To assess the clinical effectiveness of mild to moderate skeletal Class Ⅲ malocclusion cases by placing upper incisor brackets upside down with straight wire appliance.

Sixty-six patients with mild to moderate skeletal Class Ⅲ in the early permanent dentition were chosen and randomly allocated to two groups. Thirty three patients were treated with brackets bonded commonly (17 non-extraction and 16 extraction) and the other 33 patients were treated with brackets bonded upside down (18 non-extraction and 15 extraction). Lateral cephalometric radiographs were taken and measured before and after treatment, and statistical analysis was performed.

In non-extraction cases, there were significant differences of the change with treatment of SNA(°), U1-SN(°) and U1-NA(°) between the experimental group and the control group (P＜0.05). In extraction cases, there were significant differences of the change with treatment of SNA(°), U1-SN(°), U1-NA(mm), U1-NA(°), L1-MP(°), L1-NB(mm), L1-NB(°) and U1-L1(°) between the experimental group and the control group (P＜0.05).

Bonding upper incisor brackets upside down could increase labial roots torque of upper incisors in skeletal Class Ⅲ malocclusion cases, which helped improve esthetic and function of the patients to some extent.