A Commentary on

Molina A, Huck O, Herrera D, Montero E.

The association between respiratory diseases and periodontitis: A systematic review and meta-analysis. J Clin Periodontol 2023; https://doi.org/10.1111/jcpe.13767.

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Over the last few decades increasing research has been directed at establishing whether the relationship between periodontitis and systemic diseases (such as diabetes mellitus) is unidirectional or bidirectional i.e. periodontitis can independently negatively affect systemic health1. Contemporary attitudes have shifted, and it is now understood that diabetes mellitus is not only a significant risk factor for developing periodontitis and worse treatment outcomes, but that poorly controlled periodontitis may impair systemic glycaemic control and that periodontal therapy may help to improve glycaemic control, comparable to a second line pharmacological agent2. There is biological evidence to support the theory that periodontitis may adversely affect respiratory health however there is little evidence to support the strength of such an association or the effects of periodontal therapy on respiratory diseases3.

From a biological perspective, two main theories have been suggested to explain the hypothesised association: the micro-aspiration of oral microbes into the respiratory apparatus and the systemic effects of pro-inflammatory mediators produced in the periodontium may affect the respiratory system increasing the likelihood of developing inflammatory respiratory conditions or worsening progression of existing diseases4.

This study aimed to investigate the epidemiological evidence for the association between periodontitis and respiratory diseases prevalence in addition to the clinical trial evidence of the effects of periodontal therapy on respiratory disease outcomes.

This study was commissioned by the European Federation of Periodontology to be used in a joint workshop with the World Organisation of Family Doctors. This aimed to improve ties between physicians and dentists in an attempt to reduce the global burden of noncommunicable diseases. The outcomes of this workshop have also been published in the same journal5.

Whilst the findings of this study suggest periodontitis may increase the incidence of certain respiratory diseases, caution must be taken when interpreting such epidemiological evidence to avoid describing this as a relationship – rather an association. Limited research was found investigating the effects of periodontal therapy on respiratory disease outcomes.

This systematic review was commendably well-designed and executed however was affected by similar shortcomings to most research in this area notably the lack of interventional studies and heterogeneity of case definition. Nonetheless, its findings should be recognised, and healthcare professionals should be aware of the possibility of periodontitis negatively affecting respiratory health and act accordingly by encouraging individuals with either periodontitis or respiratory diseases to optimise their oral health. This is perhaps more important for individuals in an in-patient setting whose systemic comorbidities are severe and whose oral health is often a low priority.

Whilst the findings of this study are unlikely to transform our understanding, it provides dental care professionals a basis to liaise with their colleagues when managing periodontitis patients with systemic comorbidities and may allow them to better inform their patients about its risks and thus motivate them.