Abstract: PURPOSE: In this study, micro-implants were used in 15 adult patients with mild and moderate bimaxillary arch protrusion or crowding. Cephalometric analysis was used to analyze hard and soft-tissues change before and after treatment, with the aim to investigate the effects of treatment on adult bimaxillary arch protrusion with micro-implant anchorage. METHODS: Fifteen adult patients with mild and moderate bimaxillary arch protrusion were selected in this study. Micro-implants were inserted into the zygomaticoalveolar ridge of maxilla and the external oblique line of mandible. A NiTi coil spring was attached to the micro-implant to drag the whole upper and lower dentition for distal movement. Cephalometrics were taken before and after treatment, and the changes of soft and hard-tissue profile were studied. SPSS13.0 software package was used to analyze the data. RESULTS: ①Sixty micro-implants remained stable.②SNA, SNB had no significant changes (P>0.05), and the relationship between the maxilla and the mandible did not change significantly. U1/NA, U1-NA, L1/NB, L1-NB and U1/L1 changes in hard tissue had significant difference in cephalometric measurement (P<0.05). The upper and lower anterior teeth were more retrusive, and the tipping of incisor decreased significantly.③Cephalometric analysis showed that lateral appearance improved and soft tissue cephalometric-related measurements such as Cm-Sn-UL,LL-B’-Pos increased significantly (P<0.01). ④Molars and incisors acquired distal movement. CONCLUSIONS: Micro-implant can provide not only excellent skeletal anchorage but also a novel way to distalize the whole dentition efficiently.

Key words: Micro-implant anchorage, Bimaxillary arch protrusion, Whole dentition distalization movement