Azeem Muhammad, Saleem Muhammad Mudassar, Liaquat Ahmad, Ul Haq Arfan, Ul Hamid Waheed, Masood Mina
Department of Orthodontics, Dental Section, Punjab Medical College, Faisalabad Medical University, Faisalabad, Pakistan.
Department of Oral & Maxillofacial Surgery, Islamabad Medical & Dental College, Islamabad, Pakistan.
Int Orthod. 2019 Mar;17(1):53-59. doi: 10.1016/j.ortho.2019.01.006. Epub 2019 Feb 13.
Anchorage reinforcement is an important issue in orthodontic treatment. There is a lack of evidence regarding the failure rate of mini-implants inserted in the retromolar (RM) area, therefore the purpose of this present study was to evaluate the failure rates of mini-implants inserted in the RM area and to evaluate the factors affecting their stability.
This retrospective cohort study of 102 patients (52 female, 55 male; mean age: 18.6years; SD: 5.2years) that had received 110 RM mini-implants for orthodontic treatment from 1.2.2012 to 1.6.2017 was conducted after IRB approval at the department of orthodontics. Clinical notes and photographic images of the patients were analysed to evaluate the dependent and independent variables. The primary outcome was mini-implant failure. Independent variables of patient related factors, mini-implant related factors, orthodontic related factors, surgical related factors, and maintenance-related factors were evaluated by logistic regression models for association to failure rates.
A 23.2% failure rate of mini-implants inserted in the RM area was observed. The patient's right side and inflammation were significantly associated with RM mini-implant failure. The odds ratios (relative risk) for mini-implant failure in the right side, and in mini-implants with inflammation around them were 0.166 and 0.188, respectively.
Failure rate for RM mini-implants were found to be 23.2%. To minimize RM mini-implant failure, clinicians should attempt to reduce inflammation around the mini-implants, especially for mini-implants placed on the right RM area.
支抗加强是正畸治疗中的一个重要问题。关于在后磨牙（RM）区植入微型种植体的失败率，目前缺乏相关证据。因此，本研究的目的是评估RM区植入微型种植体的失败率，并评估影响其稳定性的因素。
本回顾性队列研究对2012年2月1日至2017年6月1日期间在正畸科接受IRB批准后接受110颗RM微型种植体正畸治疗的102例患者（52例女性，55例男性；平均年龄：18.6岁；标准差：5.2岁）进行。分析患者的临床记录和照片图像，以评估相关的自变量和因变量。主要观察指标为微型种植体失败情况。通过逻辑回归模型评估患者相关因素、微型种植体相关因素、正畸相关因素、手术相关因素和维护相关因素等自变量与失败率的相关性。
观察到RM区植入的微型种植体失败率为23.2%。患者右侧及炎症与RM微型种植体失败显著相关。右侧微型种植体及周围有炎症的微型种植体失败的优势比（相对风险）分别为0.166和0.188。
RM微型种植体的失败率为23.2%。为尽量减少RM微型种植体的失败，临床医生应尝试减少微型种植体周围的炎症，尤其是放置在右侧RM区的微型种植体。
