Abstract: PURPOSE: To evaluate the effect of the low-friction self-locking bracket system combined with micro-implant anchorage in the treatment of adult bimaxillary protrusion. METHODS: A total of 106 patients with bimaxillary protrusion admitted to Changsha Stomatological Hospital from March 2020 to March 2025 were selected and divided into the control group and the experimental group by blind computer random sequence, with 53 cases in each group. The control group was treated with the low-friction self-locking bracket system, while the experimental group was treated with the low-friction self-locking bracket system combined with micro-implant anchorage. The treatment duration, cephalometric angle parameters, cephalometric linear parameters, soft tissue cephalometric parameters, periodontal indices, periodontal microenvironmental inflammatory markers and the occurrence of complications were compared between the two groups. RESULTS: The time for closing the tooth extraction gap and the orthodontic treatment time in the experimental group were significantly shorter than those in the control group (P<0.05). After treatment, the difference in the increase of U1-L1 in the experimental group was significantly higher than that in the control group, and the differences in the reduction of the SNA Angle and L1-MP Angle were significantly higher than those in the control group (P<0.01). The UL-E lines and LL-E lines in both groups were significantly reduced, and those in the experimental group were even smaller (P<0.05). After treatment, the chin groove inclination angle, nasolabial angle and chin labial groove depth in both groups increased significantly, and those in the experimental group were larger (P<0.05); the U1-NA and U1-APo levels in both groups were significantly decreased, and those in the experimental group were even lower (P<0.05). After treatment, the scores of gingival index (GI), plaque index (PLI) and sulcus bleeding index (SBI) in both groups decreased significantly, and those in the experimental group were even lower(P<0.05). During the treatment period, no serious complications occurred in either group. CONCLUSIONS: The low-friction self-locking bracket system combined with micro-implant anchorage can shorten the treatment time while improving facial aesthetics in the treatment of adult bimaxillary protrusion.

Key words: Low-friction self-locking bracket system, Micro-implant anchorage, Bimaxillary protrusion