Platform-matched Implants Research Articles

Evidence supporting platform-switching to preserve marginal bone levels not definitive

MEDLINE, EMBASE, The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), UK National Research Register, Australian New Zealand Clinical Trials Registry (ANZCTR), Database of Abstracts of Reviews of Effectiveness (DARE), ISI Proceedings for relevant conference abstracts. The search strategy used keywords but not subject heading terms. A number of relevant journals were hand searched (seven most recent years) and authors were contacted in the absence of complete data. Randomised controlled trials (RCT) or controlled clinical trials (CCT) reported in English only, that compared platform-switched to platform-matched implants were eligible. A minimum of 10 implants had to have been placed in the platform-switched group (it is unclear if there was a minimum for the comparison group) and they had to have been followed up for a minimum of 12 months. Primary outcome was marginal bone level changes. Secondary outcome was implant failure rate. Data were extracted by more than one author using a data extraction form. Quality assessment was done using the Jadad scale. Meta-analysis was conducted using fixed effects model in the absence of significant heterogeneity, and the random effects model where heterogeneity was greater. Statistical heterogeneity was assessed using the chi(2) and I(2) tests. Sensitivity and subgroup analyses were planned to identify any potential causes of heterogeneity. Ten studies including 1239 implants were included and all were published 2007-2010. Seven were RCTs, three were CCTs. Range of observation was 12-60 months. Methodological quality was assessed as 'satisfactory'. Chi(2) =126.79 (P <0.0001), I(2) = 91% indicating significant statistical heterogeneity. Thus the random effects model was used to synthesise the data. Bone loss in the platform-matched implant group was greater with a mean difference of -0.37 mm (95% CI -0.55 to -0.20, P <0.0001). This is based on the longest follow-up interval from each trial (therefore could be anywhere between 12 and 60 months). There was no significant difference in implant failure. Platform-switching may preserve vertical crestal bone levels more than platform-matching when placing implants.

Platform Switching for Marginal Bone Preservation Around Dental Implants: A Systematic Review and Meta‐Analysis

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.