Effects of platelet concentrates on implant stability and marginal bone loss: a systematic review and meta-analysis.

BACKGROUND: Osseointegration is essential for the success and stability of implants. Platelet concentrates were reported to enhance osseointegration and improve implant stability. The purpose of this review is to systematically analyze the effects of platelet concentrates on implant stability and marginal bone loss. METHODS: Two researchers independently performed searches in the following databases (last searched on 21 July 2021): MEDLINE (PubMed), Cochrane Library, EMBASE, and Web of Science. In addition, a manual search was carried out on references of relevant reviews and initially included studies. All randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on the application of platelet concentrates in the implant surgery procedure were included. The risk of bias of RCTs and CCTs were assessed with a revised Cochrane risk of bias tool for randomized trials (RoB 2.0) and the risk of bias in non-randomized studies-of interventions (ROBINS-I) tool, respectively. Meta-analyses on implant stability and marginal bone loss were conducted. Researchers used mean difference or standardized mean difference as the effect size and calculated the 95% confidence interval. In addition, subgroup analysis was performed based on the following factors: type of platelet concentrates, method of application, and study design. RESULTS: Fourteen studies with 284 participants and 588 implants were included in the final analysis. 11 studies reported implant stability and 5 studies reported marginal bone level or marginal bone loss. 3 studies had high risk of bias. The meta-analysis results showed that platelet concentrates can significantly increase implant stability at 1 week (6 studies, 302 implants, MD 4.26, 95% CI 2.03-6.49, P < 0.001) and 4 weeks (8 studies, 373 implants, MD 0.67, 95% CI 0.46-0.88, P < 0.001) after insertion, significantly reduced marginal bone loss at 3 months after insertion (4 studies, 95 implants, mesial: MD - 0.33, 95% CI - 0.46 to - 0.20, P < 0.001; distal: MD - 0.38, 95% CI - 0.54 to - 0.22, P < 0.001). However, the improvement of implant stability at 12 weeks after insertion was limited (P = 0.10). Subgroup analysis showed that PRP did not significantly improve implant stability at 1 week and 4 weeks after insertion (P = 0.38, P = 0.17). Platelet concentrates only placed in the implant sites did not significantly improve implant stability at 1 week after insertion (P = 0.20). CONCLUSIONS: Platelet concentrates can significantly improve implant stability and reduce marginal bone loss in the short term. Large-scale studies with long follow-up periods are required to explore their long-term effects and compare effects of different types. TRIAL REGISTRATION: This study was registered on PROSPERO, with the Registration Number being CRD42021270214.