Abstract:

 Objective  This study aims to compare the treatment outcomes in patients with maxillary dentoalveolar protrusion by applying different anchorage methods via three-dimensional model measurement. Methods  A total of 46 patients with maxillary dentoalveolar protrusion treated with bilateral maxillary first premolar extractions and high anchorage were selected. The subjects were randomly divided into three groups according to the type of anchorage applied, which included implant, extraoral, and Nance arch anchorages. The maxillary dental models were made before treatment and after space closure of maxilla. The movements of the maxillary central incisors and first molars were measured via a three-dimensional model measurement, and the amounts of movement were compared among the three groups. Results  The sagittal lingual movements of the maxillary central incisors were (-6.661±1.328), (-5.939±1.806), and (-5.788±2.009) mm for the implant, extraoral, and Nance arch anchorage groups, respectively, with no significant difference among the three groups (P=0.121). The corresponding vertical movements of the maxillary central incisors were (0.129±1.815) mm intrusion, and (-2.162±2.026), (-2.623±1.776) mm extrusion. Significant difference was found between the implant anchorage group and the other groups (P<0.05). The corresponding sagittal mesial movements of the maxillary first molars were (0.608±1.045), (1.445±1.462), and (1.503±0.945) mm. The corresponding vertical movements of the maxillary first molars were (0.720±0.805) mm intrusion, (0.076±0.986) mm intrusion, and (-0.072±0.690) mm extrusion. Significant difference was found between the implant anchorage group and the other two groups (P< 0.05). In the transverse direction, the first molars all moved lingually with no significant difference among the three groups (P>0.05). Conclusion  Implant anchorage may be superior in the vertical control of the maxillary incisors and in the sagittal, as well as in the vertical control of the maxillary molars, compared with the traditional anchorages during the treatment of patients with maxillary dentoalveolar protrusion.

Key words:  anchorage, maxillary dentoalveolar protrusion, three-dimensional model measurement