[Analysis of risk factors of 19 fractured implants].
To analyze the incidence and possible risk factors of 19 fractured implants out of 8 468 implants in 3 184 cases. During the 22-year clinical practice, clinical records of 18 patients with 19 fractured implants in 3 184 cases with 8 468 implants were analyzed to determine the following factors: location of the fractured implants, prosthodontics option, date of implant fracture, dimensions of fractured implants, complications prior to implant fracture and parafunctional habit. An evaluation of fractured implants was performed to identify possible factors that may predispose an implant to a higher risk of fracture. Overall, the average duration of service of the implants was (7.0±4.5) years. Implant fracture occurred in 7 Camlog implants, 7 Nobel replace implants, 3 Ankylos implants and 2 Brånemark implants. No Thommen implant fractures were recorded. Amongst the 19 fractured implants, 8 occurred at the thinnest wall portion of the implant neck, 8 at the end of screw and 3 at the self-tapping thread region. All fractures were observed after functional loading. Furthermore, 9/19 (47.4%) of fractures occurred in the maxilla, indicating similar incidence rates in both arches (0.065). Most of fractures (16/19) occurred in the molar region and 18/19 in single implant-supported restorations. Totally 17 cases had received metal occlusal restorations. In 6 cases (35.5%), previous bone destruction apically extending to the level of implant fracture was documented before any clinical signs of fracture. Three fractured implants were removed and simultaneously re-implanted with larger-diameter implants, while the rest of the cases were left to heal, followed by a second-stage surgery. Within the limitation of this analysis, the study demonstrated that appropriate implant-abutment connection design, implant diameter, prosthetic strategy and bone resorption are crucial to the long-term performance of implants. There is no significant difference of fractures rates in both archs.
通过分析种植体负重后折裂折断的原因，探讨其临床应对处理措施，为临床提供参考。 回顾分析1994年4月至2016年12月在北京大学口腔医学院·口腔医院种植科及第四门诊部就诊、由作者团队种植治疗的种植病例3 184例，8 468枚种植体，共发现18例患者的19枚种植体折裂折断，通过统计折裂折断种植体的牙位、连接方式、负重时间、修复方式、修复材料、并发症及患者其他因素等，归纳分析引起种植体折裂折断的危险因素及预防措施。 19枚折裂折断种植体的使用时间为（7.0±4.5）年。19枚折裂折断的种植体包括Camlog系统种植体7枚、Branemark种植体2枚、Nobel Replace种植体7枚、Ankylos种植体3枚。Thommen系统尚未发现种植体折断。8/19的植体折断部位位于颈部抗旋槽内，8/19发生在固位螺丝根方水平处，另有3/19发生在固位螺丝处。所有折断均发生在修复负重后，均为后牙区牙列缺损病例，其中磨牙区占16/19。上颌（9/19）与下颌（10/19）种植体折断发生率差异无统计学意义（0.065）。单冠修复所占比例为18/19。17枚为金属■面的修复方式。19枚折断植体中6枚在发生折断前出现牙槽骨杯状吸收。3枚折断种植体取出后同期植入大直径种植体，其余折断植体均未做同期处理。 种植体折断与种植体-基台设计、种植体直径、修复方式及牙槽骨吸收等因素有关；种植体折断在上下颌的发生率无显著差别。.