Psoriasis, Psoriatic Arthritis, and Periodontitis: An Umbrella Review of Current Evidence v1

Background: Psoriasis, psoriatic arthritis, and periodontitis are chronic inflammatory conditions. While traditionally studied as distinct diseases, a growing body of evidence suggests a strong association and potential shared inflammatory pathways, with key mediators such as TNF-α and IL-17 playing a role. However, the existing evidence remains fragmented across multiple systematic reviews and meta-analyses, preventing a comprehensive, high-level overview of their interconnections. Objective: This umbrella review aims to systematically synthesize the existing evidence from systematic reviews and meta-analyses evaluating the association between Psoriasis and Psoriatic Arthritis and periodontitis. The goal is to assess the strength, consistency, and quality of this association, and to identify potential mechanisms and clinical implications. Methods: A comprehensive literature search was conducted across PubMed, Embase, Scopus, Web of Science, and the Cochrane Library up to July 14, 2025, using predefined PRISMA-S compliant strategies. Additional forward and backward citation tracking was performed. Eligible studies include systematic reviews and/or meta-analyses involving human subjects with RA and/or periodontitis. Narrative reviews and primary studies were excluded. Study selection, data extraction, and quality assessment (using AMSTAR 2) will be performed by two independent reviewers. Expected outcomes: The review will provide an overarching summary of the current evidence linking PsA or PsO and periodontitis, clarify whether consistent associations have been found, and identify methodological strengths and gaps across the existing literature. Findings will inform both clinical practice and future research on the inflammatory overlap between oral and systemic autoimmune conditions.