Tabrizi Reza, Behnia Hossein, Taherian Shahram, Hesami Nima
Assistant Professor of Oral and Maxillofacial Surgery, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Professor of Oral and Maxillofacial Surgery, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Oral Maxillofac Surg. 2017 Sep;75(9):1866-1872. doi: 10.1016/j.joms.2017.05.014. Epub 2017 May 24.
Implant fracture is a serious complication, which leads to treatment failure. The purpose of this study is to estimate the incidence of implant fractures and identify factors associated with them.
In this retrospective cohort study, the sample was derived from 2 implant centers. The predictors were grouped into the following categories: demographic, location of implant, physical characteristic of implant, implant-abutment connection, type of prosthesis, type of retention, and outcome variable (time to implant fracture). The Kaplan-Meier test was used to estimate implant survival. A Cox regression model was applied to evaluate the time-to-event effect of variables on implant fracture.
Of 18,700 implants, 37 (0.002%) had fractures. The 1- and 5-year risk of implant fracture was 0.38 per 1,000 and 1.46 per 1,000, respectively. Implant fractures more often occurred in the premolar and molar area (94.6%) than in the anterior of the jaws. The Pearson correlation test did not show any correlation between age, implant diameter, or implant length and time of fracture (P > .05). Analysis of the data by the log-rank test showed a significant difference for survival between cemented and screw-retained crowns (P = .001). The Cox regression model showed a hazard ratio of 0.23 for tapered implants versus cylindrical fixtures and for screw-retained crowns (hazard ratio, 296.54) versus cemented crowns.
According to this study, conical implants and screw-retained prostheses may have lower survival rates due to implant fracture.
种植体折断是一种严重的并发症，可导致治疗失败。本研究旨在评估种植体折断的发生率，并确定与之相关的因素。
在这项回顾性队列研究中，样本来自2个种植中心。预测因素分为以下几类：人口统计学因素、种植体位置、种植体物理特性、种植体-基台连接、修复体类型、固位类型以及结局变量（种植体折断时间）。采用Kaplan-Meier检验评估种植体生存率。应用Cox回归模型评估变量对种植体折断的事件发生时间效应。
在18700颗种植体中，37颗（0.002%）发生折断。种植体折断的1年和5年风险分别为每1000颗0.38例和每1000颗1.46例。种植体折断在前磨牙和磨牙区（94.6%）比颌骨前部更常见。Pearson相关性检验未显示年龄、种植体直径或种植体长度与折断时间之间存在任何相关性（P>0.05）。通过对数秩检验分析数据显示，黏固冠和螺丝固位冠的生存率存在显著差异（P = 0.001）。Cox回归模型显示，锥形种植体与圆柱形种植体相比，以及螺丝固位冠（风险比，296.54）与黏固冠相比，风险比为0.23。
根据本研究，锥形种植体和螺丝固位修复体可能因种植体折断而具有较低的生存率。
