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Desquamative gingivitis is usually a manifestation of autoimmune mucocutaneous disorders (e.g., oral lichen planus, mucous-membrane pemphigoid); while bacteria can be found in the sulcus, their etiologic significance is unclear, making the contribution of dental plaque obscure [Arduino et al., 2017, PMID 28304209]. In contrast, conventional periodontitis, juvenile (aggressive) periodontitis, and necrotising ulcerative gingivitis have well-documented pathogenic bacteria and a direct plaque-mediated origin.