by The Dental Elf via Evidence of small benefit in peri-implant bone loss seen in first 5 years with platform switching » The Dental Elf.
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 randomized 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.
Comment
A more recent systematic review covering this topic has been published by Al-Nsour et al 2012. Their review included 9 studies (6 randomized 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.
Related articles
- ADA-EBD Critical Summary – Platform switching reduces peri-implants bone loss
- Commentary on Atieh et al from Evidence-based Dentistry Journal
- 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
- A Proposed Classification for Peri-Implantitis (perioandimplants.wordpress.com)
LovePerio 
Would a difference of 0.37 mm crestal bone loss be considered of clinical significance?
0.37mm is a small difference however I still think could play a major role in the outcome of our implant surgery. Keep in mind the peri-implant bone loss has a vertical but also an horizontal factor (we also lose bone in an horizontal or interproximal fashion). 0.37mm plays an important difference in the anterior portion of the mouth were the loss of even a small portion of bone could mean not having an interproximal papilla.