Sir John Walsh Research Institute, School of Dentistry, University of Otago, Dunedin, New Zealand.
J Periodontol. 2010 Oct;81(10):1350-66. doi: 10.1902/jop.2010.100232.
Platform switching for maintaining peri-implant bone levels has gained popularity among implant manufacturers over the last few years. However, the assumption that the inward shifting of the implant-abutment junction may preserve crestal bone was primarily based on serendipitous finding rather than scientific evidence. The objectives of the present study were to systematically review radiographic marginal bone-level changes and the survival of platform-switched implants compared to conventional platform-matched implants.
A literature search of electronic databases (MEDLINE, EMBASE, The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials, the U.K. National Research Register, the Australian New Zealand Clinical Trials Registry, the Database of Abstracts of Reviews of Effectiveness, and Conference Proceedings Citation Index) was performed up to March 15, 2010. Hand searches included several dental journals, and authors were contacted for missing information. Controlled trials that compared marginal bone-level changes around platform-switched dental implants with those restored with platform-matched prostheses were selected. The review and meta-analysis were done according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Data were analyzed using two meta-analytic statistical packages. Mean differences (MDs) were calculated for analyzing continuous data, and risk ratios (RRs) were used for dichotomous data with 95% confidence intervals (CIs).
Ten studies with 1,239 implants were included. The marginal bone loss around platform-switched implants was significantly less than around platform-matched implants (MD: -0.37; 95% CI: -0.55 to -0.20; P <0.0001). No statistically significant difference was detected for implant failures between the two groups (RR: 0.93; 95% CI: 0.34 to 2.95; P = 0.89). Subgroup analyses showed that an implant-abutment diameter difference > or= 0.4 was associated with a more favorable bone response.
The review and meta-analysis show that platform switching may preserve interimplant bone height and soft tissue levels. The degree of marginal bone resorption is inversely related to the extent of the implant-abutment mismatch. Further long-term, well-conducted, randomized controlled studies are needed to confirm the validity of this concept.
在过去几年中，种植体制造商越来越热衷于使用平台转换来维持种植体周围的骨水平。然而，种植体-基台连接内移可能保留牙槽嵴骨的假设主要基于偶然发现，而不是科学证据。本研究的目的是系统地评价平台转换种植体与传统平台匹配种植体相比，其放射学边缘骨水平变化和种植体存活率。
对电子数据库（MEDLINE、EMBASE、Cochrane 口腔健康组试验注册库、Cochrane 中心对照试验注册库、英国国家研究注册库、澳大利亚新西兰临床试验注册库、疗效评价文摘数据库和会议论文引文索引）进行文献检索，检索时间截至 2010 年 3 月 15 日。手工检索包括几种牙科杂志，并联系作者以获取缺失信息。选择了比较平台转换牙科种植体周围边缘骨水平变化与用平台匹配修复体修复的种植体的对照试验。根据系统评价和荟萃分析首选报告项目的指南进行综述和荟萃分析。使用两个荟萃分析统计软件包分析数据。对连续数据进行分析时采用均数差（MD），对二分类数据采用风险比（RR），置信区间（CI）为 95%。
纳入 10 项研究共 1239 枚种植体。平台转换种植体周围的边缘骨丢失明显小于平台匹配种植体（MD：-0.37；95%CI：-0.55 至-0.20；P<0.0001）。两组之间的种植体失败无统计学差异（RR：0.93；95%CI：0.34 至 2.95；P=0.89）。亚组分析显示，种植体-基台直径差>或=0.4 与更好的骨反应相关。
综述和荟萃分析表明，平台转换可能保留种植体之间的骨高度和软组织水平。边缘骨吸收的程度与种植体-基台不匹配的程度成反比。需要进一步进行长期、精心设计、随机对照研究来证实这一概念的有效性。
