Abstract:

Objective To evaluate the clinical efficacy of asymmetric couple in uprighting the highly and mesially impacted mandibular second molar. Methods Eighteen adolescents with highly and mesially impacted mandibular second molars were selected. One miniscrew was implanted into the buccal shelf. The miniscrew and the posterior segment constituted the anchorage. The tube was bonded on the disto-buccal side of the second molar. After the NiTi segmental archwire was placed, the asymmetric couple was formed on both sides. After they were almost uprighted, the position of the buccal tube was adjusted to improve the occlusion. Graphpad prism 6.0 software package was used for paired t-test. Results All tilted molars were uprighted, and there was no occlusal interference during the treatment. The final local occlusion was good, and no obvious root resorption happened. The height of the distal alveolar bone of the adjacent first molar increased significantly, and the vertical distance from the mesial buccal cusp to the mandibular plane remained stable. Conclusion The asymmetric couple formed by miniscrew and NiTi segmental archwire can effectively erect the highly impacted mandibular second molar and control its vertical position at the same time.

Key words: miniscrew, mesially tilted molar, asymmetric couple, NiTi segment archwire