Susarla Srinivas M, Chuang Sung-Kiang, Dodson Thomas B
Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA 02114, USA.
J Oral Maxillofac Surg. 2008 Feb;66(2):251-5. doi: 10.1016/j.joms.2007.09.012.
The purpose of this study was to estimate 1-year survival for delayed versus immediately loaded implants and identify risk factors for implant failure.
This was a retrospective cohort study, consisting of a sample of subjects who had greater than or equal to 1 Bicon dental implant (Bicon, Boston, MA) placed over a 13-year period. The primary predictor variable was method of implant loading: delayed (3 to 6 months after placement) or immediately after insertion. Secondary predictor variables were classified as demographic, anatomic, implant/abutment, and reconstructive. The outcome variable was implant failure, defined as removal of the implant, and was recorded as months of survival. Descriptive, Kaplan-Meier, and univariate Cox proportional hazards statistics were computed. Univariate associations with P <or= .15 and biologically relevant variables (eg, age, gender) were included in a marginal multiple Cox regression model. In the multiple model, a P value of <or= .05 was considered statistically significant.
The study sample consisted of 677 subjects who had 2,349 delayed-loaded dental implants and 178 patients who had 477 immediate-loaded implants. The unadjusted 1-year survival estimates for the delayed and immediate loading groups were 95.5% and 90.3%, respectively (P < .01). In the marginal multiple Cox regression model, immediate loading, current tobacco use, maxillary implants, and shorter implants were associated with failure (P <or= .05).
In this study, implants loaded immediately were 2.7 times (after adjusting) more likely to fail at 1 year compared with delayed-loaded implants.
本研究旨在评估延期加载与即刻加载种植体的1年生存率，并确定种植体失败的风险因素。
这是一项回顾性队列研究，样本为在13年期间植入至少1颗Bicon牙科种植体（Bicon，波士顿，马萨诸塞州）的受试者。主要预测变量是种植体加载方式：延期（植入后3至6个月）或即刻加载。次要预测变量分为人口统计学、解剖学、种植体/基台和重建相关变量。结局变量是种植体失败，定义为种植体取出，并记录生存月数。计算描述性、Kaplan-Meier和单变量Cox比例风险统计量。单变量分析中P≤0.15且具有生物学相关性的变量（如年龄、性别）被纳入边际多元Cox回归模型。在多元模型中，P值≤0.05被认为具有统计学意义。
研究样本包括677名受试者，他们植入了2349颗延期加载的牙科种植体，以及178名患者，他们植入了477颗即刻加载的种植体。延期加载组和即刻加载组未经调整的1年生存率估计分别为95.5%和90.3%（P<0.01）。在边际多元Cox回归模型中，即刻加载、当前吸烟、上颌种植体和较短的种植体与失败相关（P≤0.05）。
在本研究中，与延期加载的种植体相比，即刻加载的种植体在1年时失败的可能性（调整后）高2.7倍。
