Comparison of Anchor Loss and Rate of Retraction Between Modified Conventional Anchorage with a Power Arm and Titanium Mini-Implant in En-Masse Retraction- A Randomized Control Split Mouth Study

Abstract

Introduction:-This study was conducted to determine the efficiency of a new modified power arm with conventional intraoral anchorage units compared to a mini-implant for en-masse retraction of the maxillary anterior teeth in maxillary first premolar extraction case. The aim of the study was to compare the anchor loss and rate of retraction between modified conventional anchorage with a power arm and titanium mini-implant in case of en-masse retraction. Materials and methods:-15 participants requiring high anchorage in maxillary first premolar extraction cases were selected for this study. In each participant, the en-mass retraction was carried out with mini-implants on one side & modified conventional anchorage with a power arm on the other side. The choice of mode of retraction on the right and the left side was done on the basis of the coin flip method. Horizontal (Sagittal) positions of the maxillary first molar and rate of retraction were evaluated on lateral cephalogram & diagnostic cast. Results and observation:-Mean anchor loss was (+1.03 mm) on the conventional anchorage side &(-0.23 mm) distal movement of a maxillary molar on the mini-implant anchorage side. The rate of en-mass retraction was 0.77 mm per month on the mini-implant side and 0.69 mm per month on the conventional anchorage side. Conclusion:-Mini-implant acts as an efficient intraoral anchorage device for en-masse retraction and intrusion of maxillary anterior teeth. No anchorage loss was observed in either the horizontal or the vertical direction on the mini-implant side. Conventional modified anchorage with a power arm can be used in those cases in which anchorage loss of 1 to 1.5 mm is permissible. En-mass retraction is faster with mini-implant anchorage as compared with modified conventional anchorage with a power arm.