Introduction and objective:
Periodontitis is a multifactorial inflammatory disease triggered by the dysbiosis of subgingival microbial biofilm and fuelled by host immune response. Periodontal inflammation may affect other systems and organs. Systemic inflammation is also a main characteristic of severe forms of Corona-Virus-Disease-2019 (COVID-19). Some genetic/ environmental factors in periodontitis patients might implicate the course of COVID-19, thus, the aim of the study was to analyse the association of periodontitis with COVID-19 complications.

Review methods:
Literature available on 13 August 2022 was searched by using the PubMed, Web of Science and Google Scholar databases. Articles were selected that contained the key words: COVID-19, SARS-CoV-2, periodontitis, oral manifestation.

Brief description of the state of knowledge:
From the initial serach, 26 articles were retrieved for final analysis. Available data have shown that periodontitis may be a predisposing factor for the development of severe COVID-19. Periodontitis was associated with increased rates of hospitalization, assisted ventilation and death due to COVID-19 complications. Similar inflammatory pathways are activated in COVID-19 and periodontitis, and periodontal pathogens may contribute to a more severe course of COVID-19.

Since some evidence confirms a relationship between periodontitis and severity of COVID-19, it is essential to maintain periodontal health and good oral hygiene as an important measure for the prevention and management of COVID-19 and its complications.

Marouf N, Cai W, Said KN, et al. Association between periodontitis and severity of COVID-19 infection: A case-control study. J Clin Periodontol. 2021;48(4):483–491.
Brock M, Bahammam S, Sima C. The Relationships Among Periodontitis, Pneumonia and COVID-19. Front Oral Health. 2022;2.
Rezaei M, Ziai SA, Fakhri S, et al. ACE2: Its potential role and regulation in severe acute respiratory syndrome and COVID-19. J Cell Physiol. 2021;236:2430–2442.
Gomes-Filho IS, Cruz S, Trindade SC, et al. Periodontitis and respiratory diseases: A systematic review with meta-analysis. J Oral diseases. 2020;26(2):439–446.
Sukumar K, Tadepalli A. Nexus between COVID-19 and periodontal disease. J Int Med Res. 2021;49(3).
Takahashi Y, Watanabe N, Kamio N, et al. Expression of the SARS-CoV-2 Receptor ACE2 and Proinflammatory Cytokines Induced by the Periodontopathic Bacterium Fusobacterium nucleatum in Human Respiratory Epithelial Cells. Int J Mol Sci. 2021;22(3):1352.
Bui FQ, Almeida-da-Silva C, Huynh B, et al. Association between periodontal pathogens and systemic disease. Biomed J. 2019;42(1):27–35.
Katz J, Yue S, Xue W. Dental diseases are associated with increased odds ratio for coronavirus disease 19. Oral Dis. 2022;28(Suppl 1):991–993.
Anand PS, Jadhav P, Kamath KP, et al. A case-control study on the association between periodontitis and coronavirus disease (COVID-19). J Clin Periodontol. 2022;93(4):584–590.
Said KN, Al-Momani AM, Almaseeh JA, et al. Association of periodontal therapy, with inflammatory biomarkers and complications in COVID-19 patients: a case control study. Clin Oral Investig. 2022;26:6721–6732.
Wadhwa S, Dave S, Daily ML, et al. The Role of Oral Health in the Acquisition and Severity of SARS-CoV-2: A Retrospective Chart Review. Saudi Dent J. 2022;34(7):596–603.
Gupta S, Mohindra R, Singla M, et al. The clinical association between Periodontitis and COVID-19. Clin Oral Investig. 2022;26(2):1361–1374.
Kaur A, Sandhu HS, Sarwal A, et al. Assessment of correlation of COVID-19 infection and periodontitis – A comparative study. J Family Med Prim Care. 2022;11(5):1913–1917.
Baima G, Marruganti C, Sanz M, et al. Periodontitis and COVID-19: Biological Mechanisms and Meta-analyses of Epidemiological Evidence. J Dent Res. 2022;101(12):1430–1440.
Larvin H, Wilmott S, Wu J, et al. The Impact of Periodontal Disease on Hospital Admission and Mortality During COVID-19 Pandemic. Front Med. 2020;7.
Bao L, Zhang C, Dong J, et al. Oral Microbiome and SARS-CoV-2: Beware of Lung Co-infection. Front Microbiol. 2020;11:1840.
Aquino-Martinez R, Hernández-Vigueras S. Severe COVID-19 Lung Infection in Older People and Periodontitis. J Clin Med. 2021;10(2):279.
Huang N, Pérez P, Kato T, et al. SARS-CoV-2 infection of the oral cavity and saliva. Nat Med. 2021;27(5):892–903.
Zheng M, Gao Y, Wang G, et al. Functional exhaustion of antiviral lymphocytes in COVID-19 patients. Cell Mol Immunol. 2020;17(5):533–535.
Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet. 2020;395(10229):1054–1062.
Grigoriadis A, Räisänen IT, Pärnänen P, et al. Is There a Link between COVID-19 and Periodontal Disease? A Narrative Review. Eur J Dent. 2022;16(03):514–520.
Campisi G, Bizzoca ME, Lo Muzio L. COVID-19 and periodontitis: reflecting on a possible association. Head Face Med. 2021;17(16).
Kara C, Çelen K, Dede FO, et al. Is periodontal disease a risk factor for developing severe Covid-19 infection? The potential role of Galectin-3. Exp Biol Med. 2020;245(16):1425–1427.
Khandia R, Singhal S, Alqahtani T, et al. Emergence of SARS-CoV-2 Omicron (B.1.1.529) variant, salient features, high global health concerns and strategies to counter it amid ongoing COVID-19 pandemic. Environ Res. 2022;209.
Dong R, Zhang M, Hu Q, et al. Galectin-3 as a novel biomarker for disease diagnosis and a target for therapy (Review). Int J Mol Med. 2018;41(2):599–614.
Azarpazhooh A, Leake JL. Systematic review of the association between respiratory diseases and oral health. J Periodontol. 2006;77:1465–1482.