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  • Writer's pictureSonia Joshi

‘Covid patients with gum disease NINE TIMES more likely to die, study warns’ – The Sun

By Sonia Joshi

Unfortunately, the BDA estimates that over 20million people in the U.K. have missed dental appointments due to the Pandemic. The results of the recent study highlight the importance of encouraging patients to maintain their oral health during the pandemic, emphasising the importance of good periodontal health to help assist in the battle against adverse COVID 19 outcomes.

This two-part article aims to summarise the results of the recent study and look at ways we can raise awareness of the importance of periodontal health to provide more holistic care for our patients, whilst encouraging them to continue to maintain their oral health.

Part one (below) takes a closer at the study behind the headlines.


Association of Periodontitis and Severity of COVID -19 Infection: A case-controlled study’ 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. doi:10.1111/jcpe.13435.

A summary is provided below, if you would like to review the full article, please click on the link above.


  • Periodontitis is one of the most prevalent non communicable disease, with mild to moderate disease affecting 40-50% of the adult population and 10% of the population being affected with severe disease.

  • Periodontitis is characterised by a dysbiosis in the subgingival biofilm resulting in a chronic non resolving inflammatory response of the periodontal tissues. This chronic inflammation has been shown to increase low levels of systemic inflammation including elevation in circulating cytokines and acute phase proteins such as CRP.

  • Periodontal health is associated with poorer systemic health (independently of other shared co morbidities). A number of studies have already shown that periodontitis negatively impacts diabetes and cardiovascular disease relating to bacteraemia; increased levels of systemic inflammation and auto immune damage.

  • Periodontal treatment can improve systemic health status e.g. improved glycaemic control and renal function in patients with T2DM, improved lipid and glucose metabolism and reduction in systemic markers of inflammation.

  • Severe cases of COVID-19 are usually complicated by acute respiratory distress syndrome (ARDS), sepsis and shock with a number of patients with severe disease experiencing a pronounced pro inflammatory cytokine response referred to as the ‘cytokine storm’.

  • The commonalties between COVID-19 and periodontitis means there is a biological plausibility for an association between these two diseases.


The aim of this case-controlled study was to assess the extent to which periodontitis was associated with COVID-19 complications.


  • The case-controlled study enrolled 538 patients with a diagnosis of COVID-19 in Qatar between February- July 2020 using a national electronic data base which contains medical and dental information.

  • Adults aged 18+, diagnosed with COVID-19 (based on PCR testing) and with active dental records (at least one dental appointment the year preceding the pandemic) and existing radiographs were recruited.

  • A diagnosis of periodontitis was based on radiographic evidence of bone loss relative to root length (excluding bone loss related to local factors e.g. impacted third molars/ perio endo lesions etc). Based on the study design, patients were categorized as (a) healthy or initial periodontitis (bone loss less than the coronal 1/3) vs (b) stage 2-4 periodontitis (bone loss > coronal 1/3).

  • Other co variates that may affect COVID 19 and periodontitis including BMI, smoking and pre-existing medical conditions, blood tests of circulating inflammatory markers were also collected.

  • Associations between periodontitis and COVID-19 complications were analysed using logistic regression analysis adjusted for co variates including demographics, medical and behavioural factors.


Results revealed a positive link between worse COVID- 19 outcomes in patients with periodontitis. In particular periodontitis was associated with:

  • Higher risk of admission to intensive care units (ICU) 3.54 (95% CI 1.39–9.05)

  • Need for assisted ventilation 4.57 (95% CI 1.19–17.4)

  • Death in Covid‐19 patients 8.81 (95% CI 1.00-77.7)

  • Increased risk of all COVID-19 complications 3.67 (95% CI 1.46–9.27)

  • Increased blood levels of biomarkers linked to worse disease outcomes

Study Limitations

  • The current study did not address causality

  • Although the new diagnostic criteria for staging periodontitis was used, there was no clinical examination and diagnosis was based on radiographic analysis only

  • No distinction was made between a reduced but stable periodontium vs. ‘active’ periodontal disease

  • There was a large CI range for mortality (1.00-77.7) and larger studies will be required to help provide a narrower, more accurate CI range.

  • Study was population specific and larger multicentre studies across differing populations would help to see the global application of these results

  • We do not yet know the interplay between emerging mutations and periodontitis


  • The discussion focuses on a number of theories addressing the biological plausibility to explain the strong correlation between adverse COVID- 19 outcomes and presence of periodontal disease e.g. effects of inhalation of periodontopathic bacteria on the lower respiratory tract

  • Limitations are also highlighted

Conclusion and impact

  • This study highlighted a relationship between periodontitis and worse COVID-19 outcomes even after accounting for effects of confounding variables

  • In other studies, successful periodontal treatment has been shown to reduce systemic marker of inflammation and hence periodontal treatment may play a role in reducing the overall inflammatory burden in COVID 19 patients, potentially reducing the risk of severe complications

  • Oral health may play a key part in the hospital management of patients with COVID-19

  • Highlights the importance of oral health and good oral hygiene as a public health measure

  • Further studies looking at causal relationship and effects of periodontal intervention relating to COVID- 19 would be beneficial

  • Further studies looking at associations between periodontitis and emerging strains of SARS-CoV- 2 to assess impact and relationship would provide real time data on interplay of mutations and periodontal disease

1 Comment

Mar 13, 2021

Excellent summary of an interesting study highlighting the links between periodontal health and systemic disease, this time the Covid-19 virus. Now we have yet another reason to tell our patients why it so important to maintain good periodontal health.

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