Comparative outcomes of platelet concentrates and blood clot scaffolds for regenerative endodontic procedures: A systematic review of randomized controlled clinical trials.

Background: The main objective of this systematic review is to evaluate the effectiveness of platelet concentrates -Platelet-rich plasma (PRP) or Fibrin-rich plasma (PRF)- compared with blood clot (BC) as scaffolds for maturogenesis, in patients with immature permanent teeth with or without AP, in terms of the criteria for pulp revascularization success. Material and Methods: We reviewed randomized controlled clinical trials comparing regenerative endodontic therapies (maturogenesis) based on PRP or PRF versus the conventional BC approach, in necrotic teeth with or without apical periodontitis (AP) under clinical and radiographic criteria. We performed a strategic search in MEDLINE (PUBMED), EMBASE, and ISI Web of Science from inception to October 2022. This systematic review of the literature was developed following the Cochrane Collaboration and PRISMA statement recommendations. We used the Cochrane risk of bias tool v2 to assess the included studies' quality. We performed a qualitative synthesis of the evidence. Results: Ten randomized controlled clinical trials were included in this systematic review. Analyses of these studies suggest that maturogenesis is a successful therapy regardless of the method employed. However, further research should be conducted with more suitable research methodologies and more homogenous data for meta-analysis. Conclusions: Results from this systematic review suggest that BC maturogenesis approaches yield similar clinical and radiographic outcomes when compared to Platelet-concentrates based therapies (PRP and PRF). Key words:Maturogenesis, Revascularization, Platelet-rich plasma, Fibrin-rich plasma, blood clot, systematic review.

The Paradigm of the Inflammatory Radicular Cyst: Biological Aspects to be Considered.

Inflammatory radicular cysts (IRCs) are chronic lesions that follow the development of periapical granulomas (PGs). IRCs result from multiple inflammatory reactions led initially by several pro-inflammatory interleukins and growth factors that provoke the proliferation of epithelial cells derived from epithelial cell rests of Malassez present in the granulomatous tissue, followed by cyst formation and growth processes. Multiple theories have been proposed to help explain the molecular process involved in the development of the IRC from a PG. However, although multiple studies have demonstrated the presence of epithelial cells in most PGs, it is still not fully understood why not all PGs turn into IRCs, even though both are stages of the same inflammatory phenomenon and receive the same antigenic stimulus. Histopathological examination is currently the diagnostic gold standard for differentiating IRCs from PGs. Although multiple studies have evaluated the accuracy of non-invasive or minimally invasive methods in assessing the histopathological nature of the AP before the intervention, these studies' results are still controversial. This narrative review addresses the biological insights into the complex molecular mechanisms of IRC formation and its histopathological features. In addition, the relevant inflammatory molecular mediators for IRC development and the accuracy of non-invasive or minimally invasive diagnostic approaches are summarised. (EEJ-2022-03-041).