Comparative evaluation of micro-implant and headgear anchorage used with a pre-adjusted appliance system

The aim of this study was to compare and evaluate the anchorage effectiveness of using either micro-implants or extraoral headgear with the McLaughlin-Bennett-Trevisi (MBT) system. Thirty young Chinese adults (14 males and 16 females) aged 18-22 years with anterior bimaxillary protrusion were divided randomly into two equal groups, treated with the MBT system anchored by either micro-implants or headgear. Nine measurements obtained before and after treatment from lateral cephalometric radiographs were assessed for the two groups, using the Mann-Whitney U test with alpha = 0.05 for statistical significance. The maxillary incisors in the micro-implant group were significantly more retracted and intruded, while the lower incisors were more lingually inclined, than in the headgear group. The occlusal and mandibular planes were rotated more counterclockwise in the micro-implant group than in the headgear group (P < 0.05). Compared with headgear anchorage, micro-implant anchorage may counteract clockwise rotation of the occlusal and mandibular planes and result in different final positions for the maxillary and mandibular incisors.