Gutmann JL. Dental Historian 2017;62: 81–90

In the early decades of the 20th century, the medical profession felt that oral sepsis (focal infection) was responsible for 'various diseases .... which have been found to result from the action of micro-organisms which have collected in the mouth'. It was suggested that oral sepsis was not only a consequence of oral conditions, such as 'pyorrhea alveolaris', but also a result of dental procedures themselves ('foul septic toothplate stomatitis'). Whilst admiring the technical skills of dental surgeons, one physician felt that no one, rich or poor, was free from the surgical malpractice of building 'mausoleums of gold over a mass of sepsis'. However, others felt that poverty and a consequent inability to afford dental treatment was largely responsible for these infections. The sole treatment suggested by physicians for these conditions was a full dental clearance.

Dentists, however, began to think that there was a lack of evidence for both the assumption of the connection between oral infection and systemic disease and the relevance of the drastic treatment prescribed. They cited insufficient payments to carry out treatment, stating that they 'cannot get paid for the time needed to remove pulps properly and to seal root canals aseptically', and a lack of co-operation and understanding between the medical and dental professions, as possible causes of the problem. By 1938, focal infection was being described as an example of 'a medical theory ..... which is in danger of being converted ..... into the status of accepted fact'. At the same time in the USA, study clubs and learned societies with an interest in endodontics began to meet, indicating the real interest of the dental profession in the preservation and restoration of teeth, rather than their wholesale extraction.

Between 1947 and 1989, 82 papers were published, addressing possible links between oral and systemic disease. Since 1989, however, there have been more than 1,200 such publications. These indicate that there are associations between oral disease and conditions such as coronary heart disease, stroke, pneumonia, diabetes, liver disease, rheumatoid arthritis and infant low birth weight. Whilst these links are not established as causal, the relationship between the mouth and the rest of the human body is being made yet again but this time on a scientific basis, showing that the dental profession does have a role to play in the health of the patient as a whole. Whether science can similarly establish links between oral disease and poverty, payment systems and a lack of inter-professional co-operation was beyond the scope of this paper.