Study subjects were obtained from the pool of OPD patients in the Department of Conservative Dentistry and Endodontics, PGIDS, Rohtak, and the Department of Cardiology, PGIMS, Rohtak. Baseline clinical, radiographic, and laboratory parameters (hsCRP and IL-6) were recorded. Patients were then randomly allocated to one of the two groups. In the test group, single-sitting root canal treatment was performed immediately, while in the control group, delayed endodontic intervention (after 3 months) was performed after three months. Clinical and laboratory parameters were again assessed at the end of 3 months in both groups. hsCRP and IL-6 indices were again done in the delayed treatment group after 3 months of root canal treatment.

Inclusion Criteria:

1. Individuals 30 years of age and older, with a diagnosis of stable coronary artery disease (CAD) and chronic apical periodontitis.

2. All patients had to present with CAD defined by the Brazilian Society of Cardiology (Xavier et al., 2013) as the documented occurrence of one or more of the following events 6 months before entering the study: history of myocardial infarction, stable angina or ischaemia in non-invasive tests; surgical or percutaneous myocardial revascularization and lesion size of greater than 50% in at least one major coronary artery, as assessed by angiography; presence of angina and positive results of non-invasive testing of ischaemia.

3. Presence of apical periodontitis defined by the presence of at least 1 radiographic radiolucency ( ≥ 3mm) in teeth as assessed both clinically and radiographically ,with periapical index (PAI) scores ≥3 in a single permanent tooth and pulp necrosis verified by cold and electric pulp test.

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Exclusion Criteria:

1. Chronic conditions associated with periodontitis or with changes in systemic inflammation (e.g. diabetes mellitus, rheumatoid arthritis, rheumatic fever, malignancy, respiratory diseases, renal diseases).
2. Presence of localized or diffuse periodontal disease.
3. Acute symptomatic patients
4. Presence of CV risk factor - history of smoking
5. Acute conditions known to affect systemic inflammatory markers (orthopaedic trauma, surgery ,viral infections)
6. Medications (during last 3 months) known to affect systemic inflammatory markers (systemic steroids,immunosuppressants, hormone replacement therapy, contraceptives and systemic antibiotics
7. Obesity (body mass index [BMI]≥30 kg/m2
8. Pregnancy & Lactation.37