Research on Maxillary Anterior Accompanied with Posterior Mini-implant Anchorage Treatment in Patients with Lip Incompetence

Objective:To determine the efficiency of maxillary anterior accompanied with posterior mini-implant as intraoral anchorage used in the patients with lip incompetence.Methods:Eighteen subjects with lip incompetence were allocated in the study.The patients were divided into two groups:group A(3 mini-implants anchorage) with 9 patients and group B(Nance holding arch) with 9 patients.Cephalometric analysis was performed before and after the treatment.All data were analyzed by SPSS15.0 software.Results:1)Teeth:The distance and angle of retracted anterior teeth and the reduce of uncovered incisors were larger in group A than group B(P0.01).The mesial movement of incisor's apex(P0.05) and molar(P0.01) were less in group A.The anterior teeth were obviously intruded in group A and elongated in group B(P0.01).Molar's position maintained in group A and moved occlusally in group B(P0.05).2)Bone:The absorption of bone at SPr point was greater in group A(P0.05).Conclusion:Combined use of anterior and posterior mini-implants can provide stronger anchorage to retract,intrude and control root movement of incisors than conventional anchorage for patients with lip incompetence.