Finite element method was used to determine the stress and displacement of various components at a given time by dividing it into two groups namely, Implant arrangement and T- loop arrangement for enmasse retraction. Significant differences were observed when the stress values were compared between Implant arrangement and T-loop arrangement. In Implant arrangement highest stress values were seen around the lateral incisors and in T loop arrangement stresses were found around canine and premolar. Comparison of displacement in both arrangements gave results of greater displacement in anterior and posterior segments in T-loop arrangement. Mini implants were considered more effective for enmasse retraction but in this study, it was found that although the rate of retraction/ displacement was more in T-loop arrangement but Mini implants in implant arrangement served as an absolute anchorage.