Transpalatalª²Nance arch on reinforcing anchorage: A clinical study on bimaxillary protrusion

    HUO Na, DUAN Yinª²Zhong, HAN Chun, ZHANG Juª²Ju

    Department of Orthodontics, College of Stomatology, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To study the effect of transpalatalª²Nance arch on reinforcing anchorage in the treatment of bimaxillary protrusion. METHODS: A total of 34 patients (aged 12-26 years) with Class¢ñmalocclusion and bimaxillary protrusion were selected and treated with the transpalatalª²Nance arch on reinforcing anchorage after the extraction of first premolar in each quadrant. Lateral cephalometric radiographs and casts were taken before and after treatment for analysis. RESULTS: The average forward movement of the first maxillary molar was (1.50¡À0.85) mm, but still less than 1/3 of the extraction space. The changes in the backward movement and reduction of the axial inclination of the incisors were significant and the average backward movements of the upper and lower incisors were (4.73¡À2.64) mm and (5.52¡À4.62) mm respectively. The soft tissue profile (Lsª²E, Liª²E, Cmª²Snª²Ls, Pg¡äB¡äª²FH, A¡äL sª²FH and Z angle) was greatly improved (P<0.01). The vertical distance of the first maxillary molar to the palatal plane was increased (P<0.05), but the changes in GoGnª²Sn angle and ALFH/AFH were not significant (P¡Ý0.05). The changes of the alveolar bone (SNA, SNB and ANB) were not significant (P¡Ý0.05). CONCLUSION: The transpalatalª²Nance arch anchorage system is an effective and simple anchorage with threeª²dimensional anchorage function. It can be used as a noncooperative strong anchorage in the treatment of bimaxillary protrusion. ......