The Invasive Dentistry – Endocarditis Association Study



Infective endocarditis (IE), an infection of the lining of the heart – particularly the heart valves, is a serious disease with high morbidity and mortality. Bacteria from the mouth are implicated as the cause in some cases. It is not clear if, and to what extent, these bacteria enter the circulation during daily activities such as chewing food and cleaning teeth or as a result of invasive dental procedures such as extractions, root canal treatment and dental scaling.

Because of the presumed link to invasive dental procedures, taking antibiotics before invasive dental procedures as a precautionary measure, known as antibiotic prophylaxis (AP), has been the main focus of IE prevention for over 60 years and remains the standard of care for individuals at high-risk of IE in most parts of the world. However, there has never been a randomised clinical trial (RCT) of AP.

Because of this lack of evidence, the National Institute for Health and Care Excellence (NICE) produced a guideline recommending cessation of AP in 2008. The UK is now the only country in the world where AP is not recommended for patients at high-risk of IE. Recent research, however, has shown a significant increase in the incidence of IE following introduction of the NICE guidelines in March 2008, although the reasons for this are unclear. This increase has raised concerns about the advice not to give AP prior to invasive dental procedures in the UK.

Aims & methods

The IDEA-Study will link national data on courses of dental treatment or invasive medical/surgical procedures and hospital admissions for IE to investigate if there is a link between invasive dental procedures or invasive medical/surgical procedures and the development of IE. We will address the following questions:

  • Is the frequency of invasive procedures higher in the 3 months immediately before an IE diagnosis than in other 3 month periods?
  • Is the incidence of IE higher in the 3 months immediately following an invasive procedure than in the 3 months following treatments that do NOT involve an invasive procedure?
  • If there is an association between invasive procedures and IE, do some types of invasive procedure have a greater likelihood of causing IE than others (e.g. comparing tooth extractions with dental scaling and root canal treatment)?
  • Is the risk of IE following an invasive procedure greater in those considered at ‘high-risk’ of developing IE?

Why this research is needed now

There is a lack of good quality data on this issue. Most of the literature consists of case reports, animal studies and poorly designed or underpowered observational studies.

Aims & objectives

The IDEA-Study will link national data on courses of dental treatment or invasive medical/surgical procedures and hospital admissions for infective endocarditis (IE) to investigate if there is a link between these invasive procedures and the development of IE.


This research has been funded by a grant from the National Institute for Health Research (NIHR) through their Health Technology Assessment (HTA) programme. Further details of the study can be obtained at the studies NIHR-HTA web site.

Protecting Patients

This study involves linking data held on two large National Health Service (NHS) databases – The NHS Digital Database that holds data on all hospital admissions in England and the NHS Business Services Authority (NHSBSA) Dental Database that holds data on all NHS courses of dental treatment in England. This is necessary to allow us to identify any patients admitted to hospital in England with IE, or other medical conditions that might be associated with invasive dental procedures, and confirm the timing of any invasive dental treatment they might have received in the preceding year.

Patient identifying information already held by the NHS will be used by NHS BSA to link these two sets of data. However, this will be done entirely by the NHS. No patient identifying information (such as name, date of birth or address) will be made available to the researchers. All identifiable data will be removed by the NHS data managers before any data is made available to the research team; all data received by the research team will be ‘pseudonymised’ (i.e. NHS Digital will assign a non-identifying ID number to each record, in place of the deleted identifiable information such as names, dates of birth etc.). We have also obtained the approval of both the NHS Research Ethics Service and the NHS Health Research Authority Confidentiality Advisory Group (CAG) before the release of any data. No record-level data used in this study will be transferred to any third country or international organisation at any point. The overall Data Retention Period for the project ends on 02/12/2021, and all original personal data will be securely deleted by this date.

Despite these safeguards, should any individual wish to have data related to them excluded from the study i.e. wish to exercise their Patient’s Right of Objection to their data being used for research, or their Right to Erasure (‘right to be forgotten’) under article 17 of GDPR, they should contact the IDEA Study Team at requesting that their data be excluded from the study and providing their full name, sex, date of birth and address details so that NHS Digital / NHSBSA can identify their data and exclude it from any data extraction or linkage performed in connection with this study. This study involves no decision making or profiling that would produce a legal or other significant effect on any participant.

Data Controller

The University of Sheffield is the Data Controller for this study. Please see the University of Sheffield General Privacy Notice for information on the handling of personal data by the university for research (e.g. this study), including details of the data protection officer, supervisory authority, right of complaint, and lawful basis for data processing under GDPR.

Contact us

For more information, please contact Professor Martin Thornhill on