Oral health manifestations in long COVID: a Brazilian cross-sectional study
- Journal of Dental Health, Oral Disorders & Therapy
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Sonia Groisman,1 João Guilherme Medeiros,2 Marijoe Braga Alves Simões,1 Eduardo Buzanovsky-Louzada,3 Marcela Moutinho,3 Maria Eduarda de Souza Melo-Oliveira,4 Débora Dummer Meira,5 Bartolomeu Acioli-Santos,6 Danilo Elias Xavier,6 Iúri Drumond Louro,5 Elizeu Fagundes de Carvalho,5 Luís Cristóvão Porto,3 Esther Okorodudu,8 Raman Bedi7,8
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Abstract
Background: Long COVID affects multiple systems, yet oral manifestations remain incompletely characterised. The oral cavity’s high ACE2 receptor expression suggests potential for persistent SARS-CoV-2 effects. Aims: To investigate associations between oral health conditions and long COVID in individuals with previous SARS-CoV-2 infection. Methods: Cross-sectional study of 402 participants at a Brazilian university hospital (March 2020–October 2024). Standardised oral examinations assessed periodontal disease, oral lesions, xerostomia, and bleeding. Long COVID was defined as symptoms persisting >90 days post-infection (WHO criteria). Chi-square tests and odds ratios were used to evaluate associations. Due to the exploratory nature of this study and the absence of multivariable adjustment, findings should be interpreted as hypothesis-generating. Results: Among 293 participants with previous SARS-CoV-2 infection, 116 (39.6%) met long COVID criteria. Oral lesions (5.8% vs 3.7%, P=0.02) and xerostomia (3.8% vs 0%, P=0.01) were more prevalent in those with a history of infection. Xerostomia was numerically higher in long COVID patients (14.7% vs 9.3%) but did not reach statistical significance (P=0.083). Unexpectedly, periodontal disease was less common in long COVID patients (6.0% vs 15.6%, P=0.01). Xerostomia in long COVID was associated with memory loss, fatigue, and dry eyes. Women comprised 80.2% of long COVID cases. Conclusion: Oral manifestations, particularly xerostomia and oral lesions, are associated with though not necessarily caused by long COVID. The paradoxical lower prevalence of periodontal disease warrants further investigation and may reflect selection bias or unmeasured confounders. The study is limited by its cross-sectional design, absence of multivariable adjustment, and reliance on self-reported infection history; causal inference is not possible. Dentists should remain aware of persistent oral symptoms in patients with a history of COVID-19.
Keywords
long covid, oral manifestations, xerostomia, periodontal disease, oral lesions, cross-sectional study, oral health
