Platform switch and dental implants: A meta-analysisby Bruno Ramos Chrcanovic, Tomas Albrektsson, Ann Wennerberg

Journal of Dentistry


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JJOD 2402 1–18Review

Platform switch and dental implants:

A meta-analysis

Bruno Ramos Chrcanovic a,*, Tomas Albrektsson b,a, Ann Wennerberg a aDepartment of Prosthodontics, Faculty of Odontology, Malmo¨ University, Malmo¨, Sweden bDepartment of Biomaterials, Go¨teborg University, Go¨teborg, Sweden a r t i c l e i n f o

Article history:

Received 15 November 2014

Received in revised form 13 December 2014

Accepted 22 December 2014

Available online xxx


Dental implants

Platform switch

Implant failure rate

Marginal bone loss

Postoperative infection

Meta-analysis a b s t r a c t

Objectives: To test the null hypothesis of no difference in the implant failure rates, marginal bone loss (MBL) and postoperative infection in patients who received platform-switched implants or platform-matched implants, against the alternative hypothesis of a difference.

Data: Main search terms used in combination: dental implant, oral implant, platform switch, switched platform, platform mismatch, and dental implant–abutment design.

Sources: An electronic search without time or language restrictions was undertaken in

December/2014 in PubMed/Medline, Web of Science, Cochrane Oral Health Group Trials

Register plus hand-searching.

Study selection: Eligibility criteria included clinical human studies, either randomized or not.

Results: Twenty-eight publications Qwere included, with a total of 1216 platform-switched implants (16 failures; 1.32%) and 1157 platform-matched implants (13 failures; 1.12%).

Conclusions: There was less MBL loss at implants with platform-switching than at implants with platform-matching (mean difference 0.29, 95% CI 0.38 to 0.19; P < 0.00001). An increase of the mean difference of MBL between the procedures was observed with the increase in the follow-up time (P = 0.001) and with the increase of the mismatch between the implant platform and the abutment (P = 0.001). Due to lack of satisfactory information, meta-analyses for the outcomes ‘implant failure’ and ‘postoperative infection’ were not performed. The results of the present review should be interpreted with caution due to the presence of uncontrolled confounding factors in the included studies, most of them with short follow-up periods.

Clinical significance: The question whether platform-matched implants are more at risk for failure and loose more marginal bone than platform-switched implants has received increasing attention in the last years. As the philosophies of treatment alter over time, a periodic review of the different concepts is necessary to refine techniques and eliminate unnecessary procedures, forming a basis for optimum treatment. # 2015 Elsevier Ltd. All rights reserved. * Corresponding author at: Department of Prosthodontics, Faculty of Odontology, Malmo¨ University, Carl Gustafs va¨g 34, SE-205 06 Malmo¨,

Sweden. Tel.: +46 725 541 545; fax: +46 40 6658503.

E-mail addresses:, (B.R. Chrcanovic).

Available online at

ScienceDirect journal homepage: 0300-5712/# 2015 Elsevier Ltd. All rights reserved.Please cite this article in press as: Chrcanovic BR, et al. Platform switch and dental implants: A meta-analysis. Journal of Dentistry (2015), http:// 1Q4 O t

A i e i s a d k 1 w o t a c a p r t d i i p t l g r i m t

M l t a r t t t t p a a s p p a o 2

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JJOD 2402 1–18. Introduction ne reference criterion to evaluate implant success includes he assessment of changes in crestal bone level over time.1 fter a two-piece implant is uncovered, bone loss of 1.5–2 mm n the vertical axis and 1.4 mm in the horizontal axis was xpected with respect to micro-gap (the implant–abutment nterface).2 This pattern of bone loss is usually noted when ubmerged dental implants are restored using a matched butment and implant platform. An abutment with a smaller iameter than that of the implant platform (an approach nown as platform switching) was first observed in the mid980s, when larger-diameter implants were often restored ith narrower abutments because congruent abutments were ften unavailable.3 A radiographic follow-up study has found hat the placement of platform-switched implants resulted in smaller vertical change in the crestal bone level than was ommonly seen when restoring conventional implants with butments of matching diameter.4

The main hypothesis raised in the literature to explain this henomenon is the fact that the platform-switching concept equires the implant–abutment interface be placed away from he implant shoulder and closertowards the axis to increase the istance of the microgap from the bone,4 and thereby decrease ts bone resorptive effect5 caused by the bacterial microleakage.

Researchers have been trying to evaluate whether the nsertion of implants receiving abutment with a switched latform may influence the survival of dental implants and he marginal bone level (MBL). However, some studies may ack statistical power, given the small number of patients per roup in the clinical trials comparing the techniques. Recent eviews6,7 showed a significantly less mean MBL change at mplants with a platform-switched compared to a platformatched configuration. However, the authors stressed that he studies included were of relatively short follow-up periods. oreover, only prospective controlled studies were included, imiting the number of eligible papers. Adding more informaion from observational studies may aid in clinical reasoning nd establish a more solid foundation for causal inferences.8