This critical summary from the American Dental Association – Evidence-based Center (ADA-EBD) looks at a 2010 systematic review from Atieh et al. The aim of the review was to assess whether platform switching (the placement of a smaller diameter prosthetic component on a larger diameter implant fixture) improved survival rate and bone loss.
The commentator notes that, although the reviews used a sound methodological approach, only 10 small studies were included, 3 of these being controlled trials, the remainder being randomised controlled trials. The commentator highlighted issues raised by the reviewers regarding the bone height measurement. it was also noted that the longest study was only 5 years.
The commentator concluded
Implant survival was not affected by platform switching. Limited short-term evidence indicated that platform switching preserves peri-implant bone height by a relatively small amount (0.37 mm) compared with platform matching.
A more recent systematic review covering this topic has been published by Al-Nsour et al 2012. Their review included 9 studies ( 6 randomised controlled trials). They concluded:-
Based on the current evidence, the use of abutments with a smaller diameter than their corresponding implant platforms seems to exert beneficial effects on peri-implant marginal bone. Some potential confounding factors, for example, the apicocoronal position of implants in relation to crestal bone, the presence of various implant microtextures, the degree of platform switch, and the reliability of examination methods, should be considered when interpreting the present results.
Atieh MA, Ibrahim HM, Atieh AH. Platform switching for marginal bone preservation around dental implants: a systematic review and meta-analysis. J Periodontol. 2010 Oct;81(10):1350-66. Review. PubMed PMID: 20575657
Al-Nsour MM, Chan HL, Wang HL. Effect of the platform-switching technique on preservation of peri-implant marginal bone: a systematic review. Int J Oral Maxillofac Implants. 2012 Jan-Feb;27(1):138-45. Review. PubMed PMID: 22299090