Previous studies and reviews have suggested that platform switching where the abutment has a smaller diameter then the implant platform on which is placed has a beneficial effect on marginal bone preservation.
The aim of this review was to evaluate the possible benefits of platform-switching (PSW) implants when compared to regular platform (RP) implants in the categories of bone preservation and longevity.
Searches were conducted in the Medline, Embase and Cochrane Central Register of Controlled Trials supplemented by a manual search of the journals, Clinical Implant Dentistry and Related Research, Clinical Oral Implant Research, Implant Dentistry, International Journal of Oral and Maxillofacial Surgery, Journal of Clinical Periodontology, Journal of Dental Research, Journal of Maxillofacial and Oral Surgery, Journal of Oral Implantology, Journal of Periodontology, Journal of Prosthetic Dentistry, Journal of Prosthodontics, Journal of Oral Rehabilitation, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, Periodontology 2000, International Journal of Oral and Maxillofacial Implants, and International Journal of Periodontics and Restorative Dentistry.
Two reviewers independently selected studies with study quality being assessed using the Jadad scale. Studies comparing implants with a platform- switching geometry with implants with a regular abutment with a main outcomes of bone loss and implant survival rates were considered. Only English language studies and those with a minimum of 12 months follow up were included.
- 25 studies involving a total of 1098 patients and 2310 implants were included.
- 17 were RCTs and 8 controlled prospective studies.
- Meta-analysis of 17 RCT found a significant bone loss in the control group compared with the PSW group; Mean Difference (MD) = -0.41mm (95%CI; -0.58 to -0.24)
- Meta analysis (25 studies) MD= -0.41mm (95%CI; -0.52 to -0.29)
- Of the total implants, 21 PSW implants and 17 RP implants failed.
- Meta analysis (25 studies) found no statistically significant difference in the failure of implants RR = 1.10 (95%CI; 0.6–2.02)
The authors concluded:
platform-switching implants showed greater relevant bone preservation when compared to regular platform implants. Platform-switching implants showed a failure rate similar to hat of regular platform implants. RCTs with long follow-up periods should be performed.
Three major databases have ben searched for this review although studies are restricted to those published in English, which may mean that some studies have been missed. Last year we covered a review by Chrcanovic et al (Dental Elf 1st May 2015), which searched a wider range of databases and also included retrospective studies. The Chrcanovic review search included 18 RCTs compared with 17 in this current review. Both reviews found that there was less bone loss in PSW implants although the current review reports a larger mean difference MD = -0.41mm (95%CI; -0.58 to -0.24) compare with Chrcanovic MD= -0.29mm (95% CI; -0.38 to -0.19).
While both review have included a large number of RCTs they have decided to include non-randomised studies. In this new review finding from the RCTs for bone loss have been reported separately in the Chrcanovic review all studies designs are included together and analysed after different follow-up periods.
Santiago JF Junior, de Souza Batista VE, Verri FR, Honório HM, de Mello CC, Almeida DA, Pellizzer EP. Platform-switching implants and bone preservation: a systematic review and meta-analysis. Int J Oral Maxillofac Surg. 2015 Dec 23. pii: S0901-5027(15)01422-8. doi: 10.1016/j.ijom.2015.11.009. [Epub ahead of print] Review. PubMed PMID: 26723496